# ZooKeeper Monitor Guide * [New Metrics System](#Metrics-System) * [Metrics](#Metrics) * [Prometheus](#Prometheus) * [Alerting with Prometheus](#Alerting) * [Grafana](#Grafana) * [InfluxDB](#influxdb) * [JMX](#JMX) * [Four letter words](#four-letter-words) ## New Metrics System The feature:`New Metrics System` has been available since 3.6.0 which provides the abundant metrics to help users monitor the ZooKeeper on the topic: znode, network, disk, quorum, leader election, client, security, failures, watch/session, requestProcessor, and so forth. ### Metrics All the metrics are included in the `ServerMetrics.java`. ### Pre-requisites: - Enable the `Prometheus MetricsProvider` by setting the following in `zoo.cfg`: ```conf metricsProvider.className=org.apache.zookeeper.metrics.prometheus.PrometheusMetricsProvider ``` - The port for Prometheus metrics can be configured using: ```conf metricsProvider.httpPort=7000 # Default port is 7000 ``` #### Enabling HTTPS for Prometheus Metrics: ZooKeeper also supports SSL for Prometheus metrics, which provides secure data transmission. To enable this, configure an HTTPS port and set up SSL certificates as follows: - Define the HTTPS port: ```conf metricsProvider.httpsPort=4443 ``` - Configure the SSL key store (holds the server’s private key and certificates): ```conf metricsProvider.ssl.keyStore.location=/path/to/keystore.jks metricsProvider.ssl.keyStore.password=your_keystore_password metricsProvider.ssl.keyStore.type=jks # Default is JKS ``` - Configure the SSL trust store (used to verify client certificates): ```conf metricsProvider.ssl.trustStore.location=/path/to/truststore.jks metricsProvider.ssl.trustStore.password=your_truststore_password metricsProvider.ssl.trustStore.type=jks # Default is JKS ``` - **Note**: You can enable both HTTP and HTTPS simultaneously by defining both ports: ```conf metricsProvider.httpPort=7000 metricsProvider.httpsPort=4443 ``` ### Prometheus - Running a [Prometheus](https://prometheus.io/) monitoring service is the easiest way to ingest and record ZooKeeper's metrics. - Install Prometheus: Go to the official website download [page](https://prometheus.io/download/), download the latest release. - Set Prometheus's scraper to target the ZooKeeper cluster endpoints: ```bash cat > /tmp/test-zk.yaml <> /tmp/test-zk.log 2>&1 & ``` - Now Prometheus will scrape zk metrics every 10 seconds. ### Alerting with Prometheus - We recommend that you read [Prometheus Official Alerting Page](https://prometheus.io/docs/practices/alerting/) to explore some principles of alerting - We recommend that you use [Prometheus Alertmanager](https://www.prometheus.io/docs/alerting/latest/alertmanager/) which can help users to receive alerting email or instant message(by webhook) in a more convenient way - We provide an alerting example where these metrics should be taken a special attention. Note: this is for your reference only, and you need to adjust them according to your actual situation and resource environment use ./promtool check rules rules/zk.yml to check the correctness of the config file cat rules/zk.yml groups: - name: zk-alert-example rules: - alert: ZooKeeper server is down expr: up == 0 for: 1m labels: severity: critical annotations: summary: "Instance {{ $labels.instance }} ZooKeeper server is down" description: "{{ $labels.instance }} of job {{$labels.job}} ZooKeeper server is down: [{{ $value }}]." - alert: create too many znodes expr: znode_count > 1000000 for: 1m labels: severity: warning annotations: summary: "Instance {{ $labels.instance }} create too many znodes" description: "{{ $labels.instance }} of job {{$labels.job}} create too many znodes: [{{ $value }}]." - alert: create too many connections expr: num_alive_connections > 50 # suppose we use the default maxClientCnxns: 60 for: 1m labels: severity: warning annotations: summary: "Instance {{ $labels.instance }} create too many connections" description: "{{ $labels.instance }} of job {{$labels.job}} create too many connections: [{{ $value }}]." - alert: znode total occupied memory is too big expr: approximate_data_size /1024 /1024 > 1 * 1024 # more than 1024 MB(1 GB) for: 1m labels: severity: warning annotations: summary: "Instance {{ $labels.instance }} znode total occupied memory is too big" description: "{{ $labels.instance }} of job {{$labels.job}} znode total occupied memory is too big: [{{ $value }}] MB." - alert: set too many watch expr: watch_count > 10000 for: 1m labels: severity: warning annotations: summary: "Instance {{ $labels.instance }} set too many watch" description: "{{ $labels.instance }} of job {{$labels.job}} set too many watch: [{{ $value }}]." - alert: a leader election happens expr: increase(election_time_count[5m]) > 0 for: 1m labels: severity: warning annotations: summary: "Instance {{ $labels.instance }} a leader election happens" description: "{{ $labels.instance }} of job {{$labels.job}} a leader election happens: [{{ $value }}]." - alert: open too many files expr: open_file_descriptor_count > 300 for: 1m labels: severity: warning annotations: summary: "Instance {{ $labels.instance }} open too many files" description: "{{ $labels.instance }} of job {{$labels.job}} open too many files: [{{ $value }}]." - alert: fsync time is too long expr: rate(fsynctime_sum[1m]) > 100 for: 1m labels: severity: warning annotations: summary: "Instance {{ $labels.instance }} fsync time is too long" description: "{{ $labels.instance }} of job {{$labels.job}} fsync time is too long: [{{ $value }}]." - alert: take snapshot time is too long expr: rate(snapshottime_sum[5m]) > 100 for: 1m labels: severity: warning annotations: summary: "Instance {{ $labels.instance }} take snapshot time is too long" description: "{{ $labels.instance }} of job {{$labels.job}} take snapshot time is too long: [{{ $value }}]." - alert: avg latency is too high expr: avg_latency > 100 for: 1m labels: severity: warning annotations: summary: "Instance {{ $labels.instance }} avg latency is too high" description: "{{ $labels.instance }} of job {{$labels.job}} avg latency is too high: [{{ $value }}]." - alert: JvmMemoryFillingUp expr: jvm_memory_bytes_used / jvm_memory_bytes_max{area="heap"} > 0.8 for: 5m labels: severity: warning annotations: summary: "JVM memory filling up (instance {{ $labels.instance }})" description: "JVM memory is filling up (> 80%)\n labels: {{ $labels }} value = {{ $value }}\n" ### Grafana - Grafana has built-in Prometheus support; just add a Prometheus data source: ```bash Name: test-zk Type: Prometheus Url: http://localhost:9090 Access: proxy ``` - Then download and import the default ZooKeeper dashboard [template](https://grafana.com/grafana/dashboards/10465) and customize. - Users can ask for Grafana dashboard account if having any good improvements by writing a email to **dev@zookeeper.apache.org**. ### InfluxDB InfluxDB is an open source time series data that is often used to store metrics from Zookeeper. You can [download](https://portal.influxdata.com/downloads/) the open source version or create a [free](https://cloud2.influxdata.com/signup) account on InfluxDB Cloud. In either case, configure the [Apache Zookeeper Telegraf plugin](https://www.influxdata.com/integration/apache-zookeeper/) to start collecting and storing metrics from your Zookeeper clusters into your InfluxDB instance. There is also an [Apache Zookeeper InfluxDB template](https://www.influxdata.com/influxdb-templates/zookeeper-monitor/) that includes the Telegraf configurations and a dashboard to get you set up right away. ## JMX More details can be found in [here](http://zookeeper.apache.org/doc/current/zookeeperJMX.html) ## Four letter words More details can be found in [here](http://zookeeper.apache.org/doc/current/zookeeperAdmin.html#sc_zkCommands)