New to KubeDB? Please start here.

Vertical Scale MongoDB Standalone

This guide will show you how to use KubeDB Enterprise operator to update the resources of a MongoDB standalone database.

Before You Begin

  • At first, you need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. If you do not already have a cluster, you can create one by using kind.

  • Install KubeDB Community and Enterprise operator in your cluster following the steps here.

  • You should be familiar with the following KubeDB concepts:

To keep everything isolated, we are going to use a separate namespace called demo throughout this tutorial.

$ kubectl create ns demo
namespace/demo created

Note: YAML files used in this tutorial are stored in docs/examples/mongodb directory of kubedb/docs repository.

Apply Vertical Scaling on Standalone

Here, we are going to deploy a MongoDB standalone using a supported version by KubeDB operator. Then we are going to apply vertical scaling on it.

Prepare MongoDB Standalone Database

Now, we are going to deploy a MongoDB standalone database with version 4.2.3.

Deploy MongoDB standalone

In this section, we are going to deploy a MongoDB standalone database. Then, in the next section we will update the resources of the database using MongoDBOpsRequest CRD. Below is the YAML of the MongoDB CR that we are going to create,

apiVersion: kubedb.com/v1alpha2
kind: MongoDB
metadata:
  name: mg-standalone
  namespace: demo
spec:
  version: "4.2.3"
  storageType: Durable
  storage:
    storageClassName: "standard"
    accessModes:
    - ReadWriteOnce
    resources:
      requests:
        storage: 1Gi

Let’s create the MongoDB CR we have shown above,

$ kubectl create -f https://github.com/kubedb/docs/raw/v2021.04.16/docs/examples/mongodb/scaling/mg-standalone.yaml
mongodb.kubedb.com/mg-standalone created

Now, wait until mg-standalone has status Ready. i.e,

$ kubectl get mg -n demo
NAME            VERSION    STATUS    AGE
mg-standalone   4.2.3      Ready     5m56s

Let’s check the Pod containers resources,

$ kubectl get pod -n demo mg-standalone-0 -o json | jq '.spec.containers[].resources'
{
  "limits": {
    "cpu": "500m",
    "memory": "1Gi"
  },
  "requests": {
    "cpu": "500m",
    "memory": "1Gi"
  }
}

You can see the Pod has default resources which is assigned by the Kubedb operator.

We are now ready to apply the MongoDBOpsRequest CR to update the resources of this database.

Vertical Scaling

Here, we are going to update the resources of the standalone database to meet the desired resources after scaling.

Create MongoDBOpsRequest

In order to update the resources of the database, we have to create a MongoDBOpsRequest CR with our desired resources. Below is the YAML of the MongoDBOpsRequest CR that we are going to create,

apiVersion: ops.kubedb.com/v1alpha1
kind: MongoDBOpsRequest
metadata:
  name: mops-vscale-standalone
  namespace: demo
spec:
  type: VerticalScaling
  databaseRef:
    name: mg-standalone
  verticalScaling:
    standalone:
      requests:
        memory: "2Gi"
        cpu: "1"
      limits:
        memory: "2Gi"
        cpu: "1"

Here,

  • spec.databaseRef.name specifies that we are performing vertical scaling operation on mops-vscale-standalone database.
  • spec.type specifies that we are performing VerticalScaling on our database.
  • spec.VerticalScaling.standalone specifies the desired resources after scaling.

Let’s create the MongoDBOpsRequest CR we have shown above,

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2021.04.16/docs/examples/mongodb/scaling/vertical-scaling/mops-vscale-standalone.yaml
mongodbopsrequest.ops.kubedb.com/mops-vscale-standalone created

Verify MongoDB Standalone resources updated successfully

If everything goes well, KubeDB Enterprise operator will update the resources of MongoDB object and related StatefulSets and Pods.

Let’s wait for MongoDBOpsRequest to be Successful. Run the following command to watch MongoDBOpsRequest CR,

$ kubectl get mongodbopsrequest -n demo
Every 2.0s: kubectl get mongodbopsrequest -n demo
NAME                     TYPE              STATUS       AGE
mops-vscale-standalone   VerticalScaling   Successful   108s

We can see from the above output that the MongoDBOpsRequest has succeeded. If we describe the MongoDBOpsRequest we will get an overview of the steps that were followed to scale the database.

$ kubectl describe mongodbopsrequest -n demo mops-vscale-standalone
Name:         mops-vscale-standalone
Namespace:    demo
Labels:       <none>
Annotations:  <none>
API Version:  ops.kubedb.com/v1alpha1
Kind:         MongoDBOpsRequest
Metadata:
  Creation Timestamp:  2021-03-02T17:19:38Z
  Generation:          1
  Managed Fields:
    API Version:  ops.kubedb.com/v1alpha1
    Fields Type:  FieldsV1
    fieldsV1:
      f:metadata:
        f:annotations:
          .:
          f:kubectl.kubernetes.io/last-applied-configuration:
      f:spec:
        .:
        f:databaseRef:
          .:
          f:name:
        f:type:
        f:verticalScaling:
          .:
          f:standalone:
            .:
            f:limits:
              .:
              f:cpu:
              f:memory:
            f:requests:
              .:
              f:cpu:
              f:memory:
    Manager:      kubectl-client-side-apply
    Operation:    Update
    Time:         2021-03-02T17:19:38Z
    API Version:  ops.kubedb.com/v1alpha1
    Fields Type:  FieldsV1
    fieldsV1:
      f:status:
        .:
        f:conditions:
        f:observedGeneration:
        f:phase:
    Manager:         kubedb-enterprise
    Operation:       Update
    Time:            2021-03-02T17:19:38Z
  Resource Version:  158587
  Self Link:         /apis/ops.kubedb.com/v1alpha1/namespaces/demo/mongodbopsrequests/mops-vscale-standalone
  UID:               364672b6-31b7-4fbe-878d-3de6c05161c9
Spec:
  Database Ref:
    Name:  mg-standalone
  Type:    VerticalScaling
  Vertical Scaling:
    Standalone:
      Limits:
        Cpu:     1
        Memory:  2Gi
      Requests:
        Cpu:     1
        Memory:  2Gi
Status:
  Conditions:
    Last Transition Time:  2021-03-02T17:19:38Z
    Message:               MongoDB ops request is vertically scaling database
    Observed Generation:   1
    Reason:                VerticalScaling
    Status:                True
    Type:                  VerticalScaling
    Last Transition Time:  2021-03-02T17:19:39Z
    Message:               Successfully updated StatefulSets Resources
    Observed Generation:   1
    Reason:                UpdateStatefulSetResources
    Status:                True
    Type:                  UpdateStatefulSetResources
    Last Transition Time:  2021-03-02T17:20:15Z
    Message:               Successfully Vertically Scaled Standalone Resources
    Observed Generation:   1
    Reason:                UpdateStandaloneResources
    Status:                True
    Type:                  UpdateStandaloneResources
    Last Transition Time:  2021-03-02T17:20:15Z
    Message:               Successfully Vertically Scaled Database
    Observed Generation:   1
    Reason:                Successful
    Status:                True
    Type:                  Successful
  Observed Generation:     1
  Phase:                   Successful
Events:
  Type    Reason                      Age   From                        Message
  ----    ------                      ----  ----                        -------
  Normal  PauseDatabase               43s   KubeDB Enterprise Operator  Pausing MongoDB demo/mg-standalone
  Normal  PauseDatabase               42s   KubeDB Enterprise Operator  Successfully paused MongoDB demo/mg-standalone
  Normal  Starting                    42s   KubeDB Enterprise Operator  Updating Resources of StatefulSet: mg-standalone
  Normal  UpdateStatefulSetResources  42s   KubeDB Enterprise Operator  Successfully updated StatefulSets Resources
  Normal  UpdateStandaloneResources   6s    KubeDB Enterprise Operator  Successfully Vertically Scaled Standalone Resources
  Normal  ResumeDatabase              6s    KubeDB Enterprise Operator  Resuming MongoDB demo/mg-standalone
  Normal  ResumeDatabase              6s    KubeDB Enterprise Operator  Successfully resumed MongoDB demo/mg-standalone
  Normal  Successful                  6s    KubeDB Enterprise Operator  Successfully Vertically Scaled Database

Now, we are going to verify from the Pod yaml whether the resources of the standalone database has updated to meet up the desired state, Let’s check,

$ kubectl get pod -n demo mg-standalone-0 -o json | jq '.spec.containers[].resources'
{
  "limits": {
    "cpu": "1",
    "memory": "2Gi"
  },
  "requests": {
    "cpu": "1",
    "memory": "2Gi"
  }
}

The above output verifies that we have successfully scaled up the resources of the MongoDB standalone database.

Cleaning Up

To clean up the Kubernetes resources created by this tutorial, run:

kubectl delete mg -n demo mg-standalone
kubectl delete mongodbopsrequest -n demo mops-vscale-standalone