MongoDB replica set with authentication fails to start

How do we setup authentication or define a root user?

So far I have tried:

1. Setting MONGO_INITDB_ROOT_USERNAME and MONGO_INITDB_ROOT_PASSWORD environment variables on mongo container. Mongo container fails to start with “Error: couldn’t add user: not master :” which is fair since we pass --replSet flag and it tries adding a user before rs.initiate();
2. Passing --auth flag to mongod and running post start script on container to add a root user:

sleep 5;
mongo --eval 'rs.initiate()';
mongo --eval 'db=db.getSiblingDB("admin");db.createUser({ user: "root", pwd: "root", roles: [{ role: "root", db: "admin" }]})';

The user is added successfully but sidecar fails with: The hosts mongo-0:27017 and 10.0.12.57:27017 all map to this node in new configuration version 2 for replica set rs0 as it tries to add the same replica again as mongo-0 is 10.0.12.57.

So what’s the proper way of enabling authentication?

[romanlytvyn]

I’ve come up with some kind of a workaround:

...
containers:
  - name: mongo
    image: mongo
    command:
    - /bin/sh
    - -c
    - >
      if [ -f /data/db/key ]; then
        mongod --keyFile /data/db/key --replSet rs0;
      else
        mongod --auth;
      fi;
    lifecycle:
      postStart:
        exec:
          command:
          - /bin/sh
          - -c
          - >
            if [ ! -f /data/db/key ]; then
              sleep 5;

              echo "SOMESTRONGPASSWORD" > /data/db/key
              chmod 600 /data/db/key

              if [ "$HOSTNAME" = "mongo-0" ]; then
                mongo --eval 'db = db.getSiblingDB("admin"); db.createUser({ user: "root", pwd: "root", roles: [{ role: "root", db: "admin" }]});';
              fi;

              mongod --shutdown;
            fi;
    ports:
      - containerPort: 27017
    volumeMounts:
      - name: mongo-persistent-storage
        mountPath: /data/db
  - name: mongo-sidecar
    image: cvallance/mongo-k8s-sidecar
    env:
      - name: MONGO_SIDECAR_POD_LABELS
        value: "role=mongo,environment=test"
      - name: MONGODB_DATABASE
        value: "admin"
      - name: MONGODB_USERNAME
        value: "root"
      - name: MONGODB_PASSWORD
        value: "root"
...

The idea is to start a container without --replSet (to be able to add a user without rs.initiate()), create a key file on container start and add a user on primary node (mongo-0) and restart container with --keyFile and --replSet.

Please let me know if there is a proper way of doing this.

[supereagle]

@nrobert13 Thanks. I have enabled authentication with similar way.