In a SQL Galera Cluster, a rolling upgrade is a procedure to update the nodes in the cluster to a new version while keeping the cluster operational. This ensures that there is no downtime during the upgrade process. In this blog post, we will discuss the steps to perform a rolling upgrade in SQL Galera Cluster.
Prerequisites
Before proceeding with the rolling upgrade, make sure you have taken the following precautions:
- Backup your Data: Take a full backup of your data to ensure data safety in case of any unforeseen issues during the upgrade.
- Test Environment: Set up a test environment to simulate the rolling upgrade process before implementing it in a production environment.
Step 1: Plan the Upgrade
Before starting the upgrade process, plan the sequence in which you want to upgrade the nodes in your SQL Galera Cluster. It is recommended to start with upgrading one node at a time to minimize the impact on the cluster’s availability.
Step 2: Disconnect the Node
To initiate the rolling upgrade, disconnect one node from the cluster. This can be done by stopping the Galera service or putting the node into maintenance mode. Ensure that the disconnected node is no longer participating in the cluster.
Step 3: Perform the Upgrade
With the disconnected node, perform the upgrade process according to the specific instructions provided by your SQL Galera Cluster provider. This usually involves updating the software, applying patches, or making necessary configuration changes.
Step 4: Reconnect the Node
Once the upgrade is completed on the disconnected node, reconnect it back to the cluster. Ensure that the node synchronizes with the other nodes in the cluster and rejoins the replication process.
Step 5: Verify Functionality
After the node is successfully reconnected to the cluster, it is important to verify its functionality. Perform necessary tests and checks to ensure that the upgraded node is functioning correctly and is properly synced with the other nodes.
Step 6: Repeat Steps 2-5 for Remaining Nodes
Repeat steps 2 to 5 for each remaining node in the SQL Galera Cluster. Disconnect, upgrade, reconnect, and verify the functionality of each node one by one.
Conclusion
Performing rolling upgrades in a SQL Galera Cluster allows you to update the cluster to a new version while keeping it operational. By following the steps outlined in this blog post, you can minimize downtime and ensure a smooth upgrade process for your SQL Galera Cluster.
#sqlgalera #rollingupgrades