Kernel Log Input Module (imklog)

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# Kernel Log Input Module

Module Name: imklog

Author: Rainer Gerhards <rgerhards@adiscon.com>

Description:

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

Configuration Directives:

- LogPath
  The path to the Kernel log. This value should only be changed if you really know what you are doing.
- InternalMsgFacility <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 configuratin 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.
- PermitNonKernelFacility [on/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.
- ParseKernelTimeStamp [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 to not parse 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.
- KeepKernelTimeStamp [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 ParseKernelTimestamp is on.
- ConsoleLogLevel [number] (former klogd -c option) -- 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 ConsoleLogLevel 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!

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.

Sample:

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.

module(load="imklog")

Legacy Configuration Directives:

- $KLogInternalMsgFacility <facility>
  equivalent to: InternalMsgFacility
- $KLogPermitNonKernelFacility [on/off]
  equivalent to: PermitNonKernelFacility
- $DebugPrintKernelSymbols [on/off]
  Linux only, ignored on other platforms (but may be specified)
- $klogLocalIPIF [interface name] - (available since 5.9.6) - 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 "127.0.0.1" is used.
- $klogSymbolLookup [on/off] -- disables imklog kernel symbol translation (former klogd -x option). NOTE that this option is counter-productive on recent kernels (>= 2.6) because the kernel already does the symbol translation and this option breaks the information.
  This option is scheduled for removal, probably with version 4.x. Do not use it except if you have a very good reason. If you have one, let us know because otherwise new versions will no longer support it.
  Linux only, ignored on other platforms (but may be specified)
- $klogConsoleLogLevel [number]
  equivalent to: ConsoleLogLevel
- $klogUseSyscallInterface [on/off] -- former klogd -s option
  Linux only, ignored on other platforms (but may be specified)
- $klogSymbolsTwice [on/off] -- former klogd -2 option
  Linux only, ignored on other platforms (but may be specified)
- $klogParseKernelTimeStamp [on/off]
  equivalent to: ParseKernelTimeStamp
- $klogKeepKernelTimeStamp [on/off]
  equivalent to: KeepKernelTimeStamp

[rsyslog.conf overview] [manual index] [rsyslog site]

This documentation is part of the rsyslog project.
Copyright © 2008-2012 by Rainer Gerhards and Adiscon. Released under the GNU GPL version 3 or higher.