Data Collection

MongoDB ReplicaSet Output Plugin

The out_mongo_replset Buffered Output plugin writes records into MongoDB, the emerging document-oriented database system.

NOTE: This plugin is for users using ReplicaSet. If you are not using ReplicaSet, please see the out_mongo article instead.

Why Fluentd with MongoDB?

Fluentd enables your apps to insert records to MongoDB asynchronously with batch-insertion, unlike direct insertion of records from your apps. This has the following advantages:

less impact on application performance
higher MongoDB insertion throughput while maintaining JSON record structure

Install

out_mongo_replset is included in td-agent by default. Fluentd gem users will need to install the fluent-plugin-mongo gem using the following command.

$ fluent-gem install fluent-plugin-mongo

Example Configuration

# Single MongoDB
<match mongo.**>
  type mongo_replset
  database fluentd
  collection test
  nodes localhost:27017,localhost:27018,localhost:27019

  # flush
  flush_interval 10s
</match>

Please see the Store Apache Logs into MongoDB article for real-world use cases.

NOTE: Please see the Config File article for the basic structure and syntax of the configuration file.

Parameters

type (required)

The value must be mongo.

nodes (required)

The comma separated node strings (e.g. host1:27017,host2:27017,host3:27017).

database (required)

The database name.

collection (required if not tag_mapped)

The collection name.

capped

This option enables capped collection. This is always recommended because MongoDB is not suited to storing large amounts of historical data.

capped_size

Sets the capped collection size.

user

The username to use for authentication.

password

The password to use for authentication.

tag_mapped

This option will allow out_mongo to use Fluentd's tag to determine the destination collection.

For example, if you generate records with tags 'mongo.foo', the records will be inserted into the foo collection within the fluentd database.

<match mongo.*>
  type mongo_replset
  database fluentd
  nodes localhost:27017,localhost:27018,localhost:27019

  # Set 'tag_mapped' if you want to use tag mapped mode.
  tag_mapped

  # If the tag is "mongo.foo", then the prefix "mongo." is removed.
  # The inserted collection name is "foo".
  remove_tag_prefix mongo.

  # This configuration is used if the tag is not found. The default is 'untagged'.
  collection misc
</match>

name

The ReplicaSet name.

read

The ReplicaSet read preference (e.g. secondary, etc).

refresh_mode

The ReplicaSet refresh mode (e.g. sync, etc).

refresh_interval

The ReplicaSet refresh interval.

num_retries

The ReplicaSet failover threshold. The default threshold is 60. If the retry count reaches this threshold, the plugin raises an exception.

INCLUDE: _buffer_parameters

INCLUDE: _log_level_params