Please ignore this patch, I will post v2 later. Thanks.
在 2020年10月29日 10:20, Lianbo Jiang 写道:
Let's remove some redundant descriptions in the usage
documentation of the logger, and make it clear.
Signed-off-by: Lianbo Jiang <lijiang(a)redhat.com>
kexec-kdump-howto.txt | 65 ++++++++++++++++++++++++-------------------
1 file changed, 37 insertions(+), 28 deletions(-)
diff --git a/kexec-kdump-howto.txt b/kexec-kdump-howto.txt
index 5f57a8428e4f..d2dba492ed60 100644
@@ -888,35 +888,44 @@ Debugging Tips
- Using the logger to output kdump log messages
- Currently, kdump messages are printed with the 'echo' command or redirect
- to console, and which does not support to output kdump messages according
- to the log level.
- That is not convenient to debug kdump issues, we usually need to capture
- additional debugging information via the modification of the options or the
- scripts like kdumpctl, mkdumprd, etc. Because there is no complete debugging
- messages, which could waste valuable time.
- To cope with this challenging, we introduce the logger to output the kdump
- messages according to the log level, and provide a chance to save logs to
- the journald if the journald service is available, and then dump all logs
- to a file, otherwise dump the logs with the dmesg to a file.
- Logging is controlled by following global variables:
- - @var kdump_stdloglvl - logging level to standard error (console output)
- - @var kdump_sysloglvl - logging level to syslog (by logger command)
- - @var kdump_kmsgloglvl - logging level to /dev/kmsg (only for boot-time)
- If any of the variables is not set, this function set it to default:
- - @var kdump_stdloglvl=4 (info)
- - @var kdump_sysloglvl=4 (info)
- - @var kdump_kmsgloglvl=0 (no logging)
+ You can configure the kdump log level in the /etc/sysconfig/kdump.
+ For example:
+ The above configurations indicate that kdump messages will be printed to the
+ console and journald if the journald service is enabled, and the log level is
+ set to 4(info). This is also the current default log level.
Logging levels: fatal(1),error(2),warn(3),info(4),debug(5),trace(6)
- We can easily configure the above variables in the /etc/sysconfig/kdump. For
+ The FATAL level designates very severe error events that will presumably lead
+ the application to abort.
- The above configurations indicate that kdump messages will be printed to the
- console and journald if the journald service is enabled.
+ The ERROR level designates error events that might still allow the application
+ to continue running.
+ The WARN level designates potentially harmful situations.
+ The INFO level designates informational messages that highlight the progress
+ of the application at coarse-grained level.
+ The DEBUG level designates fine-grained informational events that are most
+ useful to debug an application.
+ The TRACE level designates finer-grained informational events than the DEBUG.
+ Currently, the logger works in both the first kernel(kdump service debugging)
+ and the second kernel.
+ In the first kernel, you can find the historical logs in the /var/log/messages
+ or use the journalctl command to check kdump service debugging information. In
+ addition, the 'kexec -d' debugging messages are also saved to
+ in the first kernel.
+ In the second kernel, put the kexec-dmesg.log to a same directory with the
+ vmcore, the log file includes the debugging messages like dmesg and journald
+ For more details, please refer to the /etc/sysconfig/kdump.