imklog: Kernel Log Input Module

Reads messages from the kernel log and submits them to the syslog engine.

Author:Rainer Gerhards <>

Configuration Directives

$KLogInternalMsgFacility <facility>

The facility which messages internally generated by imklog will have. imklog generates some messages of itself (e.g. on problems, startup and shutdown) and these do not stem from the kernel. Historically, under Linux, these too have “kern” facility. Thus, on Linux platforms the default is “kern” while on others it is “syslogd”. You usually do not need to specify this configuration directive - it is included primarily for few limited cases where it is needed for good reason. Bottom line: if you don’t have a good idea why you should use this setting, do not touch it.

$KLogPermitNonKernelFacility off

At least under BSD the kernel log may contain entries with non-kernel facilities. This setting controls how those are handled. The default is “off”, in which case these messages are ignored. Switch it to on to submit non-kernel messages to rsyslog processing.

$DebugPrintKernelSymbols on/off

Linux only, ignored on other platforms (but may be specified). Defaults to off.

$klogLocalIPIF [interface name]

If provided, the IP of the specified interface (e.g. “eth0”) shall be used as fromhost-ip for imklog-originating messages. If this directive is not given OR the interface cannot be found (or has no IP address), the default of “” is used.

$klogConsoleLogLevel <number>

Sets the console log level. If specified, only messages with up to the specified level are printed to the console. The default is -1, which means that the current settings are not modified. To get this behavior, do not specify $klogConsoleLogLevel in the configuration file. Note that this is a global parameter. Each time it is changed, the previous definition is re-set. The one activate will be that one that is active when imklog actually starts processing. In short words: do not specify this directive more than once!

Linux only, ignored on other platforms (but may be specified)

$klogUseSyscallInterface on/off

Linux only, ignored on other platforms (but may be specified). Defaults to off.

$klogSymbolsTwice on/off

Linux only, ignored on other platforms (but may be specified). Defaults to off.

$klogParseKernelTimestamp on/off

If enabled and the kernel creates a timestamp for its log messages, this timestamp will be parsed and converted into regular message time instead to use the receive time of the kernel message (as in 5.8.x and before). Default is ‘off’ to prevent parsing the kernel timestamp, because the clock used by the kernel to create the timestamps is not supposed to be as accurate as the monotonic clock required to convert it. Depending on the hardware and kernel, it can result in message time differences between kernel and system messages which occurred at same time.

$klogKeepKernelTimestamp on/off

If enabled, this option causes to keep the [timestamp] provided by the kernel at the begin of in each message rather than to remove it, when it could be parsed and converted into local time for use as regular message time. Only used, when $klogParseKernelTimestamp is on.

Caveats/Known Bugs

This is obviously platform specific and requires platform drivers. Currently, imklog functionality is available on Linux and BSD.

This module is not supported on Solaris and not needed there. For Solaris kernel input, use imsolaris.


The following sample pulls messages from the kernel log. All parameters are left by default, which is usually a good idea. Please note that loading the plugin is sufficient to activate it. No directive is needed to start pulling kernel messages.

$ModLoad imklog

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