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Druid Vertical Autoscaling

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

Before You Begin

• You should be familiar with the following KubeDB concepts:
  • Druid
  • DruidAutoscaler
  • DruidOpsRequest

How Storage Autoscaling Works

The following diagram shows how KubeDB Autoscaler operator autoscales the resources of Druid cluster 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 Druid Custom Resource (CR).

2. KubeDB Provisioner operator watches the Druid CR.

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

4. Each PetSet creates a Persistent Volume according to the Volume Claim Template provided in the petset configuration.

5. Then, in order to set up storage autoscaling of the druid data nodes (i.e. Historicals, MiddleManagers) of the Druid cluster, the user creates a DruidAutoscaler CRO with desired configuration.

6. KubeDB Autoscaler operator watches the DruidAutoscaler CRO.

7. KubeDB Autoscaler operator continuously watches persistent volumes of the clusters to check if it exceeds the specified usage threshold. If the usage exceeds the specified usage threshold, then KubeDB Autoscaler operator creates a DruidOpsRequest to expand the storage of the database.

8. KubeDB Ops-manager operator watches the DruidOpsRequest CRO.

9. Then the KubeDB Ops-manager operator will expand the storage of the cluster component as specified on the DruidOpsRequest CRO.

In the next docs, we are going to show a step-by-step guide on Autoscaling storage of various Druid cluster components using DruidAutoscaler CRD.