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Kafka Vertical Autoscaling

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

Before You Begin

• You should be familiar with the following KubeDB concepts:
  • Kafka
  • KafkaAutoscaler
  • KafkaOpsRequest

How Storage Autoscaling Works

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

2. KubeDB Provisioner operator watches the Kafka CR.

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

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

4. Then, in order to set up storage autoscaling of the various components (ie. Combined, Broker, Controller.) of the Kafka cluster, the user creates a KafkaAutoscaler CRO with desired configuration.

5. KubeDB Autoscaler operator watches the KafkaAutoscaler CRO.

6. 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 KafkaOpsRequest to expand the storage of the database.

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

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

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