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ProxySQL Horizontal Scaling

This guide will give an overview on how KubeDB Ops Manager scales up or down ProxySQL Cluster.

Before You Begin

You should be familiar with the following KubeDB concepts:
- ProxySQL
- ProxySQLOpsRequest

The following diagram shows how KubeDB Ops Manager scales up or down ProxySQL components. Open the image in a new tab to see the enlarged version.

The Horizontal scaling process consists of the following steps:

At first, a user creates a ProxySQL Custom Resource (CR).
KubeDB Community operator watches the ProxySQL CR.
When the operator finds a ProxySQL CR, it creates required number of StatefulSets and related necessary stuff like secrets, services, etc.
Then, in order to scale the ProxySQL the user creates a ProxySQLOpsRequest CR with desired information.
KubeDB Enterprise operator watches the ProxySQLOpsRequest CR.
When it finds a ProxySQLOpsRequest CR, it pauses the ProxySQL object which is referred from the ProxySQLOpsRequest. So, the KubeDB Community operator doesn’t perform any operations on the ProxySQL object during the horizontal scaling process.
Then the KubeDB Enterprise operator will scale the related StatefulSet Pods to reach the expected number of replicas defined in the ProxySQLOpsRequest CR.
After the successfully scaling the replicas of the StatefulSet Pods, the KubeDB Enterprise operator updates the number of replicas in the ProxySQL object to reflect the updated state.
After the successful scaling of the ProxySQL replicas, the KubeDB Enterprise operator resumes the ProxySQL object so that the KubeDB Community operator resumes its usual operations.

In the next docs, we are going to show a step by step guide on horizontal scaling of ProxySQL database using ProxySQLOpsRequest CRD.