Re: Issue on netconsole vs. Linux kernel oops

From: linux-os
Date: Thu Dec 16 2004 - 14:21:53 EST

On Thu, 16 Dec 2004, Matt Mackall wrote:

On Thu, Dec 16, 2004 at 10:48:27AM -0800, Park Lee wrote:
I'd like to use netconsole to send local Linux
kernel's final messages (i.e. oops) to remote machine
when the kernel crashes.
Now I can successfully use a built-in netconsole to
send some loacl kernel messages to the remote machine.
(the parameter I send to local kernel on kernel
command line is
"netconsole=@xxxxxxxxxxx/,514@xxxxxxxxxxx/", I run
syslogd in remote machine). For example, When the
local kernel is booting, it will send a message
" audit(1103247021.091:0): initialized" to
remote machine through netconsole, and the syslogd on
remote machine will write the message to
/var/log/messages on remote machine.
What CONFUSE me most is that when the kernel
crashes, there is NO message (oops) about the crash
being wrote down by syslogd on remote machine to
remote /var/log/messages file at all!!
But in the mean time, We can see the outputs of
tcpdump on the remote machine, they are some thing
like the following:

01:36:56.692877 IP > UDP, length 48
01:36:56.692930 IP > UDP, length 29
01:36:56.692982 IP > UDP, length 15
01:36:56.693034 IP > UDP, length 9
01:36:56.693086 IP > UDP, length 16
01:36:56.693121 IP > UDP, length 16
... ...

From these messages, we can see that the netconsole
actually have sent the final messages (oops) to remote
machine when the local kernel crashed. But there are
no corresponding messages recorded by syslogd on
remote machine to /var/log/messages.

From your description, it sounds like syslogd is at fault. Try using
netcat on the remote machine.

Mathematics is the supreme nostalgia of our time.

Depends upon the vendor of your installation, but some require
loghost to be defined in /etc/hosts as the same as localhost and
/etc/nsswitch.conf configured to actually look at that.

Dick Johnson
Penguin : Linux version 2.6.9 on an i686 machine (5537.79 BogoMips).
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