Configure authentication in MongoDB

Percona Backup for MongoDB uses the authentication and authorization subsystem of MongoDB. This means that to authenticate Percona Backup for MongoDB, you need to:

• Create a corresponding pbm user in the admin database
• Set a valid MongoDB connection URI string for pbm-agent
• Set a valid MongoDB connection URI string for pbm CLI

Create the pbm user

Info

Execute this step on a primary node of each replica set. In a sharded cluster, this means on every shard replica set and the config server replica set.

1. Create the role that allows any action on any resource.

   db.getSiblingDB("admin").createRole({ "role": "pbmAnyAction",
         "privileges": [
            { "resource": { "anyResource": true },
              "actions": [ "anyAction" ]
            }
         ],
         "roles": []
      });
   

2. Create the user and assign the role you created to it.

   db.getSiblingDB("admin").createUser({user: "pbmuser",
          "pwd": "secretpwd",
          "roles" : [
             { "db" : "admin", "role" : "readWrite", "collection": "" },
             { "db" : "admin", "role" : "backup" },
             { "db" : "admin", "role" : "clusterMonitor" },
             { "db" : "admin", "role" : "restore" },
             { "db" : "admin", "role" : "pbmAnyAction" }
          ]
       });
   

You can specify the username and password values and other options of the createUser command as you require so long as the roles shown above are granted.

Tip

To list all the host+port lists for the shard replica sets in a cluster, run the following command:

db.getSiblingDB(“config”).shards.find({}, {“host”: true, “_id”: false}) 

The replica set name at the front of these “host” strings will have to be placed as a “/?replicaSet=xxxx” argument in the parameters part of the connection URI (see below).

Set the MongoDB connection URI for pbm-agent

Info

Execute this step on each node where pbm-agent is installed.

Important

Each pbm-agent process needs to connect to its localhost mongod node with a standalone type of connection. Avoid using the replica set URI with pbm-agent as it can lead to unexpected behaviour.

For sharded clusters, pbm-agent on each shard member also need to be able to connect to the config server replica set. The agents auto-discover the config server URI by querying the db.system.version collection.

Note that the MongoDB connection URI for pbm-agent is different from the connection string required by pbm CLI.

The pbm-agent.service systemd unit file includes the location of the environment file. You set the MongoDB URI connection string for the PBM_MONGODB_URI variable within the environment file for every pbm-agent.

How to find the environment file

In Ubuntu and Debian, the pbm-agent.service systemd unit file is at the path /lib/systemd/system/pbm-agent.service.

In Red Hat and CentOS, the path to this file is /usr/lib/systemd/system/pbm-agent.service.

Example of pbm-agent.service systemd unit file

[Unit]
Description=pbm-agent
After=time-sync.target network.target

[Service]
EnvironmentFile=-/etc/default/pbm-agent
Type=simple
User=pbm
Group=pbm
PermissionsStartOnly=true
ExecStart=/usr/bin/pbm-agent

[Install]
WantedBy=multi-user.target

On Debian and Ubuntu On Red Hat Enterprise Linux and derivatives

Edit the environment file /etc/default/pbm-agent and specify the MongoDB connection URI string for the pbm user to the local mongod node.

For example, if mongod node listens on port 27017, the MongoDB connection URI string will be the following:

PBM_MONGODB_URI="mongodb://pbmuser:secretpwd@localhost:27017/?authSource=admin"

Edit the environment file /etc/sysconfig/pbm-agent and specify the MongoDB connection URI string for the pbm user to the local mongod node.

For example, if mongod node listens on port 27017, the MongoDB connection URI string will be the following:

PBM_MONGODB_URI="mongodb://pbmuser:secretpwd@localhost:27017/?authSource=admin"

To improve the security of the file, you can change its owner to the user that is configured in systemd, and set the file permission so that only the owner and root can read from it.

Passwords with special characters

If the password includes special characters like #, @, / and so on, you must convert these characters using the percent-encoding mechanism when passing them to Percona Backup for MongoDB. For example, the password secret#pwd should be passed as follows in PBM_MONGODB_URI:

PBM_MONGODB_URI="mongodb://pbmuser:secret%23pwd@localhost:27017/?authSource=admin"

Set the MongoDB connection URI for pbm CLI

Info

Execute this step only on a host at which you will use pbm CLI.

Important

The pbm CLI needs to connect to the replica set that stores PBM Control Collections. The MongoDB connection URI format is different from the one required by pbm-agent.

In a non-sharded replica set it is simply that replica set. In a sharded cluster it is the config server replica set.

Set the MongoDB URI connection string for pbm CLI in your shell. This allows you to call pbm commands without the --mongodb-uri flag.

Use the following command:

export PBM_MONGODB_URI="mongodb://pbmuser:secretpwd@localhost:27017/?authSource=admin&replSetName=xxxx"

For more information about what connection string to specify, refer to the pbm connection string section.

If you are using external authentication methods in MongoDB, see External authentication support in Percona Backup for MongoDB section for configuration guidelines.

Next steps

Configure backup storage

---

Last update: February 20, 2025
Created: February 20, 2025