Configuring automatic node provisioning in SQL Galera Cluster

26 Sep 2023

In a SQL Galera Cluster, automatic node provisioning allows for the automatic addition of new nodes to the cluster without manual intervention. This feature comes in handy when scaling the database cluster or replacing a failed node. In this blog post, we will explore how to configure automatic node provisioning in SQL Galera Cluster.

Prerequisites

Before we begin, ensure that you have the following prerequisites:

A SQL Galera Cluster up and running
Knowledge of the Galera Cluster configuration file - my.cnf

Step 1: Enabling SST Method and Cluster Name

To enable automatic node provisioning, you need to configure the cluster name and set the desired state snapshot transfer (SST) method in the Galera Cluster configuration file. Open the my.cnf file in your preferred text editor and make the following changes:

[mysqld]
wsrep_sst_method = rsync
wsrep_cluster_name = my_cluster

In the above configuration snippet, we set wsrep_sst_method to rsync as the SST method. Replace it with your preferred SST method if desired, such as xtrabackup-v2 or mysqldump.

Step 2: Configuring the Seeding Process

The seeding process involves configuring an initial node to bootstrap new nodes in the cluster. This process is helpful during node addition and recovery. Edit the configuration file as follows:

[mysqld]
wsrep_sst_seed = node1_ip_address, node2_ip_address, node3_ip_address

Replace node1_ip_address, node2_ip_address, etc., with the IP addresses of the existing nodes in your cluster. Ensure that you provide at least one reachable and active node for successful seeding.

Step 3: Restarting the Database Service

After making the necessary changes in the configuration file, restart the database service to apply the new settings:

sudo systemctl restart mysql

Step 4: Verifying the Configuration

To verify if automatic node provisioning is working correctly, check the Galera Cluster status using the SHOW STATUS command:

SHOW STATUS LIKE 'wsrep%';

Look for the wsrep_cluster_size variable - it should display the number of nodes in your cluster. If the value increases automatically upon adding a new node, then automatic node provisioning is successfully configured.

Conclusion

Configuring automatic node provisioning in SQL Galera Cluster simplifies the process of scaling the cluster and replacing failed nodes. By following the steps outlined in this blog post, you can enable automatic node provisioning and ensure easy management of your database cluster.

#GaleraCluster #NodeProvisioning