Running Percona XtraDB Cluster in a Docker Container

Docker images of Percona XtraDB Cluster are hosted publicly on Docker Hub at https://hub.docker.com/r/percona/percona-xtradb-cluster/.

For more information about using Docker, see the Docker Docs. Make sure that you are using the latest version of Docker. The ones provided via apt and yum may be outdated and cause errors.

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By default, Docker pulls the image from Docker Hub if the image is not available locally. The image contains only the most essential Percona XtraDB Cluster binaries. Utilities included in a Percona Server for MySQL or MySQL installation might be missing from this image.

The following procedure describes how to set up a simple 3-node cluster for evaluation and testing purposes. Do not use these instructions in a production environment because the MySQL certificates generated in this procedure are self-signed. For a production environment, you should generate and store the certificates to be used by Docker.

In this procedure, all of the nodes run Percona XtraDB Cluster 8.4 in separate containers on one host:

1. Create a ~/pxc-docker-test/config directory.

2. Create a custom.cnf file with the following contents, and place the file in the new directory:

   [mysqld]
   ssl-ca = /cert/ca.pem
   ssl-cert = /cert/server-cert.pem
   ssl-key = /cert/server-key.pem
   
   [client]
   ssl-ca = /cert/ca.pem
   ssl-cert = /cert/client-cert.pem
   ssl-key = /cert/client-key.pem
   
   [sst]
   encrypt = 4
   ssl-ca = /cert/ca.pem
   ssl-cert = /cert/server-cert.pem
   ssl-key = /cert/server-key.pem
   

3. Create a cert directory and generate self-signed SSL certificates on the host node:

   $ mkdir -m 777 -p ~/pxc-docker-test/cert
   docker run --name pxc-cert --rm -v ~/pxc-docker-test/cert:/cert
   percona/percona-xtradb-cluster:8.4 mysql_ssl_rsa_setup -d /cert
   

4. Create a Docker network:

   docker network create pxc-network
   

5. Bootstrap the cluster (create the first node):

   docker run -d \
     -e MYSQL_ROOT_PASSWORD=test1234# \
     -e CLUSTER_NAME=pxc-cluster1 \
     --name=pxc-node1 \
     --net=pxc-network \
     -v ~/pxc-docker-test/cert:/cert \
     -v ~/pxc-docker-test/config:/etc/percona-xtradb-cluster.conf.d \
     percona/percona-xtradb-cluster:8.4
   

6. Join the second node:

   docker run -d \
     -e MYSQL_ROOT_PASSWORD=test1234# \
     -e CLUSTER_NAME=pxc-cluster1 \
     -e CLUSTER_JOIN=pxc-node1 \
     --name=pxc-node2 \
     --net=pxc-network \
     -v ~/pxc-docker-test/cert:/cert \
     -v ~/pxc-docker-test/config:/etc/percona-xtradb-cluster.conf.d \
     percona/percona-xtradb-cluster:8.4
   

7. Join the third node:

   docker run -d \
     -e MYSQL_ROOT_PASSWORD=test1234# \
     -e CLUSTER_NAME=pxc-cluster1 \
     -e CLUSTER_JOIN=pxc-node1 \
     --name=pxc-node3 \
     --net=pxc-network \
     -v ~/pxc-docker-test/cert:/cert \
     -v ~/pxc-docker-test/config:/etc/percona-xtradb-cluster.conf.d \
     percona/percona-xtradb-cluster:8.4
   

To verify the cluster is available, do the following:

1. Access the MySQL client. For example, on the first node:

   $ sudo docker exec -it pxc-node1 /usr/bin/mysql -uroot -ptest1234#
   

   Expected output

   mysql: [Warning] Using a password on the command line interface can be insecure.
   Welcome to the MySQL monitor.  Commands end with ; or \g.
   Your MySQL connection id is 12
   ...
   You are enforcing ssl connection via unix socket. Please consider
   switching ssl off as it does not make connection via unix socket
   any more secure
   
   mysql>
   

2. View the wsrep status variables:

   mysql> show status like 'wsrep%';
   

   Expected output

   +------------------------------+-------------------------------------------------+
   | Variable_name                | Value                                           |
   +------------------------------+-------------------------------------------------+
   | wsrep_local_state_uuid       | 625318e2-9e1c-11e7-9d07-aee70d98d8ac            |
   ...
   | wsrep_local_state_comment    | Synced                                          |
   ...
   | wsrep_incoming_addresses     | 172.18.0.2:3306,172.18.0.3:3306,172.18.0.4:3306 |
   ...
   | wsrep_cluster_conf_id        | 3                                               |
   | wsrep_cluster_size           | 3                                               |
   | wsrep_cluster_state_uuid     | 625318e2-9e1c-11e7-9d07-aee70d98d8ac            |
   | wsrep_cluster_status         | Primary                                         |
   | wsrep_connected              | ON                                              |
   ...
   | wsrep_ready                  | ON                                              |
   +------------------------------+-------------------------------------------------+
   59 rows in set (0.02 sec)