How upgrade MonogDB Community on AKS

Comment upgrade Mongodb Community sur son AKS

Here we’ll look at how to upgrade Mongodb Community from 4.4.10 to 7.0.0 . No matter how hard I searched, I couldn’t find anything to help me, so I might as well help those who will have to deal with it!

Mongodb Community

1. Let’s start with a simple deployment, with one user and one database :

apiVersion: mongodbcommunity.mongodb.com/v1
kind: MongoDBCommunity
metadata:
  name: my-mongo
  namespace: mongo
spec:
  additionalMongodConfig:
    storage.wiredTiger.engineConfig.journalCompressor: zlib
  members: 3
  security:
    authentication:
      ignoreUnknownUsers: true
      modes:
        - SCRAM
    tls:
      enabled: false
  statefulSet:
    spec:
      template:
        spec:
          containers:
            - name: mongod
              resources:
                limits:
                  cpu: '3'
                  memory: 4Gi
                requests:
                  cpu: '2'
                  memory: 2Gi
            - name: mongodb-agent
              resources:
                limits:
                  cpu: '0.5'
                  memory: 512M
                requests:
                  cpu: '0.2'
                  memory: 200M
  type: ReplicaSet
  users:
    - name: admin
      db: admin
      scramCredentialsSecretName: my-scram-admin
      passwordSecretRef:
        name: admin-password
      roles:
        - name: clusterAdmin
          db: admin
        - name: userAdminAnyDatabase
          db: admin
    - name: dev-db
      db: dev-db
      scramCredentialsSecretName: my-scram-dev
      passwordSecretRef:
        name: dev-db-password
      roles:
        - name: readWrite
          db: dev-db
  version: 4.4.10
  featureCompatibilityVersion: '4.4'

2. Here there are 2 scenarios: in the first, you have this featureCompatibilityVersion in your yaml and in this case bravo, if not you must add it as in the example above.

3. Access the primary pod, then connect to the database :

  mongo -u admin -p PASSWORD --authenticationDatabase admin

4. Once in the database, place these commands :

  # passer en admin
  use admin

  # Verifier le eatureCompatibilityVersion
  db.adminCommand({getParameter: 1,featureCompatibilityVersion: 1})

5. If all goes well, you should get a result that says :

     {
       "featureCompatibilityVersion" : {
               "version" : "4.4" # we're on the right version
       },
       "ok" : 1,
       "$clusterTime" : {
               "clusterTime" : Timestamp(1692709763, 3),
               "signature" : {
                       "hash" : BinData(0,"G2h/IOKY+TIMtryV9dDkEt2rlkw="),
                       "keyId" : NumberLong("7263035781982191620")
               }
       },
       "operationTime" : Timestamp(1692709763, 3)
     }

6. If you get the wrong result, just place this command and test again:

     db.adminCommand( { setFeatureCompatibilityVersion: "4.4" } )

7. Now that the featureCompatibilityVersion corresponds to the mongodb version, you can perform the upgrade. Just change the versions :

   version: 5.0.0
   featureCompatibilityVersion: '5.0'

IMPORTANT NOTE: to upgrade from version 4.4.10 to 7.0.0, for example, you must go through the intermediate major releases, i.e. 4.4.10->5.0.0->6.0.9->7.0.0.

8. Wait for all pods to redeploy, then repeat step 4 to check that the mongo version corresponds to the featureCompatibilityVersion version, otherwise repeat step 6.

IMPORTANT NOTE: for the featureCompatibilityVersion, here are the versions to use: 4.4, 5.0, 6.0 and 7.0.

Conclusion

Now you can upgrade your mongodb without any featureCompatibilityVersion problems.