Question:
The controller-manager node-lifecycle-controller watches node lease and update probeTimestamp , and it check node probeTimestamp is before . The node-monitor-grace-period default value is 40s. When the client connection lost, the lease watcher cannot receive new event. With the http2 health check, HTTP2PINGTIMEOUTSECONDS default is 30s, HTTP2READIDLETIMEOUTSECONDS default is 15s, it will delay 45s to kill http2 connection. During this period, node-lifecycle-controller will mark all nodes NotReady. Here are some logs When the http2 connection lost, the watch should stop as soon as possible. The reflector should relist resource, and node-lifecycle-controller should not mark all node NotReady. HTTP2PINGTIMEOUTSECONDS+HTTP2READIDLETIMEOUTSECONDS should be less than 40s. the controller-manager node-lifecycle-controller watch client srcIP:srcPort. Drop all tcp package send into srcIP:srcPort. for more than 40 seconds, all node will be marked NotReady node will be Ready after some seconds. No response <details</details<details</details<details</details<details</details<details</details<details</details
How about double-check node lease before marking node NotReady? The node-lifecycle-controller can get reference lease from apiserver with
/sig node
/sig api-machinery
/cc We have discussed this timeouts values before and myself, I also think got some metrics with lower timeouts for the HTTP2 connections. In this situation is clear that the defaults of the node watcher and the timeouts are related and having good defaults will be ideal, but the question is which values do we change ?
I think in internal network, the ping response almost return in 1 second, the HTTP2PINGTIMEOUT_SECONDS default value should be 5 seconds. And the total timeout will 35 seconds. WDYT?
/triage accepted any pointers in other places where those timeouts were changed for http2? Any notes from those discussions?
/priority important-longterm since it is not a regression I will keep it longterm priority and not higher. But we can reevaluate if we hear more reports about it.
/assign
I'm investigating problems similar to this, but I'm looking for a way to confirm this is what is happening - and if there are tips for how to recreate such a scenario, that would be very helpful. We get infrequent reports of "worker goes NotReady for a short time" incidents that appear to be triggered by events like failing over a LB sitting front of the kube-apiservers. We've done some tests with a simple client-go app and have recreated a scenario in which the app logs messages after 45 secs of "context exceeded" errors. The failures reported to us from customers don't have http2 errors in the kubelet logs, and our attempts to recreate with kubelet have never shown more more than a single error which works on subsequent retry.
Hi folks, we have a simulated recreate of the problem. This recreate involves injecting a 40 second delay in "connectivity" between the Kubernetes API server and etcd (we a 40 second delay to etcd defrag and defragged all etcd members at the same time). The connectivity between these two components is obviously critical to nodes successfully updating their leases in order to stay ready. We use 40 seconds because it matches . The test will usually cause one or more of the cluster nodes will flap their readiness state. Setting on the Kubernetes controller manager prevents the flap. Given this, I think that one or more of the Kubernetes default configurations needs to change in order to tolerate such "connectivity" problems in order to maintain healthy node state.
What's the proposal then? Do we update --node-monitor-grace-period to 50s? It seems the less risky change as the client-go defaults are more sensitive and impact the whole ecosystem, beyond kubernetes itself are you open to increase this default? It seems worth it to improve the reliability of cluster
I think we should update .
can someone send a PR to see how it will look like?
I have been following this discussion as we had encountered the bug as well. I have created a PR - Please let me know if it works
I'll add another data point from our testing. Namely, the simulated recreate noted depends on the Kubernetes controller manager (KCM) leader election configuration. Using the following leader election configuration for the KCM yields a KCM that has no leader after the delayed etcd defrag. As a result, nodes won't be marked not ready unless the KCM leadership is restored before the nodes renew their lease. Extending the KCM leader election configuration to the following, makes the problem easier to recreate.
/assign Reassigning the issue to me

if obj.PodEvictionTimeout == zero { obj.PodEvictionTimeout = metav1.Duration{Duration: 5 * time.Minute} } <ins> // NodeMonitorGracePeriod is set to a default value of 50 seconds. // This value should be greater than the sum of HTTP2_PING_TIMEOUT_SECONDS (30s) // and HTTP2_READ_IDLE_TIMEOUT_SECONDS (15s) from the http2 health check // to ensure that the server has adequate time to handle slow or idle connections // properly before marking a node as unhealthy. </ins> if obj.NodeMonitorGracePeriod == zero { <del> obj.NodeMonitorGracePeriod = metav1.Duration{Duration: 40 * time.Second} </del> <ins> obj.NodeMonitorGracePeriod = metav1.Duration{Duration: 50 * time.Second} </ins> } if obj.NodeStartupGracePeriod == zero { obj.NodeStartupGracePeriod = metav1.Duration{Duration: 60 * time.Second}


Question:
The controller-manager node-lifecycle-controller watches node lease and update probeTimestamp , and it check node probeTimestamp is before . The node-monitor-grace-period default value is 40s. When the client connection lost, the lease watcher cannot receive new event. With the http2 health check, HTTP2PINGTIMEOUTSECONDS default is 30s, HTTP2READIDLETIMEOUTSECONDS default is 15s, it will delay 45s to kill http2 connection. During this period, node-lifecycle-controller will mark all nodes NotReady. Here are some logs When the http2 connection lost, the watch should stop as soon as possible. The reflector should relist resource, and node-lifecycle-controller should not mark all node NotReady. HTTP2PINGTIMEOUTSECONDS+HTTP2READIDLETIMEOUTSECONDS should be less than 40s. the controller-manager node-lifecycle-controller watch client srcIP:srcPort. Drop all tcp package send into srcIP:srcPort. for more than 40 seconds, all node will be marked NotReady node will be Ready after some seconds. No response <details</details<details</details<details</details<details</details<details</details<details</details
How about double-check node lease before marking node NotReady? The node-lifecycle-controller can get reference lease from apiserver with
/sig node
/sig api-machinery
/cc We have discussed this timeouts values before and myself, I also think got some metrics with lower timeouts for the HTTP2 connections. In this situation is clear that the defaults of the node watcher and the timeouts are related and having good defaults will be ideal, but the question is which values do we change ?
I think in internal network, the ping response almost return in 1 second, the HTTP2PINGTIMEOUT_SECONDS default value should be 5 seconds. And the total timeout will 35 seconds. WDYT?
/triage accepted any pointers in other places where those timeouts were changed for http2? Any notes from those discussions?
/priority important-longterm since it is not a regression I will keep it longterm priority and not higher. But we can reevaluate if we hear more reports about it.
/assign
I'm investigating problems similar to this, but I'm looking for a way to confirm this is what is happening - and if there are tips for how to recreate such a scenario, that would be very helpful. We get infrequent reports of "worker goes NotReady for a short time" incidents that appear to be triggered by events like failing over a LB sitting front of the kube-apiservers. We've done some tests with a simple client-go app and have recreated a scenario in which the app logs messages after 45 secs of "context exceeded" errors. The failures reported to us from customers don't have http2 errors in the kubelet logs, and our attempts to recreate with kubelet have never shown more more than a single error which works on subsequent retry.
Hi folks, we have a simulated recreate of the problem. This recreate involves injecting a 40 second delay in "connectivity" between the Kubernetes API server and etcd (we a 40 second delay to etcd defrag and defragged all etcd members at the same time). The connectivity between these two components is obviously critical to nodes successfully updating their leases in order to stay ready. We use 40 seconds because it matches . The test will usually cause one or more of the cluster nodes will flap their readiness state. Setting on the Kubernetes controller manager prevents the flap. Given this, I think that one or more of the Kubernetes default configurations needs to change in order to tolerate such "connectivity" problems in order to maintain healthy node state.
What's the proposal then? Do we update --node-monitor-grace-period to 50s? It seems the less risky change as the client-go defaults are more sensitive and impact the whole ecosystem, beyond kubernetes itself are you open to increase this default? It seems worth it to improve the reliability of cluster
I think we should update .
can someone send a PR to see how it will look like?
I have been following this discussion as we had encountered the bug as well. I have created a PR - Please let me know if it works
I'll add another data point from our testing. Namely, the simulated recreate noted depends on the Kubernetes controller manager (KCM) leader election configuration. Using the following leader election configuration for the KCM yields a KCM that has no leader after the delayed etcd defrag. As a result, nodes won't be marked not ready unless the KCM leadership is restored before the nodes renew their lease. Extending the KCM leader election configuration to the following, makes the problem easier to recreate.
/assign Reassigning the issue to me

//    be less than the node health signal update frequency, since there will //    only be fresh values from Kubelet at an interval of node health signal //    update frequency. <del> // 2. nodeMonitorGracePeriod can't be too large for user experience - larger </del> <ins> // 2. nodeMonitorGracePeriod should be greater than the sum of HTTP2_PING_TIMEOUT_SECONDS (30s) // 	  and HTTP2_READ_IDLE_TIMEOUT_SECONDS (15s) from the http2 health check // 	  to ensure that the server has adequate time to handle slow or idle connections //    properly before marking a node as unhealthy. // 3. nodeMonitorGracePeriod can't be too large for user experience - larger </ins> //    value takes longer for user to see up-to-date node health. nodeMonitorGracePeriod time.Duration


Question:
The controller-manager node-lifecycle-controller watches node lease and update probeTimestamp , and it check node probeTimestamp is before . The node-monitor-grace-period default value is 40s. When the client connection lost, the lease watcher cannot receive new event. With the http2 health check, HTTP2PINGTIMEOUTSECONDS default is 30s, HTTP2READIDLETIMEOUTSECONDS default is 15s, it will delay 45s to kill http2 connection. During this period, node-lifecycle-controller will mark all nodes NotReady. Here are some logs When the http2 connection lost, the watch should stop as soon as possible. The reflector should relist resource, and node-lifecycle-controller should not mark all node NotReady. HTTP2PINGTIMEOUTSECONDS+HTTP2READIDLETIMEOUTSECONDS should be less than 40s. the controller-manager node-lifecycle-controller watch client srcIP:srcPort. Drop all tcp package send into srcIP:srcPort. for more than 40 seconds, all node will be marked NotReady node will be Ready after some seconds. No response <details</details<details</details<details</details<details</details<details</details<details</details
How about double-check node lease before marking node NotReady? The node-lifecycle-controller can get reference lease from apiserver with
/sig node
/sig api-machinery
/cc We have discussed this timeouts values before and myself, I also think got some metrics with lower timeouts for the HTTP2 connections. In this situation is clear that the defaults of the node watcher and the timeouts are related and having good defaults will be ideal, but the question is which values do we change ?
I think in internal network, the ping response almost return in 1 second, the HTTP2PINGTIMEOUT_SECONDS default value should be 5 seconds. And the total timeout will 35 seconds. WDYT?
/triage accepted any pointers in other places where those timeouts were changed for http2? Any notes from those discussions?
/priority important-longterm since it is not a regression I will keep it longterm priority and not higher. But we can reevaluate if we hear more reports about it.
/assign
I'm investigating problems similar to this, but I'm looking for a way to confirm this is what is happening - and if there are tips for how to recreate such a scenario, that would be very helpful. We get infrequent reports of "worker goes NotReady for a short time" incidents that appear to be triggered by events like failing over a LB sitting front of the kube-apiservers. We've done some tests with a simple client-go app and have recreated a scenario in which the app logs messages after 45 secs of "context exceeded" errors. The failures reported to us from customers don't have http2 errors in the kubelet logs, and our attempts to recreate with kubelet have never shown more more than a single error which works on subsequent retry.
Hi folks, we have a simulated recreate of the problem. This recreate involves injecting a 40 second delay in "connectivity" between the Kubernetes API server and etcd (we a 40 second delay to etcd defrag and defragged all etcd members at the same time). The connectivity between these two components is obviously critical to nodes successfully updating their leases in order to stay ready. We use 40 seconds because it matches . The test will usually cause one or more of the cluster nodes will flap their readiness state. Setting on the Kubernetes controller manager prevents the flap. Given this, I think that one or more of the Kubernetes default configurations needs to change in order to tolerate such "connectivity" problems in order to maintain healthy node state.
What's the proposal then? Do we update --node-monitor-grace-period to 50s? It seems the less risky change as the client-go defaults are more sensitive and impact the whole ecosystem, beyond kubernetes itself are you open to increase this default? It seems worth it to improve the reliability of cluster
I think we should update .
can someone send a PR to see how it will look like?
I have been following this discussion as we had encountered the bug as well. I have created a PR - Please let me know if it works
I'll add another data point from our testing. Namely, the simulated recreate noted depends on the Kubernetes controller manager (KCM) leader election configuration. Using the following leader election configuration for the KCM yields a KCM that has no leader after the delayed etcd defrag. As a result, nodes won't be marked not ready unless the KCM leadership is restored before the nodes renew their lease. Extending the KCM leader election configuration to the following, makes the problem easier to recreate.
/assign Reassigning the issue to me

) const ( <del> testNodeMonitorGracePeriod = 40 * time.Second </del> <ins> testNodeMonitorGracePeriod = 50 * time.Second </ins> testNodeStartupGracePeriod = 60 * time.Second testNodeMonitorPeriod      = 5 * time.Second testRateLimiterQPS         = float32(100000)


Question:
The controller-manager node-lifecycle-controller watches node lease and update probeTimestamp , and it check node probeTimestamp is before . The node-monitor-grace-period default value is 40s. When the client connection lost, the lease watcher cannot receive new event. With the http2 health check, HTTP2PINGTIMEOUTSECONDS default is 30s, HTTP2READIDLETIMEOUTSECONDS default is 15s, it will delay 45s to kill http2 connection. During this period, node-lifecycle-controller will mark all nodes NotReady. Here are some logs When the http2 connection lost, the watch should stop as soon as possible. The reflector should relist resource, and node-lifecycle-controller should not mark all node NotReady. HTTP2PINGTIMEOUTSECONDS+HTTP2READIDLETIMEOUTSECONDS should be less than 40s. the controller-manager node-lifecycle-controller watch client srcIP:srcPort. Drop all tcp package send into srcIP:srcPort. for more than 40 seconds, all node will be marked NotReady node will be Ready after some seconds. No response <details</details<details</details<details</details<details</details<details</details<details</details
How about double-check node lease before marking node NotReady? The node-lifecycle-controller can get reference lease from apiserver with
/sig node
/sig api-machinery
/cc We have discussed this timeouts values before and myself, I also think got some metrics with lower timeouts for the HTTP2 connections. In this situation is clear that the defaults of the node watcher and the timeouts are related and having good defaults will be ideal, but the question is which values do we change ?
I think in internal network, the ping response almost return in 1 second, the HTTP2PINGTIMEOUT_SECONDS default value should be 5 seconds. And the total timeout will 35 seconds. WDYT?
/triage accepted any pointers in other places where those timeouts were changed for http2? Any notes from those discussions?
/priority important-longterm since it is not a regression I will keep it longterm priority and not higher. But we can reevaluate if we hear more reports about it.
/assign
I'm investigating problems similar to this, but I'm looking for a way to confirm this is what is happening - and if there are tips for how to recreate such a scenario, that would be very helpful. We get infrequent reports of "worker goes NotReady for a short time" incidents that appear to be triggered by events like failing over a LB sitting front of the kube-apiservers. We've done some tests with a simple client-go app and have recreated a scenario in which the app logs messages after 45 secs of "context exceeded" errors. The failures reported to us from customers don't have http2 errors in the kubelet logs, and our attempts to recreate with kubelet have never shown more more than a single error which works on subsequent retry.
Hi folks, we have a simulated recreate of the problem. This recreate involves injecting a 40 second delay in "connectivity" between the Kubernetes API server and etcd (we a 40 second delay to etcd defrag and defragged all etcd members at the same time). The connectivity between these two components is obviously critical to nodes successfully updating their leases in order to stay ready. We use 40 seconds because it matches . The test will usually cause one or more of the cluster nodes will flap their readiness state. Setting on the Kubernetes controller manager prevents the flap. Given this, I think that one or more of the Kubernetes default configurations needs to change in order to tolerate such "connectivity" problems in order to maintain healthy node state.
What's the proposal then? Do we update --node-monitor-grace-period to 50s? It seems the less risky change as the client-go defaults are more sensitive and impact the whole ecosystem, beyond kubernetes itself are you open to increase this default? It seems worth it to improve the reliability of cluster
I think we should update .
can someone send a PR to see how it will look like?
I have been following this discussion as we had encountered the bug as well. I have created a PR - Please let me know if it works
I'll add another data point from our testing. Namely, the simulated recreate noted depends on the Kubernetes controller manager (KCM) leader election configuration. Using the following leader election configuration for the KCM yields a KCM that has no leader after the delayed etcd defrag. As a result, nodes won't be marked not ready unless the KCM leadership is restored before the nodes renew their lease. Extending the KCM leader election configuration to the following, makes the problem easier to recreate.
/assign Reassigning the issue to me

}, "NodeMonitorGracePeriod": { SchemaProps: spec.SchemaProps{ <del> Description: "nodeMontiorGracePeriod is the amount of time which we allow a running node to be unresponsive before marking it unhealthy. Must be N times more than kubelet's nodeStatusUpdateFrequency, where N means number of retries allowed for kubelet to post node status.", </del> <ins> Description: "nodeMontiorGracePeriod is the amount of time which we allow a running node to be unresponsive before marking it unhealthy. Must be N times more than kubelet's nodeStatusUpdateFrequency, where N means number of retries allowed for kubelet to post node status. This value should also be greater than the sum of HTTP2_PING_TIMEOUT_SECONDS and HTTP2_READ_IDLE_TIMEOUT_SECONDS.", </ins> Ref:         ref("k8s.io/apimachinery/pkg/apis/meta/v1.Duration"), }, },


Question:
The controller-manager node-lifecycle-controller watches node lease and update probeTimestamp , and it check node probeTimestamp is before . The node-monitor-grace-period default value is 40s. When the client connection lost, the lease watcher cannot receive new event. With the http2 health check, HTTP2PINGTIMEOUTSECONDS default is 30s, HTTP2READIDLETIMEOUTSECONDS default is 15s, it will delay 45s to kill http2 connection. During this period, node-lifecycle-controller will mark all nodes NotReady. Here are some logs When the http2 connection lost, the watch should stop as soon as possible. The reflector should relist resource, and node-lifecycle-controller should not mark all node NotReady. HTTP2PINGTIMEOUTSECONDS+HTTP2READIDLETIMEOUTSECONDS should be less than 40s. the controller-manager node-lifecycle-controller watch client srcIP:srcPort. Drop all tcp package send into srcIP:srcPort. for more than 40 seconds, all node will be marked NotReady node will be Ready after some seconds. No response <details</details<details</details<details</details<details</details<details</details<details</details
How about double-check node lease before marking node NotReady? The node-lifecycle-controller can get reference lease from apiserver with
/sig node
/sig api-machinery
/cc We have discussed this timeouts values before and myself, I also think got some metrics with lower timeouts for the HTTP2 connections. In this situation is clear that the defaults of the node watcher and the timeouts are related and having good defaults will be ideal, but the question is which values do we change ?
I think in internal network, the ping response almost return in 1 second, the HTTP2PINGTIMEOUT_SECONDS default value should be 5 seconds. And the total timeout will 35 seconds. WDYT?
/triage accepted any pointers in other places where those timeouts were changed for http2? Any notes from those discussions?
/priority important-longterm since it is not a regression I will keep it longterm priority and not higher. But we can reevaluate if we hear more reports about it.
/assign
I'm investigating problems similar to this, but I'm looking for a way to confirm this is what is happening - and if there are tips for how to recreate such a scenario, that would be very helpful. We get infrequent reports of "worker goes NotReady for a short time" incidents that appear to be triggered by events like failing over a LB sitting front of the kube-apiservers. We've done some tests with a simple client-go app and have recreated a scenario in which the app logs messages after 45 secs of "context exceeded" errors. The failures reported to us from customers don't have http2 errors in the kubelet logs, and our attempts to recreate with kubelet have never shown more more than a single error which works on subsequent retry.
Hi folks, we have a simulated recreate of the problem. This recreate involves injecting a 40 second delay in "connectivity" between the Kubernetes API server and etcd (we a 40 second delay to etcd defrag and defragged all etcd members at the same time). The connectivity between these two components is obviously critical to nodes successfully updating their leases in order to stay ready. We use 40 seconds because it matches . The test will usually cause one or more of the cluster nodes will flap their readiness state. Setting on the Kubernetes controller manager prevents the flap. Given this, I think that one or more of the Kubernetes default configurations needs to change in order to tolerate such "connectivity" problems in order to maintain healthy node state.
What's the proposal then? Do we update --node-monitor-grace-period to 50s? It seems the less risky change as the client-go defaults are more sensitive and impact the whole ecosystem, beyond kubernetes itself are you open to increase this default? It seems worth it to improve the reliability of cluster
I think we should update .
can someone send a PR to see how it will look like?
I have been following this discussion as we had encountered the bug as well. I have created a PR - Please let me know if it works
I'll add another data point from our testing. Namely, the simulated recreate noted depends on the Kubernetes controller manager (KCM) leader election configuration. Using the following leader election configuration for the KCM yields a KCM that has no leader after the delayed etcd defrag. As a result, nodes won't be marked not ready unless the KCM leadership is restored before the nodes renew their lease. Extending the KCM leader election configuration to the following, makes the problem easier to recreate.
/assign Reassigning the issue to me

// nodeMontiorGracePeriod is the amount of time which we allow a running node to be // unresponsive before marking it unhealthy. Must be N times more than kubelet's // nodeStatusUpdateFrequency, where N means number of retries allowed for kubelet <del> // to post node status. </del> <ins> // to post node status. This value should also be greater than the sum of // HTTP2_PING_TIMEOUT_SECONDS and HTTP2_READ_IDLE_TIMEOUT_SECONDS. </ins> NodeMonitorGracePeriod metav1.Duration // podEvictionTimeout is the grace period for deleting pods on failed nodes. PodEvictionTimeout metav1.Duration


Question:
The issue is to follow up discussions in : running conformance test with the commonly used tool, sonobuoy, failed because the tool's test runner is lack of permission towards . The original issue was resolved by changing the e2e (conformance) test of to an integration test. Several problems remained: privilege requirement in is outdated. discovery is one of the least-privileged permissions, and is expected to be granted to every authenticated user but is not actually. the result returned by should be part of conformance? 1st and 2nd are straightforward to fix, not sure about 3rd, should we add a separate test or add a verification step in existing one like With the fix of 2nd, e2e for should no longer fail with any test runner. cc - should be reflect the accurate permission requirement discovery permission should be granted to all authenticated users. test should check the result returned by . Inapplicable No response <details</details<details</details<details</details<details</details<details</details<details</details
/sig api-machinery /sig testing
I agree with this. We have conformance tests around things like webhooks and custom resource definitions. I'd recommend rephrasing that as "limits itself to capabilities exposed via APIs (e.g., does not require root on nodes, access to raw network interfaces) and does not require write access to system namespaces (like kube-system)" I'm not sure I agree with this. No binaries Kubernetes provides (that I'm aware of) and nothing in client-go needs to make use of root discovery information. I'd be very slow to expand endpoints included in . Unless we have compelling reasons for people to use and rely on this data, I would lean towards no.
can we fix 1 , that seems that everybody agree and looks like the most clear one? the other sound more contentious
thanks for your comments. Created for 1 and closed the other one.
Thanks all. Agree on this outcome.
/triage accepted

"fmt" "math" "strconv" <del> "sync" </del> "time" "github.com/GoogleCloudPlatform/kubernetes/pkg/api"


Question:
The issue is to follow up discussions in : running conformance test with the commonly used tool, sonobuoy, failed because the tool's test runner is lack of permission towards . The original issue was resolved by changing the e2e (conformance) test of to an integration test. Several problems remained: privilege requirement in is outdated. discovery is one of the least-privileged permissions, and is expected to be granted to every authenticated user but is not actually. the result returned by should be part of conformance? 1st and 2nd are straightforward to fix, not sure about 3rd, should we add a separate test or add a verification step in existing one like With the fix of 2nd, e2e for should no longer fail with any test runner. cc - should be reflect the accurate permission requirement discovery permission should be granted to all authenticated users. test should check the result returned by . Inapplicable No response <details</details<details</details<details</details<details</details<details</details<details</details
/sig api-machinery /sig testing
I agree with this. We have conformance tests around things like webhooks and custom resource definitions. I'd recommend rephrasing that as "limits itself to capabilities exposed via APIs (e.g., does not require root on nodes, access to raw network interfaces) and does not require write access to system namespaces (like kube-system)" I'm not sure I agree with this. No binaries Kubernetes provides (that I'm aware of) and nothing in client-go needs to make use of root discovery information. I'd be very slow to expand endpoints included in . Unless we have compelling reasons for people to use and rely on this data, I would lean towards no.
can we fix 1 , that seems that everybody agree and looks like the most clear one? the other sound more contentious
thanks for your comments. Created for 1 and closed the other one.
Thanks all. Agree on this outcome.
/triage accepted

Expect(badEvents).NotTo(BeNumerically(">", int(math.Floor(0.01*float64(totalPods))))) }) } <del> type Scalability struct { skip          bool totalPods     int podsPerMinion int rcsPerThread  int } scalabilityTests := []Scalability{ {totalPods: 500, podsPerMinion: 10, rcsPerThread: 5, skip: true}, {totalPods: 500, podsPerMinion: 10, rcsPerThread: 25, skip: true}, } for _, testArg := range scalabilityTests { // # of threads calibrate to totalPods threads := (testArg.totalPods / (testArg.podsPerMinion * testArg.rcsPerThread)) name := fmt.Sprintf( "should be able to launch %v pods, %v per minion, in %v rcs/thread.", testArg.totalPods, testArg.podsPerMinion, testArg.rcsPerThread) if testArg.skip { name = "[Skipped] " + name } itArg := testArg It(name, func() { podsLaunched := 0 var wg sync.WaitGroup wg.Add(threads) // Create queue of pending requests on the api server. for i := 0; i < threads; i++ { go func() { defer wg.Done() for i := 0; i < itArg.rcsPerThread; i++ { name := "my-short-lived-pod" + string(util.NewUUID()) n := itArg.podsPerMinion * minionCount expectNoError(RunRC(c, name, ns, "gcr.io/google_containers/pause:go", n)) podsLaunched += n Logf("Launched %v pods so far...", podsLaunched) err := DeleteRC(c, ns, name) expectNoError(err) } }() } // Wait for all the pods from all the RC's to return. wg.Wait() Logf("%v pods out of %v launched", podsLaunched, itArg.totalPods) }) } </del> })


Question:
The issue is to follow up discussions in : running conformance test with the commonly used tool, sonobuoy, failed because the tool's test runner is lack of permission towards . The original issue was resolved by changing the e2e (conformance) test of to an integration test. Several problems remained: privilege requirement in is outdated. discovery is one of the least-privileged permissions, and is expected to be granted to every authenticated user but is not actually. the result returned by should be part of conformance? 1st and 2nd are straightforward to fix, not sure about 3rd, should we add a separate test or add a verification step in existing one like With the fix of 2nd, e2e for should no longer fail with any test runner. cc - should be reflect the accurate permission requirement discovery permission should be granted to all authenticated users. test should check the result returned by . Inapplicable No response <details</details<details</details<details</details<details</details<details</details<details</details
/sig api-machinery /sig testing
I agree with this. We have conformance tests around things like webhooks and custom resource definitions. I'd recommend rephrasing that as "limits itself to capabilities exposed via APIs (e.g., does not require root on nodes, access to raw network interfaces) and does not require write access to system namespaces (like kube-system)" I'm not sure I agree with this. No binaries Kubernetes provides (that I'm aware of) and nothing in client-go needs to make use of root discovery information. I'd be very slow to expand endpoints included in . Unless we have compelling reasons for people to use and rely on this data, I would lean towards no.
can we fix 1 , that seems that everybody agree and looks like the most clear one? the other sound more contentious
thanks for your comments. Created for 1 and closed the other one.
Thanks all. Agree on this outcome.
/triage accepted

<ins> /* Copyright 2015 Google Inc. All rights reserved. Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. */ package e2e import ( "fmt" "sync" "github.com/GoogleCloudPlatform/kubernetes/pkg/client" "github.com/GoogleCloudPlatform/kubernetes/pkg/fields" "github.com/GoogleCloudPlatform/kubernetes/pkg/labels" "github.com/GoogleCloudPlatform/kubernetes/pkg/util" . "github.com/onsi/ginkgo" . "github.com/onsi/gomega" ) // This test suite can take a long time to run, so by default it is added to // the ginkgo.skip list (see driver.go). // To run this suite you must explicitly ask for it by setting the // -t/--test flag or ginkgo.focus flag. var _ = Describe("Scale", func() { var c *client.Client var minionCount int var RCName string var ns string BeforeEach(func() { var err error c, err = loadClient() expectNoError(err) minions, err := c.Nodes().List(labels.Everything(), fields.Everything()) expectNoError(err) minionCount = len(minions.Items) Expect(minionCount).NotTo(BeZero()) nsForTesting, err := createTestingNS("scale", c) ns = nsForTesting.Name expectNoError(err) }) AfterEach(func() { // Remove any remaining pods from this test if the // replication controller still exists and the replica count // isn't 0.  This means the controller wasn't cleaned up // during the test so clean it up here rc, err := c.ReplicationControllers(ns).Get(RCName) if err == nil && rc.Spec.Replicas != 0 { By("Cleaning up the replication controller") err := DeleteRC(c, ns, RCName) expectNoError(err) } By(fmt.Sprintf("Destroying namespace for this suite %v", ns)) if err := c.Namespaces().Delete(ns); err != nil { Failf("Couldn't delete ns %s", err) } }) type Scalability struct { skip          bool totalPods     int podsPerMinion int rcsPerThread  int } scalabilityTests := []Scalability{ {totalPods: 500, podsPerMinion: 10, rcsPerThread: 5, skip: true}, {totalPods: 500, podsPerMinion: 10, rcsPerThread: 25, skip: true}, } for _, testArg := range scalabilityTests { // # of threads calibrate to totalPods threads := (testArg.totalPods / (testArg.podsPerMinion * testArg.rcsPerThread)) name := fmt.Sprintf( "should be able to launch %v pods, %v per minion, in %v rcs/thread.", testArg.totalPods, testArg.podsPerMinion, testArg.rcsPerThread) if testArg.skip { name = "[Skipped] " + name } itArg := testArg It(name, func() { podsLaunched := 0 var wg sync.WaitGroup wg.Add(threads) // Create queue of pending requests on the api server. for i := 0; i < threads; i++ { go func() { defer GinkgoRecover() defer wg.Done() for i := 0; i < itArg.rcsPerThread; i++ { name := "my-short-lived-pod" + string(util.NewUUID()) n := itArg.podsPerMinion * minionCount expectNoError(RunRC(c, name, ns, "gcr.io/google_containers/pause:go", n)) podsLaunched += n Logf("Launched %v pods so far...", podsLaunched) err := DeleteRC(c, ns, name) expectNoError(err) } }() } // Wait for all the pods from all the RC's to return. wg.Wait() Logf("%v pods out of %v launched", podsLaunched, itArg.totalPods) }) } }) </ins>


Question:
When installing the metrics-server to implement the API and the prometheus-adapter to implement the API, it is possible to make the OpenAPI handler fail to initialize with this error log in apiserver: This will result in kubectl discovery calls to /openapi/v2 to fail with a 503: The OpenAPI handler should not fail to initialize if both and are serving the same path for different API groups/versions. I can provide exact installation steps if needed, however, a high-level repro is: install metrics-server to serve install prometheus-adapter to serve ensure resourceRules is populated in the prometheus-adapter config so that resource metrics are also served by restarting apiserver will result in the OpenAPI failure and 503 responses to /openapi/v2 path No response <details</details<detailsAWS </details<details</details<details</details<details</details<details</details
Please let me know if I should reopen the issue in
/sig api-machinery
/sig instrumentation [metrics apis]
Would you mind taking a look when have time? Thank you^^ /triage accepted
I have a question. should be serving under . Why does an apiservice serving another gvk register paths under ? cc we've made the assumption that an APIService (such as metrics-server or prometheus-adapter) serves only gvks under its own registered group version. I'll do some more investigation but just wondering if prometheus doesn't follow that assumption?
the prometheus-adapter can also be configured to serve and replace the metrics-server by enabling these metrics, However, if the prometheus-adapter fronts and metrics-server fronts , it does seem like the correct behavior would be for prometheus-adapter to serve until an operator updates the APIService to reference prometheus-adapter rather than metrics-server. We're seeing this issue occur for upgrades between 1.27 and 1.28 so it does look this path duplication did not cause the OpenAPI handler to fail on 1.27.
I just upgraded from 1.27 to 1.28 and running into this problem. Some kubectl apply operations fail, and ArgoCD cannot load its custom resources. Any suggested workaround? Would removing the from the prometheus configuration resolve it? Or perhaps disable metrics-server?
Simply looking at the code diff between 1.27 and 1.28 I can't pinpoint the cause. Can I get your exact repro steps? suggests that the conflicting paths should be removed before the merge. We always call this function with
One other question is if this is reproducible by just applying a set of yaml/installations or does it require a cluster upgrade to trigger? Thanks!
hit same problem and we cannot install any other new helm plugins. maybe we need to move forward
Here are verbose repro instructions. An apiserver restart on 1.28 will induce the issue.
Hello. I'm still having some trouble reproducing although I'm not 100% sure if the configuration is correct. I'm trying to repro via kind. afaik installing via helm has prometheus adapter serving . seems to suggest that prometheus adapter is serving under . Applying the update to the configmap per the instructions didn't change the apiservice on my end. Not sure if this is my misconfiguration or intended. I've also tested via integration test that having two openapis serving the same path doesn't cause errors and one will get filtered out. A simple workaround is probably to delete the metrics-server if it is already superseded by the prometheus-adapter.
The is not set up in an resource for us, we only created an APIService with . When I go fetch the openAPI schema served up by the endpoint, it has schema information for in it if that is enabled using . If I remove then the schema fetched from the server doesn't have stuff in it, and the error is resolved. We have been keeping around because I think something uses it directly, or used to. Maybe ? That could have changed But in any case, this problem is quite severe when it happens so it would be nice to fix it as there may be others who do the same update and have to do some deep diving into the logs and all kinds of crazy diagnostics and guesswork to figure it out.
How does the get reached without an APIService? The resources would be unavailable for the apiserver to query and it'll be through something else? I see, adding resources for me doesn't populate the OpenAPI. I wonder if this could be cloud provider specific. I'm totally supportive of fixing, it's just quite difficult to reproduce on my part .
Hmm good question. In our staging cluster I tried bringing back the in the custom metrics server configuration and restarting all the masters, and the problem did not come back, everything seems OK now. So it maybe isn't that easy to reproduce
After updating the configmap, restarting the prometheus-adapter pod to pickup the changes and restarting the apiserver are both required to induce the issue. I have been able to deterministically reproduce this following those steps, please follow up here if you are still having issues.
That's good to hear. I'll need some more help with reproducing it. I've been able to verify that restarting the prometheus adapter pod picks up the configmap changes but restarting the apiserver hasn't caused any crashes for me. I've tested this both on the latest master branch and 1.28.
While I'm yet to fully understand these changes, the 2 PRs below (both of which went into 1.28) seem likely candidates for a regression here: - introduced lazy loading in openAPI v2 handler to load/compute the aggregator spec when requested by client - switched the spec merging function from to any clue if one of the above changes could be causing mischief?
Also from example request at the top, the impact seems to be to the v2 API: Nathan - when you get a chance, could you also confirm if v1 API doesn't run into this?
OpenAPI only supports v2 and v3.
hi, any clue about this issue?
It's possible but I haven't been able to reproduce it. Can I ask if this is happening on cloud providers outside AWS?
Here are the apiservices and relevant pod objects with a working repro from these steps If it's useful, I can provide yamls for these objects in addition to the settings applied in the prometheus-adapter configmap. Can you confirm that the pods backing your prometheus-adapter and metrics-server are running?
I meet this problem
We the problem in GCP as well.
ACK in Alibaba Cloud also meets this problem
We were able to fix the v2 availability by and re-installing the kube-prometheus helm chart. Unfortunately, after restarting the k8s api server, v2 availability is broken again.
yes, I'm running on kind. I'll do some more digging, assuming it's related to those PRs linked by but still haven't pinpointed anything.
I tried to reproduce on my local setup with based on steps + , but I could still get a successful response when I executed . Then I reverted one of the step mentioned in to and waited until the new pod came alive and then did a apiserver restart and I was able to reproduce the same thing on as well i.e; I get the 503 response when I execute following command after the fact. After this point, even if i change it back to and restart the apiserver , the error is persistent. Let me know if this works for you to reproduce ? PS: Also, i want to call out that there is no issue with , its .
Thanks, alright I found a way to reproduce it consistently without restarting the apiserver. Still investigating the root cause. Thanks for the detailed reproduction and
Quick update: This issue was a combination of bugs both in k/k and prometheus adapter. I opened to mitigate on k/k side which should fix the issue. The issue was difficult to reproduce because it requires a very specific ordering of OpenAPI merging to trigger, which is why I suspect many people were able to reproduce after some restarts to kube-apiserver. Prometheus and metrics server serve differing OpenAPIs for the endpoint. Prometheus also doesn't seem to be registering discovery's OpenAPI properly (missing OpenAPI for but having the OpenAPI for whereas it is all present in metrics server. This inconsistency in how prometheus and metrics server handle the OpenAPI surfaced the merging issue.
a little wired question: why do we need to restart kube-apiserver to reproduce this problem?
Tried to reproduce the issue after cherry picking the fix and didn't run into below error. Fix is working as expected.
It can look like restarting prometheus-adapter "fixes" the issue? I am also curious about suggestion of removing the section from the config map works as a temporary workaround until released upstream (we use and cannot delete the apiregistration)? As I understand the fix for this issue is currently in

if err != nil { return nil, "", err } <del> return aggregator.FilterSpecByPathsWithoutSideEffects(result, []string{"/apis/"}), etag, nil </del> <ins> group := specInfo.apiService.Spec.Group version := specInfo.apiService.Spec.Version return aggregator.FilterSpecByPathsWithoutSideEffects(result, []string{"/apis/" + group + "/" + version}), etag, nil </ins> }, cached.Result[*spec.Swagger]{Value: result, Etag: etag, Err: err}) specInfo.spec.Store(filteredResult) return err


Question:
When installing the metrics-server to implement the API and the prometheus-adapter to implement the API, it is possible to make the OpenAPI handler fail to initialize with this error log in apiserver: This will result in kubectl discovery calls to /openapi/v2 to fail with a 503: The OpenAPI handler should not fail to initialize if both and are serving the same path for different API groups/versions. I can provide exact installation steps if needed, however, a high-level repro is: install metrics-server to serve install prometheus-adapter to serve ensure resourceRules is populated in the prometheus-adapter config so that resource metrics are also served by restarting apiserver will result in the OpenAPI failure and 503 responses to /openapi/v2 path No response <details</details<detailsAWS </details<details</details<details</details<details</details<details</details
Please let me know if I should reopen the issue in
/sig api-machinery
/sig instrumentation [metrics apis]
Would you mind taking a look when have time? Thank you^^ /triage accepted
I have a question. should be serving under . Why does an apiservice serving another gvk register paths under ? cc we've made the assumption that an APIService (such as metrics-server or prometheus-adapter) serves only gvks under its own registered group version. I'll do some more investigation but just wondering if prometheus doesn't follow that assumption?
the prometheus-adapter can also be configured to serve and replace the metrics-server by enabling these metrics, However, if the prometheus-adapter fronts and metrics-server fronts , it does seem like the correct behavior would be for prometheus-adapter to serve until an operator updates the APIService to reference prometheus-adapter rather than metrics-server. We're seeing this issue occur for upgrades between 1.27 and 1.28 so it does look this path duplication did not cause the OpenAPI handler to fail on 1.27.
I just upgraded from 1.27 to 1.28 and running into this problem. Some kubectl apply operations fail, and ArgoCD cannot load its custom resources. Any suggested workaround? Would removing the from the prometheus configuration resolve it? Or perhaps disable metrics-server?
Simply looking at the code diff between 1.27 and 1.28 I can't pinpoint the cause. Can I get your exact repro steps? suggests that the conflicting paths should be removed before the merge. We always call this function with
One other question is if this is reproducible by just applying a set of yaml/installations or does it require a cluster upgrade to trigger? Thanks!
hit same problem and we cannot install any other new helm plugins. maybe we need to move forward
Here are verbose repro instructions. An apiserver restart on 1.28 will induce the issue.
Hello. I'm still having some trouble reproducing although I'm not 100% sure if the configuration is correct. I'm trying to repro via kind. afaik installing via helm has prometheus adapter serving . seems to suggest that prometheus adapter is serving under . Applying the update to the configmap per the instructions didn't change the apiservice on my end. Not sure if this is my misconfiguration or intended. I've also tested via integration test that having two openapis serving the same path doesn't cause errors and one will get filtered out. A simple workaround is probably to delete the metrics-server if it is already superseded by the prometheus-adapter.
The is not set up in an resource for us, we only created an APIService with . When I go fetch the openAPI schema served up by the endpoint, it has schema information for in it if that is enabled using . If I remove then the schema fetched from the server doesn't have stuff in it, and the error is resolved. We have been keeping around because I think something uses it directly, or used to. Maybe ? That could have changed But in any case, this problem is quite severe when it happens so it would be nice to fix it as there may be others who do the same update and have to do some deep diving into the logs and all kinds of crazy diagnostics and guesswork to figure it out.
How does the get reached without an APIService? The resources would be unavailable for the apiserver to query and it'll be through something else? I see, adding resources for me doesn't populate the OpenAPI. I wonder if this could be cloud provider specific. I'm totally supportive of fixing, it's just quite difficult to reproduce on my part .
Hmm good question. In our staging cluster I tried bringing back the in the custom metrics server configuration and restarting all the masters, and the problem did not come back, everything seems OK now. So it maybe isn't that easy to reproduce
After updating the configmap, restarting the prometheus-adapter pod to pickup the changes and restarting the apiserver are both required to induce the issue. I have been able to deterministically reproduce this following those steps, please follow up here if you are still having issues.
That's good to hear. I'll need some more help with reproducing it. I've been able to verify that restarting the prometheus adapter pod picks up the configmap changes but restarting the apiserver hasn't caused any crashes for me. I've tested this both on the latest master branch and 1.28.
While I'm yet to fully understand these changes, the 2 PRs below (both of which went into 1.28) seem likely candidates for a regression here: - introduced lazy loading in openAPI v2 handler to load/compute the aggregator spec when requested by client - switched the spec merging function from to any clue if one of the above changes could be causing mischief?
Also from example request at the top, the impact seems to be to the v2 API: Nathan - when you get a chance, could you also confirm if v1 API doesn't run into this?
OpenAPI only supports v2 and v3.
hi, any clue about this issue?
It's possible but I haven't been able to reproduce it. Can I ask if this is happening on cloud providers outside AWS?
Here are the apiservices and relevant pod objects with a working repro from these steps If it's useful, I can provide yamls for these objects in addition to the settings applied in the prometheus-adapter configmap. Can you confirm that the pods backing your prometheus-adapter and metrics-server are running?
I meet this problem
We the problem in GCP as well.
ACK in Alibaba Cloud also meets this problem
We were able to fix the v2 availability by and re-installing the kube-prometheus helm chart. Unfortunately, after restarting the k8s api server, v2 availability is broken again.
yes, I'm running on kind. I'll do some more digging, assuming it's related to those PRs linked by but still haven't pinpointed anything.
I tried to reproduce on my local setup with based on steps + , but I could still get a successful response when I executed . Then I reverted one of the step mentioned in to and waited until the new pod came alive and then did a apiserver restart and I was able to reproduce the same thing on as well i.e; I get the 503 response when I execute following command after the fact. After this point, even if i change it back to and restart the apiserver , the error is persistent. Let me know if this works for you to reproduce ? PS: Also, i want to call out that there is no issue with , its .
Thanks, alright I found a way to reproduce it consistently without restarting the apiserver. Still investigating the root cause. Thanks for the detailed reproduction and
Quick update: This issue was a combination of bugs both in k/k and prometheus adapter. I opened to mitigate on k/k side which should fix the issue. The issue was difficult to reproduce because it requires a very specific ordering of OpenAPI merging to trigger, which is why I suspect many people were able to reproduce after some restarts to kube-apiserver. Prometheus and metrics server serve differing OpenAPIs for the endpoint. Prometheus also doesn't seem to be registering discovery's OpenAPI properly (missing OpenAPI for but having the OpenAPI for whereas it is all present in metrics server. This inconsistency in how prometheus and metrics server handle the OpenAPI surfaced the merging issue.
a little wired question: why do we need to restart kube-apiserver to reproduce this problem?
Tried to reproduce the issue after cherry picking the fix and didn't run into below error. Fix is working as expected.
It can look like restarting prometheus-adapter "fixes" the issue? I am also curious about suggestion of removing the section from the config map works as a temporary workaround until released upstream (we use and cannot delete the apiregistration)? As I understand the fix for this issue is currently in

SwaggerProps: spec.SwaggerProps{ Paths: &spec.Paths{ Paths: map[string]spec.PathItem{ <del> "/apis/apiservicegroup/v1": {}, </del> <ins> "/apis/apiservicegroup/v1/path1": {}, </ins> }, }, },


Question:
When installing the metrics-server to implement the API and the prometheus-adapter to implement the API, it is possible to make the OpenAPI handler fail to initialize with this error log in apiserver: This will result in kubectl discovery calls to /openapi/v2 to fail with a 503: The OpenAPI handler should not fail to initialize if both and are serving the same path for different API groups/versions. I can provide exact installation steps if needed, however, a high-level repro is: install metrics-server to serve install prometheus-adapter to serve ensure resourceRules is populated in the prometheus-adapter config so that resource metrics are also served by restarting apiserver will result in the OpenAPI failure and 503 responses to /openapi/v2 path No response <details</details<detailsAWS </details<details</details<details</details<details</details<details</details
Please let me know if I should reopen the issue in
/sig api-machinery
/sig instrumentation [metrics apis]
Would you mind taking a look when have time? Thank you^^ /triage accepted
I have a question. should be serving under . Why does an apiservice serving another gvk register paths under ? cc we've made the assumption that an APIService (such as metrics-server or prometheus-adapter) serves only gvks under its own registered group version. I'll do some more investigation but just wondering if prometheus doesn't follow that assumption?
the prometheus-adapter can also be configured to serve and replace the metrics-server by enabling these metrics, However, if the prometheus-adapter fronts and metrics-server fronts , it does seem like the correct behavior would be for prometheus-adapter to serve until an operator updates the APIService to reference prometheus-adapter rather than metrics-server. We're seeing this issue occur for upgrades between 1.27 and 1.28 so it does look this path duplication did not cause the OpenAPI handler to fail on 1.27.
I just upgraded from 1.27 to 1.28 and running into this problem. Some kubectl apply operations fail, and ArgoCD cannot load its custom resources. Any suggested workaround? Would removing the from the prometheus configuration resolve it? Or perhaps disable metrics-server?
Simply looking at the code diff between 1.27 and 1.28 I can't pinpoint the cause. Can I get your exact repro steps? suggests that the conflicting paths should be removed before the merge. We always call this function with
One other question is if this is reproducible by just applying a set of yaml/installations or does it require a cluster upgrade to trigger? Thanks!
hit same problem and we cannot install any other new helm plugins. maybe we need to move forward
Here are verbose repro instructions. An apiserver restart on 1.28 will induce the issue.
Hello. I'm still having some trouble reproducing although I'm not 100% sure if the configuration is correct. I'm trying to repro via kind. afaik installing via helm has prometheus adapter serving . seems to suggest that prometheus adapter is serving under . Applying the update to the configmap per the instructions didn't change the apiservice on my end. Not sure if this is my misconfiguration or intended. I've also tested via integration test that having two openapis serving the same path doesn't cause errors and one will get filtered out. A simple workaround is probably to delete the metrics-server if it is already superseded by the prometheus-adapter.
The is not set up in an resource for us, we only created an APIService with . When I go fetch the openAPI schema served up by the endpoint, it has schema information for in it if that is enabled using . If I remove then the schema fetched from the server doesn't have stuff in it, and the error is resolved. We have been keeping around because I think something uses it directly, or used to. Maybe ? That could have changed But in any case, this problem is quite severe when it happens so it would be nice to fix it as there may be others who do the same update and have to do some deep diving into the logs and all kinds of crazy diagnostics and guesswork to figure it out.
How does the get reached without an APIService? The resources would be unavailable for the apiserver to query and it'll be through something else? I see, adding resources for me doesn't populate the OpenAPI. I wonder if this could be cloud provider specific. I'm totally supportive of fixing, it's just quite difficult to reproduce on my part .
Hmm good question. In our staging cluster I tried bringing back the in the custom metrics server configuration and restarting all the masters, and the problem did not come back, everything seems OK now. So it maybe isn't that easy to reproduce
After updating the configmap, restarting the prometheus-adapter pod to pickup the changes and restarting the apiserver are both required to induce the issue. I have been able to deterministically reproduce this following those steps, please follow up here if you are still having issues.
That's good to hear. I'll need some more help with reproducing it. I've been able to verify that restarting the prometheus adapter pod picks up the configmap changes but restarting the apiserver hasn't caused any crashes for me. I've tested this both on the latest master branch and 1.28.
While I'm yet to fully understand these changes, the 2 PRs below (both of which went into 1.28) seem likely candidates for a regression here: - introduced lazy loading in openAPI v2 handler to load/compute the aggregator spec when requested by client - switched the spec merging function from to any clue if one of the above changes could be causing mischief?
Also from example request at the top, the impact seems to be to the v2 API: Nathan - when you get a chance, could you also confirm if v1 API doesn't run into this?
OpenAPI only supports v2 and v3.
hi, any clue about this issue?
It's possible but I haven't been able to reproduce it. Can I ask if this is happening on cloud providers outside AWS?
Here are the apiservices and relevant pod objects with a working repro from these steps If it's useful, I can provide yamls for these objects in addition to the settings applied in the prometheus-adapter configmap. Can you confirm that the pods backing your prometheus-adapter and metrics-server are running?
I meet this problem
We the problem in GCP as well.
ACK in Alibaba Cloud also meets this problem
We were able to fix the v2 availability by and re-installing the kube-prometheus helm chart. Unfortunately, after restarting the k8s api server, v2 availability is broken again.
yes, I'm running on kind. I'll do some more digging, assuming it's related to those PRs linked by but still haven't pinpointed anything.
I tried to reproduce on my local setup with based on steps + , but I could still get a successful response when I executed . Then I reverted one of the step mentioned in to and waited until the new pod came alive and then did a apiserver restart and I was able to reproduce the same thing on as well i.e; I get the 503 response when I execute following command after the fact. After this point, even if i change it back to and restart the apiserver , the error is persistent. Let me know if this works for you to reproduce ? PS: Also, i want to call out that there is no issue with , its .
Thanks, alright I found a way to reproduce it consistently without restarting the apiserver. Still investigating the root cause. Thanks for the detailed reproduction and
Quick update: This issue was a combination of bugs both in k/k and prometheus adapter. I opened to mitigate on k/k side which should fix the issue. The issue was difficult to reproduce because it requires a very specific ordering of OpenAPI merging to trigger, which is why I suspect many people were able to reproduce after some restarts to kube-apiserver. Prometheus and metrics server serve differing OpenAPIs for the endpoint. Prometheus also doesn't seem to be registering discovery's OpenAPI properly (missing OpenAPI for but having the OpenAPI for whereas it is all present in metrics server. This inconsistency in how prometheus and metrics server handle the OpenAPI surfaced the merging issue.
a little wired question: why do we need to restart kube-apiserver to reproduce this problem?
Tried to reproduce the issue after cherry picking the fix and didn't run into below error. Fix is working as expected.
It can look like restarting prometheus-adapter "fixes" the issue? I am also curious about suggestion of removing the section from the config map works as a temporary workaround until released upstream (we use and cannot delete the apiregistration)? As I understand the fix for this issue is currently in

t.Error(err) } <del> expectPath(t, swagger, "/apis/apiservicegroup/v1") </del> <ins> expectPath(t, swagger, "/apis/apiservicegroup/v1/path1") </ins> expectPath(t, swagger, "/apis/apiregistration.k8s.io/v1") t.Log("Update APIService OpenAPI")


Question:
When installing the metrics-server to implement the API and the prometheus-adapter to implement the API, it is possible to make the OpenAPI handler fail to initialize with this error log in apiserver: This will result in kubectl discovery calls to /openapi/v2 to fail with a 503: The OpenAPI handler should not fail to initialize if both and are serving the same path for different API groups/versions. I can provide exact installation steps if needed, however, a high-level repro is: install metrics-server to serve install prometheus-adapter to serve ensure resourceRules is populated in the prometheus-adapter config so that resource metrics are also served by restarting apiserver will result in the OpenAPI failure and 503 responses to /openapi/v2 path No response <details</details<detailsAWS </details<details</details<details</details<details</details<details</details
Please let me know if I should reopen the issue in
/sig api-machinery
/sig instrumentation [metrics apis]
Would you mind taking a look when have time? Thank you^^ /triage accepted
I have a question. should be serving under . Why does an apiservice serving another gvk register paths under ? cc we've made the assumption that an APIService (such as metrics-server or prometheus-adapter) serves only gvks under its own registered group version. I'll do some more investigation but just wondering if prometheus doesn't follow that assumption?
the prometheus-adapter can also be configured to serve and replace the metrics-server by enabling these metrics, However, if the prometheus-adapter fronts and metrics-server fronts , it does seem like the correct behavior would be for prometheus-adapter to serve until an operator updates the APIService to reference prometheus-adapter rather than metrics-server. We're seeing this issue occur for upgrades between 1.27 and 1.28 so it does look this path duplication did not cause the OpenAPI handler to fail on 1.27.
I just upgraded from 1.27 to 1.28 and running into this problem. Some kubectl apply operations fail, and ArgoCD cannot load its custom resources. Any suggested workaround? Would removing the from the prometheus configuration resolve it? Or perhaps disable metrics-server?
Simply looking at the code diff between 1.27 and 1.28 I can't pinpoint the cause. Can I get your exact repro steps? suggests that the conflicting paths should be removed before the merge. We always call this function with
One other question is if this is reproducible by just applying a set of yaml/installations or does it require a cluster upgrade to trigger? Thanks!
hit same problem and we cannot install any other new helm plugins. maybe we need to move forward
Here are verbose repro instructions. An apiserver restart on 1.28 will induce the issue.
Hello. I'm still having some trouble reproducing although I'm not 100% sure if the configuration is correct. I'm trying to repro via kind. afaik installing via helm has prometheus adapter serving . seems to suggest that prometheus adapter is serving under . Applying the update to the configmap per the instructions didn't change the apiservice on my end. Not sure if this is my misconfiguration or intended. I've also tested via integration test that having two openapis serving the same path doesn't cause errors and one will get filtered out. A simple workaround is probably to delete the metrics-server if it is already superseded by the prometheus-adapter.
The is not set up in an resource for us, we only created an APIService with . When I go fetch the openAPI schema served up by the endpoint, it has schema information for in it if that is enabled using . If I remove then the schema fetched from the server doesn't have stuff in it, and the error is resolved. We have been keeping around because I think something uses it directly, or used to. Maybe ? That could have changed But in any case, this problem is quite severe when it happens so it would be nice to fix it as there may be others who do the same update and have to do some deep diving into the logs and all kinds of crazy diagnostics and guesswork to figure it out.
How does the get reached without an APIService? The resources would be unavailable for the apiserver to query and it'll be through something else? I see, adding resources for me doesn't populate the OpenAPI. I wonder if this could be cloud provider specific. I'm totally supportive of fixing, it's just quite difficult to reproduce on my part .
Hmm good question. In our staging cluster I tried bringing back the in the custom metrics server configuration and restarting all the masters, and the problem did not come back, everything seems OK now. So it maybe isn't that easy to reproduce
After updating the configmap, restarting the prometheus-adapter pod to pickup the changes and restarting the apiserver are both required to induce the issue. I have been able to deterministically reproduce this following those steps, please follow up here if you are still having issues.
That's good to hear. I'll need some more help with reproducing it. I've been able to verify that restarting the prometheus adapter pod picks up the configmap changes but restarting the apiserver hasn't caused any crashes for me. I've tested this both on the latest master branch and 1.28.
While I'm yet to fully understand these changes, the 2 PRs below (both of which went into 1.28) seem likely candidates for a regression here: - introduced lazy loading in openAPI v2 handler to load/compute the aggregator spec when requested by client - switched the spec merging function from to any clue if one of the above changes could be causing mischief?
Also from example request at the top, the impact seems to be to the v2 API: Nathan - when you get a chance, could you also confirm if v1 API doesn't run into this?
OpenAPI only supports v2 and v3.
hi, any clue about this issue?
It's possible but I haven't been able to reproduce it. Can I ask if this is happening on cloud providers outside AWS?
Here are the apiservices and relevant pod objects with a working repro from these steps If it's useful, I can provide yamls for these objects in addition to the settings applied in the prometheus-adapter configmap. Can you confirm that the pods backing your prometheus-adapter and metrics-server are running?
I meet this problem
We the problem in GCP as well.
ACK in Alibaba Cloud also meets this problem
We were able to fix the v2 availability by and re-installing the kube-prometheus helm chart. Unfortunately, after restarting the k8s api server, v2 availability is broken again.
yes, I'm running on kind. I'll do some more digging, assuming it's related to those PRs linked by but still haven't pinpointed anything.
I tried to reproduce on my local setup with based on steps + , but I could still get a successful response when I executed . Then I reverted one of the step mentioned in to and waited until the new pod came alive and then did a apiserver restart and I was able to reproduce the same thing on as well i.e; I get the 503 response when I execute following command after the fact. After this point, even if i change it back to and restart the apiserver , the error is persistent. Let me know if this works for you to reproduce ? PS: Also, i want to call out that there is no issue with , its .
Thanks, alright I found a way to reproduce it consistently without restarting the apiserver. Still investigating the root cause. Thanks for the detailed reproduction and
Quick update: This issue was a combination of bugs both in k/k and prometheus adapter. I opened to mitigate on k/k side which should fix the issue. The issue was difficult to reproduce because it requires a very specific ordering of OpenAPI merging to trigger, which is why I suspect many people were able to reproduce after some restarts to kube-apiserver. Prometheus and metrics server serve differing OpenAPIs for the endpoint. Prometheus also doesn't seem to be registering discovery's OpenAPI properly (missing OpenAPI for but having the OpenAPI for whereas it is all present in metrics server. This inconsistency in how prometheus and metrics server handle the OpenAPI surfaced the merging issue.
a little wired question: why do we need to restart kube-apiserver to reproduce this problem?
Tried to reproduce the issue after cherry picking the fix and didn't run into below error. Fix is working as expected.
It can look like restarting prometheus-adapter "fixes" the issue? I am also curious about suggestion of removing the section from the config map works as a temporary workaround until released upstream (we use and cannot delete the apiregistration)? As I understand the fix for this issue is currently in

SwaggerProps: spec.SwaggerProps{ Paths: &spec.Paths{ Paths: map[string]spec.PathItem{ <del> "/apis/apiservicegroup/v2": {}, </del> <ins> "/apis/apiservicegroup/v1/path2": {}, </ins> }, }, },


Question:
When installing the metrics-server to implement the API and the prometheus-adapter to implement the API, it is possible to make the OpenAPI handler fail to initialize with this error log in apiserver: This will result in kubectl discovery calls to /openapi/v2 to fail with a 503: The OpenAPI handler should not fail to initialize if both and are serving the same path for different API groups/versions. I can provide exact installation steps if needed, however, a high-level repro is: install metrics-server to serve install prometheus-adapter to serve ensure resourceRules is populated in the prometheus-adapter config so that resource metrics are also served by restarting apiserver will result in the OpenAPI failure and 503 responses to /openapi/v2 path No response <details</details<detailsAWS </details<details</details<details</details<details</details<details</details
Please let me know if I should reopen the issue in
/sig api-machinery
/sig instrumentation [metrics apis]
Would you mind taking a look when have time? Thank you^^ /triage accepted
I have a question. should be serving under . Why does an apiservice serving another gvk register paths under ? cc we've made the assumption that an APIService (such as metrics-server or prometheus-adapter) serves only gvks under its own registered group version. I'll do some more investigation but just wondering if prometheus doesn't follow that assumption?
the prometheus-adapter can also be configured to serve and replace the metrics-server by enabling these metrics, However, if the prometheus-adapter fronts and metrics-server fronts , it does seem like the correct behavior would be for prometheus-adapter to serve until an operator updates the APIService to reference prometheus-adapter rather than metrics-server. We're seeing this issue occur for upgrades between 1.27 and 1.28 so it does look this path duplication did not cause the OpenAPI handler to fail on 1.27.
I just upgraded from 1.27 to 1.28 and running into this problem. Some kubectl apply operations fail, and ArgoCD cannot load its custom resources. Any suggested workaround? Would removing the from the prometheus configuration resolve it? Or perhaps disable metrics-server?
Simply looking at the code diff between 1.27 and 1.28 I can't pinpoint the cause. Can I get your exact repro steps? suggests that the conflicting paths should be removed before the merge. We always call this function with
One other question is if this is reproducible by just applying a set of yaml/installations or does it require a cluster upgrade to trigger? Thanks!
hit same problem and we cannot install any other new helm plugins. maybe we need to move forward
Here are verbose repro instructions. An apiserver restart on 1.28 will induce the issue.
Hello. I'm still having some trouble reproducing although I'm not 100% sure if the configuration is correct. I'm trying to repro via kind. afaik installing via helm has prometheus adapter serving . seems to suggest that prometheus adapter is serving under . Applying the update to the configmap per the instructions didn't change the apiservice on my end. Not sure if this is my misconfiguration or intended. I've also tested via integration test that having two openapis serving the same path doesn't cause errors and one will get filtered out. A simple workaround is probably to delete the metrics-server if it is already superseded by the prometheus-adapter.
The is not set up in an resource for us, we only created an APIService with . When I go fetch the openAPI schema served up by the endpoint, it has schema information for in it if that is enabled using . If I remove then the schema fetched from the server doesn't have stuff in it, and the error is resolved. We have been keeping around because I think something uses it directly, or used to. Maybe ? That could have changed But in any case, this problem is quite severe when it happens so it would be nice to fix it as there may be others who do the same update and have to do some deep diving into the logs and all kinds of crazy diagnostics and guesswork to figure it out.
How does the get reached without an APIService? The resources would be unavailable for the apiserver to query and it'll be through something else? I see, adding resources for me doesn't populate the OpenAPI. I wonder if this could be cloud provider specific. I'm totally supportive of fixing, it's just quite difficult to reproduce on my part .
Hmm good question. In our staging cluster I tried bringing back the in the custom metrics server configuration and restarting all the masters, and the problem did not come back, everything seems OK now. So it maybe isn't that easy to reproduce
After updating the configmap, restarting the prometheus-adapter pod to pickup the changes and restarting the apiserver are both required to induce the issue. I have been able to deterministically reproduce this following those steps, please follow up here if you are still having issues.
That's good to hear. I'll need some more help with reproducing it. I've been able to verify that restarting the prometheus adapter pod picks up the configmap changes but restarting the apiserver hasn't caused any crashes for me. I've tested this both on the latest master branch and 1.28.
While I'm yet to fully understand these changes, the 2 PRs below (both of which went into 1.28) seem likely candidates for a regression here: - introduced lazy loading in openAPI v2 handler to load/compute the aggregator spec when requested by client - switched the spec merging function from to any clue if one of the above changes could be causing mischief?
Also from example request at the top, the impact seems to be to the v2 API: Nathan - when you get a chance, could you also confirm if v1 API doesn't run into this?
OpenAPI only supports v2 and v3.
hi, any clue about this issue?
It's possible but I haven't been able to reproduce it. Can I ask if this is happening on cloud providers outside AWS?
Here are the apiservices and relevant pod objects with a working repro from these steps If it's useful, I can provide yamls for these objects in addition to the settings applied in the prometheus-adapter configmap. Can you confirm that the pods backing your prometheus-adapter and metrics-server are running?
I meet this problem
We the problem in GCP as well.
ACK in Alibaba Cloud also meets this problem
We were able to fix the v2 availability by and re-installing the kube-prometheus helm chart. Unfortunately, after restarting the k8s api server, v2 availability is broken again.
yes, I'm running on kind. I'll do some more digging, assuming it's related to those PRs linked by but still haven't pinpointed anything.
I tried to reproduce on my local setup with based on steps + , but I could still get a successful response when I executed . Then I reverted one of the step mentioned in to and waited until the new pod came alive and then did a apiserver restart and I was able to reproduce the same thing on as well i.e; I get the 503 response when I execute following command after the fact. After this point, even if i change it back to and restart the apiserver , the error is persistent. Let me know if this works for you to reproduce ? PS: Also, i want to call out that there is no issue with , its .
Thanks, alright I found a way to reproduce it consistently without restarting the apiserver. Still investigating the root cause. Thanks for the detailed reproduction and
Quick update: This issue was a combination of bugs both in k/k and prometheus adapter. I opened to mitigate on k/k side which should fix the issue. The issue was difficult to reproduce because it requires a very specific ordering of OpenAPI merging to trigger, which is why I suspect many people were able to reproduce after some restarts to kube-apiserver. Prometheus and metrics server serve differing OpenAPIs for the endpoint. Prometheus also doesn't seem to be registering discovery's OpenAPI properly (missing OpenAPI for but having the OpenAPI for whereas it is all present in metrics server. This inconsistency in how prometheus and metrics server handle the OpenAPI surfaced the merging issue.
a little wired question: why do we need to restart kube-apiserver to reproduce this problem?
Tried to reproduce the issue after cherry picking the fix and didn't run into below error. Fix is working as expected.
It can look like restarting prometheus-adapter "fixes" the issue? I am also curious about suggestion of removing the section from the config map works as a temporary workaround until released upstream (we use and cannot delete the apiregistration)? As I understand the fix for this issue is currently in

} // Ensure that the if the APIService OpenAPI is updated, the // aggregated OpenAPI is also updated. <ins> expectPath(t, swagger, "/apis/apiservicegroup/v1/path2") expectNoPath(t, swagger, "/apis/apiservicegroup/v1/path1") expectPath(t, swagger, "/apis/apiregistration.k8s.io/v1") } // Tests that an APIService that registers OpenAPI will only have the OpenAPI // for its specific group version served registered. // See https://github.com/kubernetes/kubernetes/pull/123570 for full context. func TestAPIServiceOpenAPIServiceMismatch(t *testing.T) { mux := http.NewServeMux() var delegationHandlers []http.Handler delegate1 := &openAPIHandler{openapi: &spec.Swagger{ SwaggerProps: spec.SwaggerProps{ Paths: &spec.Paths{ Paths: map[string]spec.PathItem{ "/apis/foo/v1": {}, }, }, }, }} delegationHandlers = append(delegationHandlers, delegate1) s := buildAndRegisterSpecAggregator(delegationHandlers, mux) apiService := &v1.APIService{ Spec: v1.APIServiceSpec{ Group:   "apiservicegroup", Version: "v1", Service: &v1.ServiceReference{Name: "dummy"}, }, } apiService.Name = "apiservice" apiService2 := &v1.APIService{ Spec: v1.APIServiceSpec{ Group:   "apiservicegroup", Version: "v2", Service: &v1.ServiceReference{Name: "dummy2"}, }, } apiService2.Name = "apiservice2" handler := &openAPIHandler{openapi: &spec.Swagger{ SwaggerProps: spec.SwaggerProps{ Paths: &spec.Paths{ Paths: map[string]spec.PathItem{ "/apis/apiservicegroup/v1": {}, }, }, }, }} handler2 := &openAPIHandler{openapi: &spec.Swagger{ SwaggerProps: spec.SwaggerProps{ Paths: &spec.Paths{ Paths: map[string]spec.PathItem{ "/apis/a":                  {}, "/apis/apiservicegroup/v1": {}, "/apis/apiservicegroup/v2": {}, }, }, }, }} if err := s.AddUpdateAPIService(apiService, handler); err != nil { t.Error(err) } if err := s.UpdateAPIServiceSpec(apiService.Name); err != nil { t.Error(err) } if err := s.AddUpdateAPIService(apiService2, handler2); err != nil { t.Error(err) } if err := s.UpdateAPIServiceSpec(apiService2.Name); err != nil { t.Error(err) } swagger, err := fetchOpenAPI(mux) if err != nil { t.Error(err) } expectPath(t, swagger, "/apis/apiservicegroup/v1") </ins> expectPath(t, swagger, "/apis/apiservicegroup/v2") <ins> expectPath(t, swagger, "/apis/apiregistration.k8s.io/v1") t.Logf("Remove APIService %s", apiService.Name) s.RemoveAPIService(apiService.Name) swagger, err = fetchOpenAPI(mux) if err != nil { t.Error(err) } // Ensure that the if the APIService is added then removed, the OpenAPI disappears from the aggregated OpenAPI as well. </ins> expectNoPath(t, swagger, "/apis/apiservicegroup/v1") expectPath(t, swagger, "/apis/apiregistration.k8s.io/v1") }


Question:
When installing the metrics-server to implement the API and the prometheus-adapter to implement the API, it is possible to make the OpenAPI handler fail to initialize with this error log in apiserver: This will result in kubectl discovery calls to /openapi/v2 to fail with a 503: The OpenAPI handler should not fail to initialize if both and are serving the same path for different API groups/versions. I can provide exact installation steps if needed, however, a high-level repro is: install metrics-server to serve install prometheus-adapter to serve ensure resourceRules is populated in the prometheus-adapter config so that resource metrics are also served by restarting apiserver will result in the OpenAPI failure and 503 responses to /openapi/v2 path No response <details</details<detailsAWS </details<details</details<details</details<details</details<details</details
Please let me know if I should reopen the issue in
/sig api-machinery
/sig instrumentation [metrics apis]
Would you mind taking a look when have time? Thank you^^ /triage accepted
I have a question. should be serving under . Why does an apiservice serving another gvk register paths under ? cc we've made the assumption that an APIService (such as metrics-server or prometheus-adapter) serves only gvks under its own registered group version. I'll do some more investigation but just wondering if prometheus doesn't follow that assumption?
the prometheus-adapter can also be configured to serve and replace the metrics-server by enabling these metrics, However, if the prometheus-adapter fronts and metrics-server fronts , it does seem like the correct behavior would be for prometheus-adapter to serve until an operator updates the APIService to reference prometheus-adapter rather than metrics-server. We're seeing this issue occur for upgrades between 1.27 and 1.28 so it does look this path duplication did not cause the OpenAPI handler to fail on 1.27.
I just upgraded from 1.27 to 1.28 and running into this problem. Some kubectl apply operations fail, and ArgoCD cannot load its custom resources. Any suggested workaround? Would removing the from the prometheus configuration resolve it? Or perhaps disable metrics-server?
Simply looking at the code diff between 1.27 and 1.28 I can't pinpoint the cause. Can I get your exact repro steps? suggests that the conflicting paths should be removed before the merge. We always call this function with
One other question is if this is reproducible by just applying a set of yaml/installations or does it require a cluster upgrade to trigger? Thanks!
hit same problem and we cannot install any other new helm plugins. maybe we need to move forward
Here are verbose repro instructions. An apiserver restart on 1.28 will induce the issue.
Hello. I'm still having some trouble reproducing although I'm not 100% sure if the configuration is correct. I'm trying to repro via kind. afaik installing via helm has prometheus adapter serving . seems to suggest that prometheus adapter is serving under . Applying the update to the configmap per the instructions didn't change the apiservice on my end. Not sure if this is my misconfiguration or intended. I've also tested via integration test that having two openapis serving the same path doesn't cause errors and one will get filtered out. A simple workaround is probably to delete the metrics-server if it is already superseded by the prometheus-adapter.
The is not set up in an resource for us, we only created an APIService with . When I go fetch the openAPI schema served up by the endpoint, it has schema information for in it if that is enabled using . If I remove then the schema fetched from the server doesn't have stuff in it, and the error is resolved. We have been keeping around because I think something uses it directly, or used to. Maybe ? That could have changed But in any case, this problem is quite severe when it happens so it would be nice to fix it as there may be others who do the same update and have to do some deep diving into the logs and all kinds of crazy diagnostics and guesswork to figure it out.
How does the get reached without an APIService? The resources would be unavailable for the apiserver to query and it'll be through something else? I see, adding resources for me doesn't populate the OpenAPI. I wonder if this could be cloud provider specific. I'm totally supportive of fixing, it's just quite difficult to reproduce on my part .
Hmm good question. In our staging cluster I tried bringing back the in the custom metrics server configuration and restarting all the masters, and the problem did not come back, everything seems OK now. So it maybe isn't that easy to reproduce
After updating the configmap, restarting the prometheus-adapter pod to pickup the changes and restarting the apiserver are both required to induce the issue. I have been able to deterministically reproduce this following those steps, please follow up here if you are still having issues.
That's good to hear. I'll need some more help with reproducing it. I've been able to verify that restarting the prometheus adapter pod picks up the configmap changes but restarting the apiserver hasn't caused any crashes for me. I've tested this both on the latest master branch and 1.28.
While I'm yet to fully understand these changes, the 2 PRs below (both of which went into 1.28) seem likely candidates for a regression here: - introduced lazy loading in openAPI v2 handler to load/compute the aggregator spec when requested by client - switched the spec merging function from to any clue if one of the above changes could be causing mischief?
Also from example request at the top, the impact seems to be to the v2 API: Nathan - when you get a chance, could you also confirm if v1 API doesn't run into this?
OpenAPI only supports v2 and v3.
hi, any clue about this issue?
It's possible but I haven't been able to reproduce it. Can I ask if this is happening on cloud providers outside AWS?
Here are the apiservices and relevant pod objects with a working repro from these steps If it's useful, I can provide yamls for these objects in addition to the settings applied in the prometheus-adapter configmap. Can you confirm that the pods backing your prometheus-adapter and metrics-server are running?
I meet this problem
We the problem in GCP as well.
ACK in Alibaba Cloud also meets this problem
We were able to fix the v2 availability by and re-installing the kube-prometheus helm chart. Unfortunately, after restarting the k8s api server, v2 availability is broken again.
yes, I'm running on kind. I'll do some more digging, assuming it's related to those PRs linked by but still haven't pinpointed anything.
I tried to reproduce on my local setup with based on steps + , but I could still get a successful response when I executed . Then I reverted one of the step mentioned in to and waited until the new pod came alive and then did a apiserver restart and I was able to reproduce the same thing on as well i.e; I get the 503 response when I execute following command after the fact. After this point, even if i change it back to and restart the apiserver , the error is persistent. Let me know if this works for you to reproduce ? PS: Also, i want to call out that there is no issue with , its .
Thanks, alright I found a way to reproduce it consistently without restarting the apiserver. Still investigating the root cause. Thanks for the detailed reproduction and
Quick update: This issue was a combination of bugs both in k/k and prometheus adapter. I opened to mitigate on k/k side which should fix the issue. The issue was difficult to reproduce because it requires a very specific ordering of OpenAPI merging to trigger, which is why I suspect many people were able to reproduce after some restarts to kube-apiserver. Prometheus and metrics server serve differing OpenAPIs for the endpoint. Prometheus also doesn't seem to be registering discovery's OpenAPI properly (missing OpenAPI for but having the OpenAPI for whereas it is all present in metrics server. This inconsistency in how prometheus and metrics server handle the OpenAPI surfaced the merging issue.
a little wired question: why do we need to restart kube-apiserver to reproduce this problem?
Tried to reproduce the issue after cherry picking the fix and didn't run into below error. Fix is working as expected.
It can look like restarting prometheus-adapter "fixes" the issue? I am also curious about suggestion of removing the section from the config map works as a temporary workaround until released upstream (we use and cannot delete the apiregistration)? As I understand the fix for this issue is currently in

apiServiceSuccess := &v1.APIService{ Spec: v1.APIServiceSpec{ <ins> Group:   "success", Version: "v1", </ins> Service: &v1.ServiceReference{Name: "dummy2"}, }, }