text stringlengths 0 59.1k |
|---|
node: pxc-node1 |
unit: pxc-cluster |
spec: |
containers: |
- resources: |
limits: |
cpu: 0.3 |
image: capttofu/percona_xtradb_cluster_5_6:beta |
name: pxc-node1 |
ports: |
- containerPort: 3306 |
- containerPort: 4444 |
- containerPort: 4567 |
- containerPort: 4568 |
env: |
- name: GALERA_CLUSTER |
value: "true" |
- name: WSREP_CLUSTER_ADDRESS |
value: gcomm:// |
- name: WSREP_SST_USER |
value: sst |
- name: WSREP_SST_PASSWORD |
value: sst |
- name: MYSQL_USER |
value: mysql |
- name: MYSQL_PASSWORD |
value: mysql |
- name: MYSQL_ROOT_PASSWORD |
value: c-krit |
<|endoftext|> |
# source: k8s_examples/_archived/storage/mysql-galera/README.md type: docs |
## Galera Replication for MySQL on Kubernetes |
This document explains a simple demonstration example of running MySQL synchronous replication using Galera, specifically, Percona XtraDB cluster. The example is simplistic and used a fixed number (3) of nodes but the idea can be built upon and made more dynamic as Kubernetes matures. |
### Prerequisites |
This example assumes that you have a Kubernetes cluster installed and running, and that you have installed the ```kubectl``` command line tool somewhere in your path. Please see the [getting started](https://kubernetes.io/docs/getting-started-guides/) for installation instructions for your platform. |
Also, this example requires the image found in the ```image``` directory. For your convenience, it is built and available on Docker's public image repository as ```capttofu/percona_xtradb_cluster_5_6```. It can also be built which would merely require that the image in the pod or replication controller files is updated... |
This example was tested on OS X with a Galera cluster running on VMWare using the fine repo developed by Paulo Pires [https://github.com/pires/kubernetes-vagrant-coreos-cluster] and client programs built for OS X. |
### Basic concept |
The basic idea is this: three replication controllers with a single pod, corresponding services, and a single overall service to connect to all three nodes. One of the important design goals of MySQL replication and/or clustering is that you don't want a single-point-of-failure, hence the need to distribute each node o... |
By defaults, there are only three pods (hence replication controllers) for this cluster. This number can be increased using the variable NUM_NODES, specified in the replication controller configuration file. It's important to know the number of nodes must always be odd. |
When the replication controller is created, it results in the corresponding container to start, run an entrypoint script that installs the MySQL system tables, set up users, and build up a list of servers that is used with the galera parameter ```wsrep_cluster_address```. This is a list of running nodes that galera us... |
Note: Kubernetes best-practices is to pre-create the services for each controller, and the configuration files which contain the service and replication controller for each node, when created, will result in both a service and replication controller running for the given node. An important thing to know is that it's im... |
First, create the overall cluster service that will be used to connect to the cluster: |
```kubectl create -f examples/storage/mysql-galera/pxc-cluster-service.yaml``` |
Create the service and replication controller for the first node: |
```kubectl create -f examples/storage/mysql-galera/pxc-node1.yaml``` |
### Create services and controllers for the remaining nodes |
Repeat the same previous steps for ```pxc-node2``` and ```pxc-node3```. |
When completed, you should be able to connect with a MySQL client to the IP address |
service ```pxc-cluster``` to find a working cluster. |
### An example of creating a cluster |
Shown below are examples of Using ```kubectl``` from within the ```./examples/storage/mysql-galera``` directory, the status of the launched replication controllers and services can be confirmed: |
``` |
$ kubectl create -f examples/storage/mysql-galera/pxc-cluster-service.yaml |
services/pxc-cluster |
$ kubectl create -f examples/storage/mysql-galera/pxc-node1.yaml |
services/pxc-node1 |
replicationcontrollers/pxc-node1 |
$ kubectl create -f examples/storage/mysql-galera/pxc-node2.yaml |
services/pxc-node2 |
replicationcontrollers/pxc-node2 |
$ kubectl create -f examples/storage/mysql-galera/pxc-node3.yaml |
services/pxc-node3 |
replicationcontrollers/pxc-node3 |
``` |
### Confirm a running cluster |
Verify everything is running: |
``` |
$ kubectl get rc,pods,services |
CONTROLLER CONTAINER(S) IMAGE(S) SELECTOR REPLICAS |
pxc-node1 pxc-node1 capttofu/percona_xtradb_cluster_5_6:beta name=pxc-node1 1 |
pxc-node2 pxc-node2 capttofu/percona_xtradb_cluster_5_6:beta name=pxc-node2 1 |
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