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Auditing allows administrators to track and log user activity on a MongoDB server. With auditing enabled, the server will generate an audit log file. This file contains information about different user events including authentication, authorization failures, and so on.

To enable audit logging, specify where to send audit events using the --auditDestination option on the command line or the auditLog.destination variable in the configuration file.

If you want to output events to a file, also specify the format of the file using the --auditFormat option or the auditLog.format variable, and the path to the file using the --auditPath option or the auditLog.path variable.

To filter recorded events, use the --auditFilter option or the auditLog.filter variable.

For example, to log only events from a user named tim and write them to a JSON file /var/log/psmdb/audit.json, start the server with the following parameters:

mongod \
 --dbpath data/db
 --auditDestination file \
 --auditFormat JSON \
 --auditPath /var/log/psmdb/audit.json \
 --auditFilter '{ "users.user" : "tim" }'

The options in the previous example can be used as variables in the MongoDB configuration file:

  dbPath: data/db
  destination: file
  format: JSON
  path: /var/log/psmdb/audit.json
  filter: '{ "users.user" : "tim" }'


If you start the server with auditing enabled, it cannot be disabled dynamically during runtime.

Audit Options

The following options control audit logging:

option --auditDestination

Enables auditing and specifies where to send audit events:

  • console: Output audit events to stdout.
  • file: Output audit events to a file specified by the --auditPath` option in a format specified by the :option:--auditFormat option.
  • syslog: Output audit events to syslog.
option --auditFilter

Specifies a filter to apply to incoming audit events, enabling the administrator to only capture a subset of them. The value must be interpreted as a query object with the following syntax:

{ <field1>: <expression1>, ... }

Audit log events that match this query will be logged. Events that do not match this query will be ignored.

For more information, see Audit Filter Examples.

option --auditFormat

Specifies the format of the audit log file, if you set the --auditDestination option to file.

The default value is JSON. Alternatively, you can set it to BSON.

option --auditPath

Specifies the fully qualified path to the file where audit log events are written, if you set the --auditDestination option to file.

If this option is not specified, then the auditLog.json file is created in the server’s configured log path. If log path is not configured on the server, then the auditLog.json file is created in the current directory (from which mongod was started).


This file will rotate in the same manner as the system log path, either on server reboot or using the logRotate command. The time of rotation will be added to the old file’s name.

Audit Message Syntax

Audit logging writes messages in JSON format with the following syntax:

  atype: <String>,
  ts : { "$date": <timestamp> },
  local: { ip: <String>, port: <int> },
  remote: { ip: <String>, port: <int> },
  users : [ { user: <String>, db: <String> }, ... ],
  roles: [ { role: <String>, db: <String> }, ... ],
  param: <document>,
  result: <int>
atype:Event type
ts:Date and UTC time of the event
local:Local IP address and port number of the instance
remote:Remote IP address and port number of the incoming connection associated with the event
users:Users associated with the event
roles:Roles granted to the user
param:Details of the event associated with the specific type
result:Exit code (0 for success)

Audit Filter Examples

The following examples demostrate the flexibility of audit log filters.

Basic Filtering

For example, you can log actions only from user john on all databases:

  • Command line:

    --auditDestination file --auditFilter '{ "users.user": "john" }'
  • Config file:

      destination: file
      filter: '{ "users.user": "john" }'

Standard Query Selectors

You can use query selectors, such as $eq, $in, $gt, $lt, $ne, and others to log multiple event types.

For example, to log only the dropCollection and dropDatabase events:

  • Command line:

    --auditDestination file --auditFilter '{ atype: { $in: [ "dropCollection", "dropDatabase" ] } }'
  • Config file:

      destination: file
      filter: '{ atype: { $in: [ "dropCollection", "dropDatabase" ] } }'

Regular Expressions

Another way to specify multiple event types is using regular expressions.

For example, to filter all drop operations:

  • Command line:

    --auditDestination file --auditFilter '{ "atype" : /^drop.*/ }'
  • Config file:

      destination: file
      filter: '{ "atype" : /^drop.*/ }'

Read and Write Operations

By default, operations with successful authorization are not logged, so for this filter to work, enable auditAuthorizationSuccess parameter, as described in Enabling Auditing of Authorization Success.

For example, to filter read and write operations on all the collections in the test database:


The dot (.) after the database name in the regular expression must be escaped with two backslashes (\\).

  • Command line:

    --setParameter auditAuthorizationSuccess=true --auditDestination file --auditFilter '{ atype: "authCheck", "param.command": { $in: [ "find", "insert", "delete", "update", "findandmodify" ] }, "param.ns": /^test\\./ } }'
  • Config file:

      destination: file
      filter: '{ atype: "authCheck", "param.command": { $in: [ "find", "insert", "delete", "update", "findandmodify" ] }, "param.ns": /^test\\./ } }'
    setParameter: { auditAuthorizationSuccess: true }

Enabling Auditing of Authorization Success

By default, only authorization failures for the authCheck action are logged by the audit system. To enable logging of authorization successes, set the auditAuthorizationSuccess parameter to true.


Enabling this parameter is required if you want to filter CRUD operations in the audit log, because CRUD operations are logged under authCheck action.

You can enable it on a running server using the following command:

db.adminCommand( { setParameter: 1, auditAuthorizationSuccess: true } )

To enable it on the command line, use the following option when running mongod or mongos process:

--setParameter auditAuthorizationSuccess=true

You can also add it to the configuration file as follows:

  auditAuthorizationSuccess: true


Enabling auditAuthorizationSuccess can impact performance compared to logging only authorization failures.

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