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Upgrade version of MongoDB Sharded Database

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

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

Deploy MongoDB Sharded Database

In this section, we are going to deploy a MongoDB sharded 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-sharding
  namespace: demo
spec:
  version: 3.6.8-v1
  shardTopology:
    configServer:
      replicas: 2
      storage:
        resources:
          requests:
            storage: 1Gi
        storageClassName: standard
    mongos:
      replicas: 2
    shard:
      replicas: 2
      shards: 3
      storage:
        resources:
          requests:
            storage: 1Gi
        storageClassName: standard

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

$ kubectl create -f https://github.com/kubedb/docs/raw/v2022.12.24-rc.1/docs/examples/mongodb/upgrading/mg-shard.yaml
mongodb.kubedb.com/mg-sharding created

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

$ k get mongodb -n demo                                                                                                                                             
NAME          VERSION    STATUS    AGE
mg-sharding   3.6.8-v1   Ready     2m9s

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

Upgrade MongoDB Version

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

Create MongoDBOpsRequest

In order to upgrade the sharded 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-shard-upgrade
  namespace: demo
spec:
  type: UpdateVersion
  databaseRef:
    name: mg-sharding
  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-sharding 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/v2022.12.24-rc.1/docs/examples/mongodb/upgrading/mops-upgrade-shard.yaml
mongodbopsrequest.ops.kubedb.com/mops-shard-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-shard-upgrade   UpdateVersion   Successful   2m31s

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-shard-upgrade

Name:         mops-shard-upgrade
Namespace:    demo
Labels:       <none>
Annotations:  <none>
API Version:  ops.kubedb.com/v1alpha1
Kind:         MongoDBOpsRequest
Metadata:
  Creation Timestamp:  2022-10-26T10:27:24Z
  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:         2022-10-26T10:27:24Z
    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:            2022-10-26T10:36:12Z
  Resource Version:  610193
  UID:               6459a314-c759-4002-9dff-106b836c4db0
Spec:
  Apply:  IfReady
  Database Ref:
    Name:  mg-sharding
  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:  2022-10-26T10:36:12Z
    Message:               connection() error occurred during connection handshake: dial tcp 10.244.0.125:27017: i/o timeout
    Observed Generation:   1
    Reason:                Failed
    Status:                False
    Type:                  UpgradeVersion
    Last Transition Time:  2022-10-26T10:29:29Z
    Message:               Successfully stopped mongodb load balancer
    Observed Generation:   1
    Reason:                StoppingBalancer
    Status:                True
    Type:                  StoppingBalancer
    Last Transition Time:  2022-10-26T10:30:54Z
    Message:               Successfully updated statefulsets update strategy type
    Observed Generation:   1
    Reason:                UpdateStatefulSets
    Status:                True
    Type:                  UpdateStatefulSets
    Last Transition Time:  2022-10-26T10:32:00Z
    Message:               Successfully Updated ConfigServer Image
    Observed Generation:   1
    Reason:                UpdateConfigServerImage
    Status:                True
    Type:                  UpdateConfigServerImage
    Last Transition Time:  2022-10-26T10:35:32Z
    Message:               Successfully Updated Shard Image
    Observed Generation:   1
    Reason:                UpdateShardImage
    Status:                True
    Type:                  UpdateShardImage
    Last Transition Time:  2022-10-26T10:36:07Z
    Message:               Successfully Updated Mongos Image
    Observed Generation:   1
    Reason:                UpdateMongosImage
    Status:                True
    Type:                  UpdateMongosImage
    Last Transition Time:  2022-10-26T10:36:07Z
    Message:               Successfully Started mongodb load balancer
    Observed Generation:   1
    Reason:                StartingBalancer
    Status:                True
    Type:                  StartingBalancer
    Last Transition Time:  2022-10-26T10:36:07Z
    Message:               Successfully completed the modification process.
    Observed Generation:   1
    Reason:                Successful
    Status:                True
    Type:                  Successful
  Observed Generation:     1
  Phase:                   Failed
Events:
  Type     Reason                   Age    From                         Message
  ----     ------                   ----   ----                         -------
  Normal   PauseDatabase            8m27s  KubeDB Ops-manager Operator  Pausing MongoDB demo/mg-sharding
  Normal   PauseDatabase            8m27s  KubeDB Ops-manager Operator  Successfully paused MongoDB demo/mg-sharding
  Normal   StoppingBalancer         8m27s  KubeDB Ops-manager Operator  Stopping Balancer
  Normal   StoppingBalancer         8m27s  KubeDB Ops-manager Operator  Successfully Stopped Balancer
  Normal   Updating                 8m27s  KubeDB Ops-manager Operator  Updating StatefulSets
  Normal   Updating                 7m2s   KubeDB Ops-manager Operator  Successfully Updated StatefulSets
  Normal   Updating                 7m2s   KubeDB Ops-manager Operator  Updating StatefulSets
  Normal   UpdateConfigServerImage  5m56s  KubeDB Ops-manager Operator  Successfully Updated ConfigServer Image
  Normal   Updating                 5m45s  KubeDB Ops-manager Operator  Successfully Updated StatefulSets
  Normal   UpdateShardImage         2m24s  KubeDB Ops-manager Operator  Successfully Updated Shard Image
  Normal   UpdateMongosImage        109s   KubeDB Ops-manager Operator  Successfully Updated Mongos Image
  Normal   Updating                 109s   KubeDB Ops-manager Operator  Starting Balancer
  Normal   StartingBalancer         109s   KubeDB Ops-manager Operator  Successfully Started Balancer
  Normal   ResumeDatabase           109s   KubeDB Ops-manager Operator  Resuming MongoDB demo/mg-sharding
  Normal   ResumeDatabase           109s   KubeDB Ops-manager Operator  Successfully resumed MongoDB demo/mg-sharding
  Normal   Successful               109s   KubeDB Ops-manager Operator  Successfully Updated Database

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

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

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

$ kubectl get sts -n demo mg-sharding-shard0 -o=jsonpath='{.spec.template.spec.containers[0].image}{"\n"}'
mongo:4.0.5

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

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

$ kubectl get pods -n demo mg-sharding-shard0-0 -o=jsonpath='{.spec.containers[0].image}{"\n"}'
mongo:4.0.5

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

You can see from above, our MongoDB sharded 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-sharding
kubectl delete mongodbopsrequest -n demo mops-shard-upgrade