This is a part of the rsyslog.conf documentation.

Global Directives

All global directives need to be specified on a line by their own and must start with a dollar-sign. Here is a list in alphabetical order. Follow links for a description.

Please note that not all directives here are actually global. Some affect only the next action. This documentation will be changed soon.

Not all directives have an in-depth description right now. Default values for them are in bold. A more in-depth description will appear as implementation progresses.

Be sure to read information about queues in rsyslog - many parameter settings modify queue parameters. If in doubt, use the default, it is usually well-chosen and applicable in most cases.

• $ActionExecOnlyWhenPreviousIsSuspended
• $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)
• $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.
• $ActionFileDefaultTemplate [templateName] - sets a new default template for file actions
• $ActionFileEnableSync [on/off] - enables file syncing capability of omfile
• $ActionForwardDefaultTemplate [templateName] - sets a new default template for UDP and plain TCP forwarding action
• $ActionGSSForwardDefaultTemplate [templateName] - sets a new default template for GSS-API forwarding action
• $ActionQueueCheckpointInterval <number>
• $ActionQueueDequeueSlowdown <number> [number is timeout in microseconds (1000000us is 1sec!), default 0 (no delay). Simple rate-limiting!]
• $ActionQueueDiscardMark <number> [default 9750]
• $ActionQueueDiscardSeverity <number> [*numerical* severity! default 4 (warning)]
• $ActionQueueFileName <name>
• $ActionQueueHighWaterMark <number> [default 8000]
• $ActionQueueImmediateShutdown [on/off]
• $ActionQueueSize <number>
• $ActionQueueLowWaterMark <number> [default 2000]
• $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 indefinite]
• $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
• $ActionResumeInterval
• $ActionResumeRetryCount <number> [default 0, -1 means eternal]
• $ActionSendResendLastMsgOnReconn <[on/off]> specifies if the last message is to be resend when a connecition broken and has been reconnedcted. 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 (driver-specific)
• $ActionSendStreamDriverPermittedPeer <ID>,  accepted fingerprint (SHA1) or name of remote peer (driver-specific) - directive may go away!
• $AllowedSender
• $ControlCharacterEscapePrefix
• $DebugPrintCFSyslineHandlerList
• $DebugPrintModuleList
• $DebugPrintTemplateList
• $DefaultNetstreamDriver <drivername>, the default network stream driver to use. Defaults to ptcp.$DefaultNetstreamDriverCAFile </path/to/cafile.pem>
• $DefaultNetstreamDriverCertFile </path/to/certfile.pem>
• $DefaultNetstreamDriverKeyFile </path/to/keyfile.pem>
• $DirCreateMode
• $DirGroup
• $DirOwner
• $DropMsgsWithMaliciousDnsPTRRecords
• $DropTrailingLFOnReception
• $DynaFileCacheSize
• $EscapeControlCharactersOnReceive
• $ErrorMessagesToStderr [on|off] - direct rsyslogd error message to stderr (in addition to other targets)
• $FailOnChownFailure
• $FileCreateMode
• $FileGroup
• $FileOwner
• $GssForwardServiceName
• $GssListenServiceName
• $GssMode
• $HUPisRestart [on/off] - if set to on, a HUP is a full daemon restart. This means any queued messages are discarded (depending on queue configuration, of course) all modules are unloaded and reloaded. This mode keeps compatible with sysklogd, but is not recommended for use with rsyslog. To do a full restart, simply stop and start the daemon. The default is "on" for compatibility reasons. If it is set to "off", a HUP will only close open files. This is a much quicker action and usually the only one that is needed e.g. for log rotation. It is recommended to set the setting to "off".
• $IncludeConfig
• MainMsgQueueCheckpointInterval <number>
• $MainMsgQueueDequeueSlowdown <number> [number is timeout in microseconds (1000000us is 1sec!), default 0 (no delay). Simple rate-limiting!]
• $MainMsgQueueDiscardMark <number> [default 9750]
• $MainMsgQueueDiscardSeverity <severity> [either a textual or numerical severity! default 4 (warning)]
• $MainMsgQueueFileName <name>
• $MainMsgQueueHighWaterMark <number> [default 8000]
• $MainMsgQueueImmediateShutdown [on/off]
• $MainMsgQueueSize
• $MainMsgQueueLowWaterMark <number> [default 2000]
• $MainMsgQueueMaxFileSize <size_nbr>, default 1m
• $MainMsgQueueTimeoutActionCompletion <number> [number is timeout in ms (1000ms is 1sec!), default 1000, 0 means immediate!]
• $MainMsgQueueTimeoutEnqueue <number> [number is timeout in ms (1000ms is 1sec!), default 2000, 0 means indefinite]
• $MainMsgQueueTimeoutShutdown <number> [number is timeout in ms (1000ms is 1sec!), default 0 (indefinite)]
• $MainMsgQueueWorkerTimeoutThreadShutdown <number> [number is timeout in ms (1000ms is 1sec!), default 60000 (1 minute)]
• $MainMsgQueueType [FixedArray/LinkedList/Direct/Disk]
• $MainMsgQueueSaveOnShutdown  [on/off]
• $MainMsgQueueWorkerThreads <number>, num worker threads, default 1, recommended 1
• $MainMsgQueueWorkerThreadMinumumMessages <number>, default 100
• $MarkMessagePeriod (immark)
• $MaxMessageSize <size_nbr>, default 2k - allows to specify maximum supported message size (both for sending and receiving). The default should be sufficient for almost all cases. Do not set this below 1k, as it would cause interoperability problems with other syslog implementations.
  Change the setting to e.g. 32768 if you would like to support large message sizes for IHE (32k is the current maximum needed for IHE). I was initially tempted to set the default to 32k, but there is a some memory footprint with the current implementation in rsyslog.
  If you intend to receive Windows Event Log data (e.g. via EventReporter), you might want to increase this number to an even higher value, as event log messages can be very lengthy ("$MaxMessageSize 64k" is not a bad idea). Note: testing showed that 4k seems to be the typical maximum for UDP based syslog. This is an IP stack restriction. Not always ... but very often. If you go beyond that value, be sure to test that rsyslogd actually does what you think it should do ;) It is highly suggested to use a TCP based transport instead of UDP (plain TCP syslog, RELP). This resolves the UDP stack size restrictions.
  Note that 2k, the current default, is the smallest size that must be supported in order to be compliant to the upcoming new syslog RFC series.
• $ModDir
• $ModLoad
• $RepeatedMsgReduction
• $ResetConfigVariables
• $OptimizeForUniprocessor [on/off] - turns on optimizatons which lead to better performance on uniprocessors. If you run on multicore-machiens, turning this off lessens CPU load. The default may change as uniprocessor systems become less common.
• $PreserveFQDN [on/off) - if set to off (legacy default to remain compatible to sysklogd), the domain part from a name that is within the same domain as the receiving system is stripped. If set to on, full names are always used.
• $WorkDirectory <name> (directory for spool and other work files)
• $UDPServerAddress <IP> (imudp) -- local IP address (or name) the UDP listens should bind to
• $UDPServerRun <port> (imudp) -- former -r<port> option, default 514, start UDP server on this port, "*" means all addresses
• $UDPServerTimeRequery <nbr-of-times> (imudp) -- this is a performance optimization. Getting the system time is very costly. With this setting, imudp can be instructed to obtain the precise time only once every n-times. This logic is only activated if messages come in at a very fast rate, so doing less frequent time calls should usually be acceptable. The default value is two, because we have seen that even without optimization the kernel often returns twice the identical time. You can set this value as high as you like, but do so at your own risk. The higher the value, the less precise the timestamp.
• $PrivDropToGroup
• $PrivDropToGroupID
• $PrivDropToUser
• $PrivDropToUserID

Where <size_nbr> is specified above, modifiers can be used after the number part. For example, 1k means 1024. Supported are k(ilo), m(ega), g(iga), t(era), p(eta) and e(xa). Lower case letters refer to the traditional binary defintion (e.g. 1m equals 1,048,576) whereas upper case letters refer to their new 1000-based definition (e.g 1M equals 1,000,000).

Numbers may include '.' and ',' for readability. So you can for example specify either "1000" or "1,000" with the same result. Please note that rsyslogd simply ignores the punctuation. Form it's point of view, "1,,0.0.,.,0" also has the value 1000.

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This documentation is part of the rsyslog project.
Copyright © 2008 by Rainer Gerhards and Adiscon. Released under the GNU GPL version 2 or higher.