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Horizontal Scaling Overview
This guide will give you an overview of how KubeDB enterprise operator scales up/down the number of members of a MySQL
group replication.
Before You Begin
- You should be familiar with the following
KubeDB
concepts:
How Horizontal Scaling Process Works
The following diagram shows how KubeDB enterprise operator used to scale up the number of members of a MySQL
group replication. Open the image in a new tab to see the enlarged version.
![Stash Backup Flow](/docs/v2022.10.18/guides/mysql/scaling/horizontal-scaling/overview/images/my-horizontal_scaling.png)
The horizontal scaling process consists of the following steps:
At first, a user creates a
MySQL
cr.KubeDB
community operator watches for theMySQL
cr.When it finds one, it creates a
StatefulSet
and related necessary stuff like secret, service, etc.Then, in order to scale the cluster, the user creates a
MySQLOpsRequest
cr with the desired number of members after scaling.KubeDB
enterprise operator watches forMySQLOpsRequest
.When it finds one, it halts the
MySQL
object so that theKubeDB
community operator doesn’t perform any operation on theMySQL
during the scaling process.Then the
KubeDB
enterprise operator will scale the StatefulSet replicas to reach the expected number of members for the group replication.After successful scaling of the StatefulSet’s replica, the
KubeDB
enterprise operator updates thespec.replicas
field ofMySQL
object to reflect the updated cluster state.After successful scaling of the
MySQL
replicas, theKubeDB
enterprise operator resumes theMySQL
object so that theKubeDB
community operator can resume its usual operations.
In the next doc, we are going to show a step by step guide on scaling of a MySQL group replication using Horizontal Scaling.