The Systemd input plugin allows to collect log messages from the Journald daemon on Linux environments.
The plugin supports the following configuration parameters:
| Key | Description | Default |
|---|---|---|
In order to receive Systemd messages, you can run the plugin from the command line or through the configuration file:
From the command line you can let Fluent Bit listen for Systemd messages with the following options:
In the example above we are collecting all messages coming from the Docker service.
In your main configuration file append the following Input & Output sections:
Path
Optional path to the Systemd journal directory, if not set, the plugin will use default paths to read local-only logs.
Max_Fields
Set a maximum number of fields (keys) allowed per record.
8000
Max_Entries
When Fluent Bit starts, the Journal might have a high number of logs in the queue. In order to avoid delays and reduce memory usage, this option allows to specify the maximum number of log entries that can be processed per round. Once the limit is reached, Fluent Bit will continue processing the remaining log entries once Journald performs the notification.
5000
Systemd_Filter
Allows to perform a query over logs that contains a specific Journald key/value pairs, e.g: _SYSTEMD_UNIT=UNIT. The Systemd_Filter option can be specified multiple times in the input section to apply multiple filters as required.
Systemd_Filter_Type
Define the filter type when Systemd_Filter is specified multiple times. Allowed values are And and Or. With And a record is matched only when all of the Systemd_Filter have a match. With Or a record is matched when any of the Systemd_Filter has a match.
Or
Tag
The tag is used to route messages but on Systemd plugin there is an extra functionality: if the tag includes a star/wildcard, it will be expanded with the Systemd Unit file (_SYSTEMD_UNIT, e.g. host.* => host.UNIT_NAME) or unknown (e.g. host.unknown) if _SYSTEMD_UNIT is missing.
DB
Specify the absolute path of a database file to keep track of Journald cursor.
DB.Sync
Set a default synchronization (I/O) method. values: Extra, Full, Normal, Off. This flag affects how the internal SQLite engine do synchronization to disk, for more details about each option please refer to this section. note: this option was introduced on Fluent Bit v1.4.6.
Full
Read_From_Tail
Start reading new entries. Skip entries already stored in Journald.
Off
Lowercase
Lowercase the Journald field (key).
Off
Strip_Underscores
Remove the leading underscore of the Journald field (key). For example the Journald field _PID becomes the key PID.
Off
Threaded
Indicates whether to run this input in its own thread.
false