Legacy Action-Specific Configuration Statements

Statements modify the next action(s) that is/are defined via legacy syntax after the respective statement. Actions defined via the action() object are not affected by the legacy statements listed here. Use the action() object properties instead.

Generic action configuration Statements

These statements can be used with all types of actions.

  • $ActionName <a_single_word> - used primarily for documentation, e.g. when generating a configuration graph. Available sice 4.3.1.
  • $ActionExecOnlyOnceEveryInterval <seconds> - execute action only if the last execute is at last <seconds> seconds in the past (more info in ommail, but may be used with any action). To disable this setting, use value 0.
  • $ActionExecOnlyEveryNthTime <number> - If configured, the next action will only be executed every n-th time. For example, if configured to 3, the first two messages that go into the action will be dropped, the 3rd will actually cause the action to execute, the 4th and 5th will be dropped, the 6th executed under the action, … and so on. Note: this setting is automatically re-set when the actual action is defined.
  • $ActionExecOnlyEveryNthTimeTimeout <number-of-seconds> - has a meaning only if $ActionExecOnlyEveryNthTime is also configured for the same action. If so, the timeout setting specifies after which period the counting of “previous actions” expires and a new action count is begun. Specify 0 (the default) to disable timeouts. Why is this option needed? Consider this case: a message comes in at, eg., 10am. That’s count 1. Then, nothing happens for the next 10 hours. At 8pm, the next one occurs. That’s count 2. Another 5 hours later, the next message occurs, bringing the total count to 3. Thus, this message now triggers the rule. The question is if this is desired behavior? Or should the rule only be triggered if the messages occur within an e.g. 20 minute window? If the later is the case, you need a $ActionExecOnlyEveryNthTimeTimeout 1200 This directive will timeout previous messages seen if they are older than 20 minutes. In the example above, the count would now be always 1 and consequently no rule would ever be triggered.
  • $ActionResumeRetryCount <number> [default 0, -1 means eternal]
  • $ActionWriteAllMarkMessages [on/off]- [available since 5.1.5] - normally, mark messages are written to actions only if the action was not recently executed (by default, recently means within the past 20 minutes). If this setting is switched to “on”, mark messages are always sent to actions, no matter how recently they have been executed. In this mode, mark messages can be used as a kind of heartbeat. Note that this option auto-resets to “off”, so if you intend to use it with multiple actions, it must be specified in front off all selector lines that should provide this functionality.

omfile-specific Configuration Statements

These statements are specific to omfile-based actions.

  • $CreateDirs [on/off] - create directories on an as-needed basis
  • $ActionFileDefaultTemplate [templateName] - sets a new default template for file actions
  • $ActionFileEnableSync [on/off] - enables file syncing capability of omfile
  • $OMFileAsyncWriting [on/off], if turned on, the files will be written in asynchronous mode via a separate thread. In that case, double buffers will be used so that one buffer can be filled while the other buffer is being written. Note that in order to enable $OMFileFlushInterval, $OMFileAsyncWriting must be set to “on”. Otherwise, the flush interval will be ignored. Also note that when $OMFileFlushOnTXEnd is “on” but $OMFileAsyncWriting is off, output will only be written when the buffer is full. This may take several hours, or even require a rsyslog shutdown. However, a buffer flush can be forced in that case by sending rsyslogd a HUP signal.
  • $OMFileZipLevel 0..9 [default 0] - if greater 0, turns on gzip compression of the output file. The higher the number, the better the compression, but also the more CPU is required for zipping.
  • $OMFileIOBufferSize <size_nbr>, default 4k, size of the buffer used to writing output data. The larger the buffer, the potentially better performance is. The default of 4k is quite conservative, it is useful to go up to 64k, and 128K if you used gzip compression (then, even higher sizes may make sense)
  • $OMFileFlushOnTXEnd <[on/off]>, default on. Omfile has the capability to write output using a buffered writer. Disk writes are only done when the buffer is full. So if an error happens during that write, data is potentially lost. In cases where this is unacceptable, set $OMFileFlushOnTXEnd to on. Then, data is written at the end of each transaction (for pre-v5 this means after each log message) and the usual error recovery thus can handle write errors without data loss. Note that this option severely reduces the effect of zip compression and should be switched to off for that use case. Note that the default -on- is primarily an aid to preserve the traditional syslogd behaviour.

omfwd-specific Configuration Statements

These statements are specific to omfwd-based actions.

  • $ActionForwardDefaultTemplate [templateName] - sets a new default template for UDP and plain TCP forwarding action
  • $ActionSendResendLastMsgOnReconnect <[on/off]> specifies if the last message is to be resend when a connecition breaks and has been reconnected. May increase reliability, but comes at the risk of message duplication.
  • $ActionSendStreamDriver <driver basename> just like $DefaultNetstreamDriver, but for the specific action
  • $ActionSendStreamDriverMode <mode>, default 0, mode to use with the stream driver (driver-specific)
  • $ActionSendStreamDriverAuthMode <mode>,  authentication mode to use with the stream driver. Note that this directive requires TLS netstream drivers. For all others, it will be ignored. (driver-specific)
  • $ActionSendStreamDriverPermittedPeer <ID>,  accepted fingerprint (SHA1) or name of remote peer. Note that this directive requires TLS netstream drivers. For all others, it will be ignored. (driver-specific) - directive may go away!
  • $ActionSendTCPRebindInterval nbr- [available since 4.5.1] - instructs the TCP send action to close and re-open the connection to the remote host every nbr of messages sent. Zero, the default, means that no such processing is done. This directive is useful for use with load-balancers. Note that there is some performance overhead associated with it, so it is advisable to not too often “rebind” the connection (what “too often” actually means depends on your configuration, a rule of thumb is that it should be not be much more often than once per second).
  • $ActionSendUDPRebindInterval nbr- [available since 4.3.2] - instructs the UDP send action to rebind the send socket every nbr of messages sent. Zero, the default, means that no rebind is done. This directive is useful for use with load-balancers.

omgssapi-specific Configuration Statements

These statements are specific to omgssapi actions.

action-queue specific Configuration Statements

The following statements specify parameters for the action queue. To understand queue parameters, read queues in rsyslog.

Action queue parameters usually affect the next action and auto-reset to defaults thereafter. Most importantly, this means that when a “real” (non-direct) queue type is defined, this affects the immediately following action, only. The next and all other actions will be in “direct” mode (no real queue) if not explicitely specified otherwise.

  • $ActionQueueCheckpointInterval <number>
  • $ActionQueueDequeueBatchSize <number> [default 128]
  • $ActionQueueDequeueSlowdown <number> [number is timeout in microseconds (1000000us is 1sec!), default 0 (no delay). Simple rate-limiting!]
  • $ActionQueueDiscardMark <number> [default 80% of queue size]
  • $ActionQueueDiscardSeverity <number> [*numerical* severity! default 8 (nothing discarded)]
  • $ActionQueueFileName <name>
  • $ActionQueueHighWaterMark <number> [default 90% of queue size]
  • $ActionQueueImmediateShutdown [on/off]
  • $ActionQueueSize <number>
  • $ActionQueueLowWaterMark <number> [default 70% of queue size]
  • $ActionQueueMaxFileSize <size_nbr>, default 1m
  • $ActionQueueTimeoutActionCompletion <number> [number is timeout in ms (1000ms is 1sec!), default 1000, 0 means immediate!]
  • $ActionQueueTimeoutEnqueue <number> [number is timeout in ms (1000ms is 1sec!), default 2000, 0 means discard immediately]
  • $ActionQueueTimeoutShutdown <number> [number is timeout in ms (1000ms is 1sec!), default 0 (indefinite)]
  • $ActionQueueWorkerTimeoutThreadShutdown <number> [number is timeout in ms (1000ms is 1sec!), default 60000 (1 minute)]
  • $ActionQueueType [FixedArray/LinkedList/Direct/Disk]
  • $ActionQueueSaveOnShutdown  [on/off]
  • $ActionQueueWorkerThreads <number>, num worker threads, default 1, recommended 1
  • $ActionQueueWorkerThreadMinumumMessages <number>, default 100
  • $ActionGSSForwardDefaultTemplate [templateName] - sets a new default template for GSS-API forwarding action

See also

Help with configuring/using Rsyslog:

  • Mailing list - best route for general questions
  • GitHub: rsyslog source project - detailed questions, reporting issues that are believed to be bugs with Rsyslog
  • Stack Exchange (View, Ask) - experimental support from rsyslog community

See also

Contributing to Rsyslog:

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