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Hazelcast Horizontal Scaling

This guide will give an overview on how KubeDB Ops Manager scales up or down of Hazelcast database cluster members.

Before You Begin

• You should be familiar with the following KubeDB concepts:
  • Hazelcast
  • HazelcastOpsRequest

How Horizontal Scaling Process Works

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

  

The scaling process consists of the following steps:

1. At first, a user creates a Hazelcast Custom Resource (CR).

2. KubeDB Community operator watches the Hazelcast CR.

3. When the operator finds a Hazelcast CR, it creates required number of StatefulSets and related necessary stuff like appbinding, services, etc.

4. Then, in order to scale the cluster, the user creates a HazelcastOpsRequest CR with desired information.

5. KubeDB Enterprise operator watches the HazelcastOpsRequest CR.

6. When it finds a HazelcastOpsRequest CR, it halts the Hazelcast object which is referred from the HazelcastOpsRequest. So, the KubeDB Community operator doesn’t perform any operations on the Hazelcast object during the scaling process.

7. Then the KubeDB Enterprise operator will scale the related PetSets to reach the expected number of members defined in the HazelcastOpsRequest CR.

8. After the successfully scaling the StatefulSets replicas, the KubeDB Enterprise operator updates the number of members in the Hazelcast object to reflect the updated state of the database.

9. After the successful scaling of Hazelcast members, the KubeDB Enterprise operator resumes the Hazelcast 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 Hazelcast database using HazelcastOpsRequest CRD.