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MongoDB Vertical Autoscaling

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

Before You Begin

How Storage Autoscaling Works

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

  Storage Autoscaling process of MongoDB
Fig: Storage Autoscaling process of MongoDB

The Auto Scaling process consists of the following steps:

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

  2. KubeDB Community operator watches the MongoDB CR.

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

  4. Each StatefulSet creates a Persistent Volume according to the Volume Claim Template provided in the statefulset configuration. This Persistent Volume will be expanded by the KubeDB Enterprise operator.

  5. Then, in order to set up storage autoscaling of the various components (ie. ReplicaSet, Shard, ConfigServer etc.) of the MongoDB database the user creates a MongoDBAutoscaler CRO with desired configuration.

  6. KubeDB Autoscaler operator watches the MongoDBAutoscaler CRO.

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

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

  9. KubeDB Enterprise operator watches the MongoDBOpsRequest CRO.

  10. Then the KubeDB Enterprise operator will expand the storage of the database component as specified on the MongoDBOpsRequest CRO.

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