Editing Remote console setup

In case you are experiencing a kernel crash (oops) and have already [[Troubleshooting:Hardware|checked your hardware]], you should report what kernel says to the console to [http://bugzilla.openvz.org/ Bugzilla]. Sometimes kernel crashes so badly that syslogd is not working and what kernel says it never written to a file. If this is the case, you have to catch what kernel says. There are several ways possible.

== Manual/Photo ==
If kernel backtrace is not long enough there are chances that it can fit into a single screen. In that case, you can just make a photo of the kernel crash screen and attach it to the bug report. If you do not have a camera, you still can carefully write down (using a piece of paper and a pen, that is) what you see on the screen, and later type it into the bug report.

== Serial console ==
FIXME

== Netconsole ==

=== Kernel recompilation ===
If you use binary kernel from openvz.org, it already has netconsole module compiled in, so just skip to next section.

If you build the kernel yourself, you might need to check if netconsole is compiled. To that effect, change to your kernel source directory and grep your kernel <tt>.config</tt> for NETCONSOLE:
<pre>
# cd /usr/src/openvz/linux-2.6.16
# grep NETCONSOLE .config
</pre>

If you see nothing or "# CONFIG_NETCONSOLE is not set" you need to recompile the kernel.

Edit your kernel configuration file <tt>.config</tt> with a text editor (<tt>nano .config</tt> or <tt>vi .config</tt>). Set netconsole to Y or M (depending on whether you want it as a module or built into the kernel; I have compiled it as a module):

<pre>CONFIG_NETCONSOLE=m</pre>

Save the file, then recompile the kernel:

<pre>
# make bzImage && make modules && make modules_install
</pre>
Update your bootloader for the new updated kernel. In my case I use LILO so I just type lilo at the prompt.

Reboot into new kernel.

=== Setting up OpenVZ side ===

Next you want your netconsole to send the request to somewhere. Load netconsole module, specifying the remote server parameters:

<pre># modprobe netconsole netconsole=4444@10.0.2.1/eth0,6666@10.0.2.2/00:05:5D:34:11:AF</pre>

This will load the module with your settings. Replace your local IP address with where <tt>10.0.2.1</tt> is, <tt>eth0</tt> with your network interface card device, <tt>6666</tt> with the remote netconsole port (UDP), and <tt>10.0.2.2</tt> with your remote netconsole server IP. Also add in the mac address of your remote netconsole server, which in my case was 00:05:5D:34:11:AF. You can get the MAC address using arp utility:

<pre>
# ping -c 1 10.0.2.2
# /sbin/arp -i 10.0.2.2
? (10.0.2.2) at 00:05:5D:34:11:AF [ether] on eth2
</pre>

Netconsole documentation is available from <tt>Documentation/networking/netconsole.txt</tt> file under your kernel source directory.

=== Setting up remote side === 

Setup netcat on your console server to listen on port 6666 UDP:

<pre>netcat -u -l -p6666</pre>

When your kernel prints something on the console, the text will be also captured on this netconsole server.