Watch the video

Here is a three-minute video that shows how to set up a three-node cluster for mysql and add more capacity on the fly:

Step 1: Create a storage volume for mysql

To create a highly available storage volume for mysql, run the following command and note the returned volume ID. You will need the volume ID when you start the mysql container in the next step.

# docker volume create -d pxd --name mysql_volume --opt \
        size=4 --opt block_size=64 --opt repl=3 --opt fs=ext4

That command creates a volume called mysql_volume. This volume has a replication factor of 3, which means that the data will be protected on 3 separate nodes. We will use this volume to protect the mysql instances data.

Step 2: Start the mysql container

To start the mysql container, run the following command.

# docker run -p 3306:3306                           \
        --host localhost                            \
        --name pxmysql                              \
        -e MYSQL_ROOT_PASSWORD=password             \
        -v mysql_volume:/var/lib/mysql -d mysql

Note the volume binding done via -v mysql_volume:/var/lib/mysql. This causes the Portworx mysql_volume to get bind mounted at /var/lib/mysql, which is where the mysql Docker container stores it’s data.

Your mysql container is now available for use at port 3306.

Step 3: Use pxctl to create snaps of your mysql volume

To demonstrate the capabilities of the SAN-like functionality offered by Portworx, create a snapshot of a mysql volume.

  1. Create a database and a demo table in your mysql container.

    # mysql --user=root --password=password
    MySQL [(none)]> create database pxdemo;
    Query OK, 1 row affected (0.00 sec)
    MySQL [(none)]> use pxdemo;
    Database changed
    MySQL [pxdemo]> create table grapevine (counter int unsigned);
    Query OK, 0 rows affected (0.04 sec)
    MySQL [pxdemo]> quit;
    Bye
    
  2. Create a snapshot of this database using pxctl.

    # /opt/pwx/bin/pxctl snap create 8927336170128555
    Volume successfully snapped:  1483421664452964115
    
  3. Note the snapshot volume ID. Use this to launch a new instance of mysql. Since you already have mysql running, you can go to another node in your cluster, or stop the original mysql instance.

    # docker run -p 3306:3306 --volume-driver=pxd 				\
                         --name pxmysqlclone                 \
                         -e MYSQL_ROOT_PASSWORD=password     \
                         -v 1483421664452964115:/var/lib/mysql -d mysql
    
  4. Verify that the database shows the cloned tables in the new mysql instance.

# mysql --user=root --password=password
MySQL [(none)]> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| pxdemo             |
| sys                |
+--------------------+
5 rows in set (0.00 sec)
MySQL [(none)]> use pxdemo;

Database changed
MySQL [pxdemo]> show tables;
+------------------+
| Tables_in_pxdemo |
+------------------+
| grapevine        |
+------------------+
1 rows in set (0.00 sec)
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