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Cassandra Vertical Autoscaling

This guide will give an overview on how KubeDB Autoscaler operator autoscales the database storage using CassandraAutoscaler crd.

Before You Begin

• You should be familiar with the following KubeDB concepts:
  • Cassandra
  • CassandraAutoscaler
  • CassandraOpsRequest

How Storage Autoscaling Works

  

The following diagram shows how KubeDB Autoscaler operator autoscales the resources of Cassandra database components. Open the image in a new tab to see the enlarged version.

The Auto Scaling process consists of the following steps:

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

2. KubeDB Provisioner operator watches the Cassandra CR.

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

• Each StatefulSet creates a Persistent Volume according to the Volume Claim Template provided in the statefulset configuration.

4. Then, in order to set up storage autoscaling of the Cassandra cluster, the user creates a CassandraAutoscaler CRO with desired configuration.

5. KubeDB Autoscaler operator watches the CassandraAutoscaler CRO.

6. KubeDB Autoscaler operator continuously watches persistent volumes of the databases to check if it exceeds the specified usage threshold.

• If the usage exceeds the specified usage threshold, then KubeDB Autoscaler operator creates a CassandraOpsRequest to expand the storage of the database.

7. KubeDB Ops-manager operator watches the CassandraOpsRequest CRO.

8. Then the KubeDB Ops-manager operator will expand the storage of the database component as specified on the CassandraOpsRequest CRO.

In the next docs, we are going to show a step by step guide on Autoscaling storage of various Cassandra database components using CassandraAutoscaler CRD.