New to KubeDB? Please start here.

ClickHouse Update Version Overview

This guide will give you an overview on how KubeDB Ops-manager operator update the version of ClickHouse.

Before You Begin

• You should be familiar with the following KubeDB concepts:
  • ClickHouse
  • ClickHouseOpsRequest

How update version Process Works

The following diagram shows how KubeDB Ops-manager operator used to update the version of ClickHouse. Open the image in a new tab to see the enlarged version.

  

The updating process consists of the following steps:

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

2. KubeDB Provisioner operator watches the ClickHouse CR.

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

4. Then, in order to update the version of the ClickHouse database the user creates a ClickHouseOpsRequest CR with the desired version.

5. KubeDB Ops-manager operator watches the ClickHouseOpsRequest CR.

6. When it finds a ClickHouseOpsRequest CR, it halts the ClickHouse object which is referred from the ClickHouseOpsRequest. So, the KubeDB Provisioner operator doesn’t perform any operations on the ClickHouse object during the updating process.

7. By looking at the target version from ClickHouseOpsRequest CR, KubeDB Ops-manager operator updates the images of all the PetSets.

8. After successfully updating the PetSets and their Pods images, the KubeDB Ops-manager operator updates the image of the ClickHouse object to reflect the updated state of the database.

9. After successfully updating of ClickHouse object, the KubeDB Ops-manager operator resumes the ClickHouse object so that the KubeDB Provisioner operator can resume its usual operations.

In the next doc, we are going to show a step by step guide on updating of a ClickHouse database using updateVersion operation.