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Upgrade version of MongoDB ReplicaSet
This guide will show you how to use KubeDB Ops-manager operator to upgrade the version of MongoDB ReplicaSet.
Before You Begin
At first, you need to have a Kubernetes cluster, and the
kubectlcommand-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
KubeDBProvisioner and Ops-manager operator in your cluster following the steps here.You should be familiar with the following
KubeDBconcepts:
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 ReplicaSet Database
Now, we are going to deploy a MongoDB replicaset database with version 3.6.8.
Deploy MongoDB replicaset
In this section, we are going to deploy a MongoDB replicaset 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-replicaset
namespace: demo
spec:
version: "3.6.8-v1"
replicaSet:
name: "replicaset"
replicas: 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/v2023.01.17/docs/examples/mongodb/upgrading/mg-replicaset.yaml
mongodb.kubedb.com/mg-replicaset created
Now, wait until mg-replicaset created has status Ready. i.e,
$ k get mongodb -n demo
NAME VERSION STATUS AGE
mg-replicaset 3.6.8-v1 Ready 109s
We are now ready to apply the MongoDBOpsRequest CR to upgrade this database.
Upgrade MongoDB Version
Here, we are going to upgrade MongoDB replicaset from 3.6.8 to 4.0.5.
Create MongoDBOpsRequest:
In order to upgrade the replicaset 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-replicaset-upgrade
namespace: demo
spec:
type: UpdateVersion
databaseRef:
name: mg-replicaset
upgrade:
targetVersion: 4.0.5-v3
readinessCriteria:
oplogMaxLagSeconds: 20
objectsCountDiffPercentage: 10
timeout: 5m
apply: IfReady
Here,
spec.databaseRef.namespecifies that we are performing operation onmg-replicasetMongoDB database.spec.typespecifies that we are going to performUpgradeon our database.spec.upgrade.targetVersionspecifies the expected version of the database4.0.5.- Have a look here on the respective sections to understand the
readinessCriteria,timeout&applyfields.
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-replicaset .yaml
mongodbopsrequest.ops.kubedb.com/mops-replicaset-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-replicaset-upgrade UpdateVersion Successful 84s
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-replicaset-upgrade
Name: mops-replicaset-upgrade
Namespace: demo
Labels: <none>
Annotations: <none>
API Version: ops.kubedb.com/v1alpha1
Kind: MongoDBOpsRequest
Metadata:
Creation Timestamp: 2022-10-26T10:19:55Z
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: 2022-10-26T10:19:55Z
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: 2022-10-26T10:23:09Z
Resource Version: 607814
UID: 38053605-47bd-4d94-9f53-ce9474ad0a98
Spec:
Apply: IfReady
Database Ref:
Name: mg-replicaset
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: 2022-10-26T10:21:20Z
Message: MongoDB ops request is upgrading database version
Observed Generation: 1
Reason: UpgradeVersion
Status: True
Type: UpgradeVersion
Last Transition Time: 2022-10-26T10:21:39Z
Message: Successfully updated statefulsets update strategy type
Observed Generation: 1
Reason: UpdateStatefulSets
Status: True
Type: UpdateStatefulSets
Last Transition Time: 2022-10-26T10:23:09Z
Message: Successfully Updated Standalone Image
Observed Generation: 1
Reason: UpdateStandaloneImage
Status: True
Type: UpdateStandaloneImage
Last Transition Time: 2022-10-26T10:23:09Z
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 2m27s KubeDB Ops-manager Operator Pausing MongoDB demo/mg-replicaset
Normal PauseDatabase 2m27s KubeDB Ops-manager Operator Successfully paused MongoDB demo/mg-replicaset
Normal Updating 2m27s KubeDB Ops-manager Operator Updating StatefulSets
Normal Updating 2m8s KubeDB Ops-manager Operator Successfully Updated StatefulSets
Normal UpdateStandaloneImage 38s KubeDB Ops-manager Operator Successfully Updated Standalone Image
Normal ResumeDatabase 38s KubeDB Ops-manager Operator Resuming MongoDB demo/mg-replicaset
Normal ResumeDatabase 38s KubeDB Ops-manager Operator Successfully resumed MongoDB demo/mg-replicaset
Normal Successful 38s KubeDB Ops-manager Operator Successfully Updated Database
Now, we are going to verify whether the MongoDB and the related StatefulSets and their Pods have the new version image. Let’s check,
$ kubectl get mg -n demo mg-replicaset -o=jsonpath='{.spec.version}{"\n"}'
4.0.5-v3
$ kubectl get sts -n demo mg-replicaset -o=jsonpath='{.spec.template.spec.containers[0].image}{"\n"}'
mongo:4.0.5
$ kubectl get pods -n demo mg-replicaset-0 -o=jsonpath='{.spec.containers[0].image}{"\n"}'
mongo:4.0.5
You can see from above, our MongoDB replicaset 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-replicaset
kubectl delete mongodbopsrequest -n demo mops-replicaset-upgrade