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Users

MongoDB user accounts within the Cluster can be divided into two different groups:

  • application-level users: the unprivileged user accounts,
  • system-level users: the accounts needed to automate the cluster deployment and management tasks, such as MongoDB Health checks.

As these two groups of user accounts serve different purposes, they are considered separately in the following sections.

Unprivileged users

There are no unprivileged (general purpose) user accounts created by default. If you need general purpose users, please run commands below:

$ kubectl run -i --rm --tty percona-client --image=percona/percona-server-mongodb:4.4.24-23 --restart=Never -- bash -il
mongodb@percona-client:/$ mongo "mongodb+srv://userAdmin:userAdmin123456@my-cluster-name-rs0.psmdb.svc.cluster.local/admin?replicaSet=rs0&ssl=false"
rs0:PRIMARY> db.createUser({
    user: "myApp",
    pwd: "myAppPassword",
    roles: [
      { db: "myApp", role: "readWrite" }
    ],
    mechanisms: [
       "SCRAM-SHA-1"
    ]

})

Now check the newly created user:

$ kubectl run -i --rm --tty percona-client --image=percona/percona-server-mongodb:4.4.24-23 --restart=Never -- bash -il
mongodb@percona-client:/$ mongo "mongodb+srv://myApp:myAppPassword@my-cluster-name-rs0.psmdb.svc.cluster.local/admin?replicaSet=rs0&ssl=false"
rs0:PRIMARY> use myApp
rs0:PRIMARY> db.test.insert({ x: 1 })
rs0:PRIMARY> db.test.findOne()

System Users

To automate the deployment and management of the cluster components, the Operator requires system-level MongoDB users.

Credentials for these users are stored as a Kubernetes Secrets object. The Operator requires Kubernetes Secret before the database cluster is started. It will either use existing Secret or create a new Secret with randomly generated passwords if it didn’t exist. The name of the required Secret should be set in the spec.secrets.users option of the deploy/cr.yaml configuration file.

Default Secret name: my-cluster-name-secrets

Secret name field: spec.secrets.users

Warning

These users should not be used to run an application.

User Purpose Username Secret Key Password Secret Key
Backup/Restore MONGODB_BACKUP_USER MONGODB_BACKUP_PASSWORD
Cluster Admin MONGODB_CLUSTER_ADMIN_USER MONGODB_CLUSTER_ADMIN_PASSWORD
Cluster Monitor MONGODB_CLUSTER_MONITOR_USER MONGODB_CLUSTER_MONITOR_PASSWORD
Database Admin MONGODB_DATABASE_ADMIN_USER MONGODB_DATABASE_ADMIN_PASSWORD
User Admin MONGODB_USER_ADMIN_USER MONGODB_USER_ADMIN_PASSWORD
PMM Server PMM_SERVER_USER PMM_SERVER_PASSWORD

Password-based authorization method for PMM is deprecated since the Operator 1.13.0. Use token-based authorization instead.

If you change credentials for the MONGODB_CLUSTER_MONITOR user, the cluster Pods will go into restart cycle, and the cluster can be not accessible through the mongos service until this cycle finishes.

Note

In some situations it can be needed to reproduce system users in a bare-bone MongoDB. For example, that’s a required step in the migration scenarios to move existing on-prem MongoDB database to Kubernetes-based MongoDB cluster managed by the Operator. You can use the following example script which produces a text file with mongo shell commands to create needed system users with appropriate roles:

gen_users.sh 
clusterAdminPass="clusterAdmin"
userAdminPass="userAdmin"
clusterMonitorPass="clusterMonitor"
backupPass="backup"

# mongo shell
cat <<EOF > user-mongo-shell.txt
use admin
db.createRole(
{
"roles": [],
role: "pbmAnyAction",
"privileges" : [
                {
                        "resource" : {
                                "anyResource" : true
                        },
                        "actions" : [
                                "anyAction"
                        ]
                }
        ],

})

db.createUser( { user: "clusterMonitor", pwd: "$clusterMonitorPass", roles: [ "clusterMonitor" ] } )
db.createUser( { user: "userAdmin", pwd: "$userAdminPass", roles: [ "userAdminAnyDatabase" ] } )
db.createUser( { user: "clusterAdmin", pwd: "$clusterAdminPass", roles: [ "clusterAdmin" ] } )
db.createUser( { user: "backup", pwd: "$backupPass", roles: [ "readWrite", "backup", "clusterMonitor", "restore", "pbmAnyAction" ] } )
EOF

YAML Object Format

The default name of the Secrets object for these users is my-cluster-name-secrets and can be set in the CR for your cluster in spec.secrets.users to something different. When you create the object yourself, the corresponding YAML file should match the following simple format:

apiVersion: v1
kind: Secret
metadata:
  name: my-cluster-name-secrets
type: Opaque
stringData:
  MONGODB_BACKUP_USER: backup
  MONGODB_BACKUP_PASSWORD: backup123456
  MONGODB_DATABASE_ADMIN_USER: databaseAdmin
  MONGODB_DATABASE_ADMIN_PASSWORD: databaseAdmin123456
  MONGODB_CLUSTER_ADMIN_USER: clusterAdmin
  MONGODB_CLUSTER_ADMIN_PASSWORD: clusterAdmin123456
  MONGODB_CLUSTER_MONITOR_USER: clusterMonitor
  MONGODB_CLUSTER_MONITOR_PASSWORD: clusterMonitor123456
  MONGODB_USER_ADMIN_USER: userAdmin
  MONGODB_USER_ADMIN_PASSWORD: userAdmin123456
  PMM_SERVER_USER: admin
  PMM_SERVER_PASSWORD: admin
  PMM_SERVER_API_KEY: apikey

The example above matches what is shipped in deploy/secrets.yaml which contains default passwords and default API key. You should NOT use these in production, but they are present to assist in automated testing or simple use in a development environment.

As you can see, because we use the stringData type when creating the Secrets object, all values for each key/value pair are stated in plain text format convenient from the user’s point of view. But the resulting Secrets object contains passwords stored as data - i.e., base64-encoded strings. If you want to update any field, you’ll need to encode the value into base64 format. To do this, you can run echo -n "password" | base64 --wrap=0 (or just echo -n "password" | base64 in case of Apple macOS) in your local shell to get valid values. For example, setting the Database Admin user’s password to new_password in the my-cluster-name-secrets object can be done with the following command:

$ kubectl patch secret/my-cluster-name-secrets -p '{"data":{"MONGODB_DATABASE_ADMIN_PASSWORD": "'$(echo -n new_password | base64 --wrap=0)'"}}'

$ kubectl patch secret/my-cluster-name-secrets -p '{"data":{"MONGODB_DATABASE_ADMIN_PASSWORD": "'$(echo -n new_password | base64)'"}}'

Note

The operator creates and updates an additional Secrets object named based on the cluster name, like internal-my-cluster-name-users. It is used only by the Operator and should undergo no manual changes by the user. This object contains secrets with the same passwords as the one specified in spec.secrets.users (e.g. my-cluster-name-secrets). When the user updates my-cluster-name-secrets, the Operator propagates these changes to the internal internal-my-cluster-name-users Secrets object.

Password Rotation Policies and Timing

When there is a change in user secrets, the Operator creates the necessary transaction to change passwords. This rotation happens almost instantly (the delay can be up to a few seconds), and it’s not needed to take any action beyond changing the password.

Note

Please don’t change secrets.users option in CR, make changes inside the secrets object itself.

Development Mode

To make development and testing easier, deploy/secrets.yaml secrets file contains default passwords for MongoDB system users.

These development-mode credentials from deploy/secrets.yaml are:

Secret Key Secret Value
MONGODB_BACKUP_USER backup
MONGODB_BACKUP_PASSWORD backup123456
MONGODB_DATABASE_ADMIN_USER databaseAdmin
MONGODB_DATABASE_ADMIN_PASSWORD databaseAdmin123456
MONGODB_CLUSTER_ADMIN_USER clusterAdmin
MONGODB_CLUSTER_ADMIN_PASSWORD clusterAdmin123456
MONGODB_CLUSTER_MONITOR_USER clusterMonitor
MONGODB_CLUSTER_MONITOR_PASSWORD clusterMonitor123456
MONGODB_USER_ADMIN_USER userAdmin
MONGODB_USER_ADMIN_PASSWORD userAdmin123456
PMM_SERVER_USER admin
PMM_SERVER_PASSWORD admin
PMM_SERVER_API_KEY apikey

Warning

Do not use the default MongoDB Users and/or default PMM API key in production!

MongoDB Internal Authentication Key (optional)

Default Secret name: my-cluster-name-mongodb-key

Secret name field: spec.secrets.key

By default, the operator will create a random, 1024-byte key for MongoDB Internal Authentication if it does not already exist. If you would like to deploy a different key, create the secret manually before starting the operator.

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Last update: 2024-04-22