Playing with Percona XtraDB Cluster in Docker

Like any good, thus lazy, engineer I don’t like to start things manually. Creating directories, configuration files, specify paths, ports via command line is too boring. I wrote already how I survive in case when I need to start MySQL server (here). There is also the MySQL Sandbox which can be used for the same purpose.

But what to do if you want to start Percona XtraDB Cluster this way? Fortunately we, at Percona, have engineers who created automation solution for starting PXC. This solution uses Docker. To explore it you need:

1. Clone the pxc-docker repository:
   git clone https://github.com/percona/pxc-docker
2. Install Docker Compose as described here
3. cd pxc-docker/docker-bld
4. Follow instructions from the README file:
   

   a) ./docker-gen.sh 5.6    (docker-gen.sh takes a PXC branch as argument, 5.6 is default, and it looks for it on github.com/percona/percona-xtradb-cluster)

   b) Optional: docker-compose build (if you see it is not updating with changes).

   c) docker-compose scale bootstrap=1 members=2 for a 3 node cluster

5. Check which ports assigned to containers:
   
   Shell

   $docker port dockerbld_bootstrap_1 3306 0.0.0.0:32768 $docker port dockerbld_members_1 4567 0.0.0.0:32772 $docker port dockerbld_members_2 4568 0.0.0.0:32776

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   $docker port dockerbld_bootstrap_1 3306 0.0.0.0:32768 $docker port dockerbld_members_1 4567 0.0.0.0:32772 $docker port dockerbld_members_2 4568 0.0.0.0:32776

   
   Now you can connect to MySQL clients as usual:
   
   MySQL

   $mysql -h 0.0.0.0 -P 32768 -uroot Welcome to the MySQL monitor.  Commands end with ; or g. Your MySQL connection id is 10 Server version: 5.6.21-70.1 MySQL Community Server (GPL), wsrep_25.8.rXXXX Copyright (c) 2009-2015 Percona LLC and/or its affiliates Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or 'h' for help. Type 'c' to clear the current input statement. mysql>

   1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

   $mysql -h 0.0.0.0 -P 32768 -uroot Welcome to the MySQL monitor.  Commands end with ; or g. Your MySQL connection id is 10 Server version: 5.6.21-70.1 MySQL Community Server (GPL), wsrep_25.8.rXXXX   Copyright (c) 2009-2015 Percona LLC and/or its affiliates Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.   Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners.   Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.   mysql>

6. To change MySQL options either pass it as a mount at runtime with something like volume: /tmp/my.cnf:/etc/my.cnf in docker-compose.yml or connect to container’s bash (docker exec -i -t container_name /bin/bash), then change my.cnf and run docker restart container_name

Notes.

• If you don’t want to build use ready-to-use images
• If you don’t want to run Docker Compose as root user add yourself to docker group

Sveta Smirnova

Sveta joined Percona in 2015. Her main professional interests are problem solving, working with tricky issues, bugs, finding patterns that can solve typical issues quicker and teaching others how to deal with MySQL issues, bugs and gotchas effectively. Before joining Percona Sveta worked as a Support Engineer in the MySQL Bugs Analysis Support Group in MySQL AB-Sun-Oracle. She is the author of the book "MySQL Troubleshooting" and JSON UDF functions for MySQL.