Restart This Running MariaDB Galera Cluster

15 minutes
  • 4 Learning Objectives

About this Hands-on Lab

In this activity you are working as a DBA and have been tasked with stopping and restarting a running MariaDB Galera Cluster, to allow for data center maintenance.

Learning Objectives

Successfully complete this lab by achieving the following learning objectives:

Stop All Nodes

The MariaDB server needs to be stopped on all nodes:

sudo systemctl stop mariadb.service
Determine Most Advanced Node

The grastate.dat file needs to be examined on each node, to determine which is most advanced:

sudo cat /var/lib/mysql/grastate.dat
Bootstrap the Most Advanced Node

The following commands will be run only on the most advanced, node as determined in the previous step.

Edit node configuration in /etc/my.cnf.d/:

wsrep_cluster_address=gcomm://

Start the node:

sudo systemctl stop mariadb.service
Check Status and Add Nodes to the Cluster

Now we can connect to the server using using the mysql client on the node we bootstrapped in the previous step:

mysql

Once connected, we can run the following SQL statement to confirm the cluster is running:

SHOW GLOBAL STATUS WHERE Variable_name IN ('wsrep_ready', 'wsrep_cluster_size', 'wsrep_cluster_status', 'wsrep_connected');

A cluster size of 1 means only one node is connected.

To join the other node to the cluster, we need to edit its configuration in /etc/my.cnf.d/. Be certain to use the private IP of the already running node for the cluster address:

wsrep_cluster_address=gcom://10.0.1.110

Start the node:

sudo systemctl start mariadb.service

Additional Resources

In this activity you are working as a DBA and have been tasked with stopping and restarting a running MariaDB Galera Cluster, to allow for data center maintenance.

To do this you will need to complete the following steps:

  1. Stop MariaDB service on all nodes.
  2. Determine the most advanced node.
  3. Bootstrap the most advanced node.
  4. Check status and add nodes to the cluster.

What are Hands-on Labs

Hands-on Labs are real environments created by industry experts to help you learn. These environments help you gain knowledge and experience, practice without compromising your system, test without risk, destroy without fear, and let you learn from your mistakes. Hands-on Labs: practice your skills before delivering in the real world.

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