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Upgrade version of MongoDB Standalone

This guide will show you how to use KubeDB Ops-manager operator to upgrade the version of MongoDB standalone.

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 Provisioner and Ops-manager 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.

Prepare MongoDB Standalone Database

Now, we are going to deploy a MongoDB standalone database with version 3.6.8.

Deploy MongoDB standalone :

In this section, we are going to deploy a MongoDB standalone database. Then, in the next section we will upgrade the version 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: "3.6.8-v1"
  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/v2023.01.17/docs/examples/mongodb/upgrading/mg-standalone.yaml
mongodb.kubedb.com/mg-standalone created

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

$ kubectl get mg -n demo
  NAME            VERSION    STATUS    AGE
  mg-standalone   3.6.8-v1   Ready     8m58s

We are now ready to apply the MongoDBOpsRequest CR to upgrade this database.

Upgrade MongoDB Version

Here, we are going to upgrade MongoDB standalone from 3.6.8 to 4.0.5.

Create MongoDBOpsRequest:

In order to upgrade the standalone database, we have to create a MongoDBOpsRequest CR with your desired version that is supported by KubeDB. Below is the YAML of the MongoDBOpsRequest CR that we are going to create,

apiVersion: ops.kubedb.com/v1alpha1
kind: MongoDBOpsRequest
metadata:
  name: mops-upgrade
  namespace: demo
spec:
  type: UpdateVersion
  databaseRef:
    name: mg-standalone
  upgrade:
    targetVersion: 4.0.5-v3
  readinessCriteria:
    oplogMaxLagSeconds: 20
    objectsCountDiffPercentage: 10
  timeout: 5m
  apply: IfReady

Here,

  • spec.databaseRef.name specifies that we are performing operation on mg-standalone MongoDB database.
  • spec.type specifies that we are going to perform Upgrade on our database.
  • spec.upgrade.targetVersion specifies the expected version of the database 4.0.5.
  • Have a look here on the respective sections to understand the readinessCriteria, timeout & apply fields.

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

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2023.01.17/docs/examples/mongodb/upgrading/mops-upgrade-standalone.yaml
mongodbopsrequest.ops.kubedb.com/mops-upgrade created

Verify MongoDB version upgraded successfully :

If everything goes well, KubeDB Ops-manager operator will update the image 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-upgrade   UpdateVersion   Successful   3m45s

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 upgrade the database.

$ kubectl describe mongodbopsrequest -n demo mops-upgrade
Name:         mops-upgrade
Namespace:    demo
Labels:       <none>
Annotations:  <none>
API Version:  ops.kubedb.com/v1alpha1
Kind:         MongoDBOpsRequest
Metadata:
  Creation Timestamp:  2022-10-26T10:06:50Z
  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:apply:
        f:databaseRef:
        f:readinessCriteria:
          .:
          f:objectsCountDiffPercentage:
          f:oplogMaxLagSeconds:
        f:timeout:
        f:type:
        f:upgrade:
          .:
          f:targetVersion:
    Manager:      kubectl-client-side-apply
    Operation:    Update
    Time:         2022-10-26T10:06:50Z
    API Version:  ops.kubedb.com/v1alpha1
    Fields Type:  FieldsV1
    fieldsV1:
      f:status:
        .:
        f:conditions:
        f:observedGeneration:
        f:phase:
    Manager:         kubedb-ops-manager
    Operation:       Update
    Subresource:     status
    Time:            2022-10-26T10:08:25Z
  Resource Version:  605817
  UID:               79faadf6-7af9-4b74-9907-febe7d543386
Spec:
  Apply:  IfReady
  Database Ref:
    Name:  mg-standalone
  Readiness Criteria:
    Objects Count Diff Percentage:  10
    Oplog Max Lag Seconds:          20
  Timeout:                          5m
  Type:                             UpdateVersion
  Upgrade:
    Target Version:  4.0.5-v3
Status:
  Conditions:
    Last Transition Time:  2022-10-26T10:07:10Z
    Message:               MongoDB ops request is upgrading database version
    Observed Generation:   1
    Reason:                UpgradeVersion
    Status:                True
    Type:                  UpgradeVersion
    Last Transition Time:  2022-10-26T10:07:30Z
    Message:               Successfully updated statefulsets update strategy type
    Observed Generation:   1
    Reason:                UpdateStatefulSets
    Status:                True
    Type:                  UpdateStatefulSets
    Last Transition Time:  2022-10-26T10:08:25Z
    Message:               Successfully Updated Standalone Image
    Observed Generation:   1
    Reason:                UpdateStandaloneImage
    Status:                True
    Type:                  UpdateStandaloneImage
    Last Transition Time:  2022-10-26T10:08:25Z
    Message:               Successfully completed the modification process.
    Observed Generation:   1
    Reason:                Successful
    Status:                True
    Type:                  Successful
  Observed Generation:     1
  Phase:                   Successful
Events:
  Type    Reason                 Age   From                         Message
  ----    ------                 ----  ----                         -------
  Normal  PauseDatabase          2m5s  KubeDB Ops-manager Operator  Pausing MongoDB demo/mg-standalone
  Normal  PauseDatabase          2m5s  KubeDB Ops-manager Operator  Successfully paused MongoDB demo/mg-standalone
  Normal  Updating               2m5s  KubeDB Ops-manager Operator  Updating StatefulSets
  Normal  Updating               105s  KubeDB Ops-manager Operator  Successfully Updated StatefulSets
  Normal  UpdateStandaloneImage  50s   KubeDB Ops-manager Operator  Successfully Updated Standalone Image
  Normal  ResumeDatabase         50s   KubeDB Ops-manager Operator  Resuming MongoDB demo/mg-standalone
  Normal  ResumeDatabase         50s   KubeDB Ops-manager Operator  Successfully resumed MongoDB demo/mg-standalone
  Normal  Successful             50s   KubeDB Ops-manager Operator  Successfully Updated Database

Now, we are going to verify whether the MongoDB and the related StatefulSets their Pods have the new version image. Let’s check,

$ kubectl get mg -n demo mg-standalone -o=jsonpath='{.spec.version}{"\n"}'                                                                                          
4.0.5-v3

$ kubectl get sts -n demo mg-standalone -o=jsonpath='{.spec.template.spec.containers[0].image}{"\n"}'                                                               
mongo:4.0.5

$ kubectl get pods -n demo mg-standalone-0 -o=jsonpath='{.spec.containers[0].image}{"\n"}'                                                                           
mongo:4.0.5

You can see from above, our MongoDB standalone database has been updated with the new version. So, the upgrade process is successfully completed.

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-upgrade