Connect MongoDB instance¶

Connect a MongoDB instance to PMM to monitor a MongoDB or Percona Server for MongoDB database server.

Prerequisites¶

Before you start, ensure you have:

PMM Server installed and running with a known IP address or hostname accessible from the Client node.
PMM Client installed and the nodes are registered with PMM Server.
Admin privileges to install and configure PMM Client on the host.
Preconfigured MongoDB user with appropriate monitoring privileges, or sufficient privileges to create the required roles and users.
MongoDB server version 6.0 or higher. PMM may work with MongoDB versions as old as 4.4, but we recommend using MongoDB 6.0+ for complete feature support.

Create PMM account and set permissions¶

We recommend using a dedicated account to connect PMM Client to the monitored database instance. The permissions required depend on which PMM features you plan to use.

Run the example commands below in a mongo shell session to:

Create custom roles with the privileges required for creating/restoring backups and working with Query Analytics (QAN).
Create/update a database user with these roles, plus the built-in clusterMonitor role.

Important

Values for username (user) and password (pwd) are examples. Replace them before using these code snippets.

Monitoring and QAN privilegesFull backup management privileges

This role grants the essential minimum privileges needed for monitoring and QAN:

db.getSiblingDB("admin").createRole({
"role": "pmmMonitor",
"privileges": [
    {
    "resource": { "db": "", "collection": "" },
    "actions": [ "dbHash", "find", "listIndexes", "listCollections", "collStats", "dbStats", "indexStats" ]
    },
    {
    "resource": { "db": "", "collection": "system.version" },
    "actions": [ "find" ]
    },
    {
    "resource": { "db": "", "collection": "system.profile" },
    "actions": [ "dbStats", "collStats", "indexStats" ]
    }         
],
"roles": [ ]
})

This role provides the necessary privileges for using PMM’s backup management features. It is required only if you plan to use this feature:

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

Create/update user and assign created roles¶

Create or update a user with the minimum required privileges for monitoring by assigning the following roles:

MongoDB 8.0+MongoDB <8.0

MongoDB 8.0 introduced stricter security for direct shard access. For MongoDB 8.0 and later, the PMM user also requires the directShardOperations role to collect complete metrics from all cluster components.

db.getSiblingDB("admin").createUser({
    "user": "pmm",
    "pwd": "<SECURE_PASSWORD>",  // Replace with a secure password
    "roles": [
        { "db": "admin", "role": "pmmMonitor" },
        { "db": "local", "role": "read" },
        { "db": "admin", "role": "clusterMonitor" },
        { "db": "admin", "role": "directShardOperations" }
    ]
})

If you intend to use PMM’s backup management features, grant these additional permissions:

db.getSiblingDB("admin").createUser({
    "user": "pmm",
    "pwd": "<SECURE_PASSWORD>",  // Replace with a secure password
    "roles": [
        { "db" : "admin", "role": "pmmMonitor" },
        { "db" : "local", "role": "read" },
        { "db" : "admin", "role" : "readWrite", "collection": "" },
        { "db" : "admin", "role" : "backup" },
        { "db" : "admin", "role" : "clusterMonitor" },
        { "db" : "admin", "role" : "restore" },
        { "db" : "admin", "role" : "pbmAnyAction" },
        { "db" : "admin", "role": "directShardOperations" }
    ]
})

db.getSiblingDB("admin").createUser({
    "user": "pmm",
    "pwd": "pmm",
    "roles": [
        { "db": "admin", "role": "pmmMonitor" },
        { "db": "local", "role": "read" },
        { "db": "admin", "role": "clusterMonitor" }
    ]
})

If you intend to use PMM’s backup management features, also grant these additional permissions:

db.getSiblingDB("admin").createUser({
    "user": "pmm",
    "pwd": "pmm",
    "roles": [
        { "db" : "admin", "role": "pmmMonitor" },
        { "db" : "local", "role": "read" },
        { "db" : "admin", "role" : "readWrite", "collection": "" },
        { "db" : "admin", "role" : "backup" },
        { "db" : "admin", "role" : "clusterMonitor" },
        { "db" : "admin", "role" : "restore" },
        { "db" : "admin", "role" : "pbmAnyAction" }
    ]
})

Enable MongoDB profiling for Query Analytics (QAN)¶

To use PMM QAN, you must turn on MongoDB’s profiling feature. By default, profiling is turned off as it can adversely affect the performance of the database server.

Choose one of the following methods to enable profiling:

In MongoDB configuration file (Recommended)On CLIIn MongoDB shell (temporary)

This method ensures your settings persist across server restarts and system reboots. It’s the recommended approach for production environments:

Edit the configuration file (usually /etc/mongod.conf).
Add or modify the operationProfiling section in the configuration file. Pay close attention to indentation as YAML is whitespace-sensitive:
```
operationProfiling:
    mode: all             
    slowOpThresholdMs: 200
    rateLimit: 100        
```
These settings control the following:
- mode: all - Collects data for all operations.
- slowOpThresholdMs: 200 - Marks operations exceeding 200ms as “slow.”
- rateLimit: 100 - Limits profiling sampling rate (Percona Server for MongoDB only).
For more information about profiling configuration options, see the MongoDB documentation and the Percona Server for MongoDB documentation.
Restart the mongod service using the appropriate command for your system. For example, for systemd:
```
systemctl restart mongod
```

Use this method when starting the MongoDB server manually:

mongod --dbpath=DATABASEDIR --profile 2 --slowms 200 --rateLimit 100

--dbpath: The path to database files (usually /var/lib/mongo).
--profile: The MongoDB profiling level. A value of 2 tells the server to collect profiling data for all operations. To lower the load on the server, use a value of 1 to only record slow operations.
--slowms: An operation is classified as slow if it runs for longer than this number of milliseconds.
--rateLimit: (Only available with Percona Server for MongoDB.) The sample rate of profiled queries. A value of 100 means sample every 100^th fast query. (Read more)

Caution

Smaller values improve accuracy but can adversely affect the performance of your server.

This method enables profiling until the next server restart. Profiling must be enabled for each database you want to monitor. For example, to enable the profiler in the testdb, run this:

use testdb
db.setProfilingLevel(2, {slowms: 0})

If you have already added a service, you should remove it and re-add it after changing the profiling level.

Add MongoDB service to PMM¶

After configuring your database server, add a MongoDB service using either the user interface or the command line.

Important

To monitor MongoDB sharded clusters, PMM requires access to all cluster components. Make sure to add all config servers, shards, and at least one mongos router. Otherwise, PMM will not be able to correctly collect metrics and populate dashboards.

Via CLIVia UI

Use pmm-admin to add the database server as a service using one of these example commands:

Basic MongoDB instanceSharded cluster componentSSL/TLS secured MongoDB

pmm-admin add mongodb \
--username=pmm \
--password=your_secure_password

pmm-admin add mongodb \
--username=pmm \
--password=your_secure_password \
--cluster=my_cluster_name \
--replication-set=rs1  # Optional: specify replication set name

pmm-admin add mongodb \
--username=pmm \
--password=your_secure_password \
--tls \
--tls-certificate-key-file=/path/to/client.pem \
--tls-certificate-key-file-password=cert_password \  # If certificate has password
--tls-ca-file=/path/to/ca.pem \
--authentication-mechanism=MONGODB-X509 \  # For X.509 authentication
--authentication-database=$external      # For X.509 authentication

When successful, PMM Client will print MongoDB Service added with the service’s ID and name. Use the --environment and --custom-labels options to set tags for the service to help identify them.

Tips

When adding nodes to a sharded cluster, ensure to add each node separately using the --cluster mycluster option. This allows the MongoDB Cluster Summary dashboard to populate correctly.
You can also use the --replication-set option to specify a replication set. For instance, you can use --replication-set config for your config servers; --replication-set rs1 for your servers in the first replica set, --replication-set rs2 for your servers in the second replica set, and so on.
When running mongos routers in containers, specify the diagnosticDataCollectionDirectoryPath to ensure that pmm-agent can properly capture mongos metrics. For example: mongos --setParameter diagnosticDataCollectionDirectoryPath=/var/log/mongo/mongos.diagnostic.data/

To add a service with the UI:

Select PMM Configuration > Add Service > MongoDB.
Fill in the required fields.
Click Add service.

Verify MongoDB Service Configuration¶

After adding MongoDB service to PMM, verify that it’s properly configured and collecting data. This ensures your monitoring setup is working correctly.

Check service registration:
Via CLIVia UI
Look for your service in the output of this command:
pmm-admin list
To check the service from the UI:
- Select PMM Configuration > Inventory > Services.
- Find your MongoDB service in the list and verify it shows Active status.
- Verify the Service name, Addresses, and other connection details are correct.
- In the Options column, expand the Details section to check that agents are properly connected.
Verify data collection:
- Open the MongoDB Instances Overview dashboard.
- Set the Service Name to the newly-added service.
- Confirm that metrics are being displayed in the dashboard.
Verify Query Analytics for the service:
- Open PMM Query Analytics dashboard and use the filters to select your MongoDB service.
- Check that query data is visible (it may take a few minutes for data to appear after initial setup).

Remove MongoDB Service¶

If you need to remove MongoDB service from PMM, follow these steps:

Via CLIVia UI

Replace SERVICE_NAME with the name you used when adding the service. You can list all services with pmm-admin:

pmm-admin remove mongodb SERVICE_NAME

To remove the services through the PMM interface:

Go to PMM Configuration > Inventory > Services.
In the Status column, check the box for the service you want to remove and click Delete.
On the confirmation pop-up, click Delete service and select Force mode if you want to also delete associated Clients.