# 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/](https://hub.docker.com/r/percona/percona-xtradb-cluster/).

For more information about using Docker, see the [Docker Docs](https://docs.docker.com/). Make
sure that you are using the latest version of Docker. The ones
provided via `apt` and `yum` may be outdated and cause errors.

We gather [Telemetry data] in the Percona packages and Docker images.

!!! note

    By default, Docker pulls the image from Docker Hub if the image is not
    available locally.

    The image contains only the most essential binaries for Percona XtraDB Cluster to
    run. Some utilities included in a Percona Server for MySQL or MySQL
    installation might be missing from the Percona XtraDB Cluster Docker 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 8.0 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:

    ```{.text .no-copy}
    [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:

    ```{.bash data-prompt="$"}
    $ mkdir -m 777 -p ~/pxc-docker-test/cert
    docker run --name pxc-cert --rm -v ~/pxc-docker-test/cert:/cert
    percona/percona-xtradb-cluster:8.0 mysql_ssl_rsa_setup -d /cert
    ```

4. Create a Docker network:

    ```{.bash data-prompt="$"}
    $ docker network create pxc-network
    ```

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

    ```{.bash data-prompt="$"}
    $ 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:8.0
    ```

6. Join the second node:

    ```{.bash data-prompt="$"}
    $ 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:8.0
    ```

7. Join the third node:

    ```{.bash data-prompt="$"}
    $ 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:8.0
    ```

To verify the cluster is available, do the following:

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

    ```{.bash data-prompt="$"}
    $ sudo docker exec -it pxc-node1 /usr/bin/mysql -uroot -ptest1234#
    ```

    ??? example "Expected output"

        ```{.text .no-copy}
        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:

    ```{.bash data-prompt="mysql>"}
    mysql> show status like 'wsrep%';
    ```

    ??? example "Expected output"

        ```{.text .no-copy}
        +------------------------------+-------------------------------------------------+
        | 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)
        ```

[Telemetry data]: telemetry.md