netconsole or serial logging in XenServer DomU

Question

I have some problems with stability of Debian guests in my XenServer hosts.

To debug this problem I wanted to use netconsole kernel module, unfortunately, because the Ethernet controller is emulated, it doesn't support polling and in effect netconsole:

[23463.961946] netconsole: local port 6665
[23463.961950] netconsole: local IP 10.10.12.10
[23463.961952] netconsole: interface eth0
[23463.961954] netconsole: remote port 6667
[23463.961956] netconsole: remote IP 10.10.12.1
[23463.961958] netconsole: remote ethernet address ff:ff:ff:ff:ff:ff
[23463.961962] netconsole: eth0 doesn't support polling, aborting.
[23463.961971] netconsole: cleaning up

Are there any alternatives to netconsole not requiring physical access to host? I've got network syslog already configured.

Edit:

How is it possible to log all serial output coming from a particular DomU?

Disk access hangs with `INFO: task jbd2:288 blocked for more than 120 seconds.` — Hubert Kario, Nov 26 '11 at 00:42
jbd2 is a daemon for syncing the journal block device in ext4. A workaround might be using ext3. — Nils, Nov 26 '11 at 21:26
The problem is not limited to `jbd2`, sometimes it's `smbd`, sometimes `slapd`. — Hubert Kario, Nov 28 '11 at 15:27

score 0 · Answer 1 · answered Nov 25 '11 at 14:44

This is a bit of stretch, but just got this idea while on my way home and typing this with my iPhone. Yes, I have no life and I must scream. Anyway...

I wonder if pam_tty_audit module could be used for this. Configure a special user for it, make the user automatically login to some tty, gather the reports about screen events afterwards with aureport.

A desperate attempt, I know, but man gotta try.

score 0 · Answer 2 · answered Nov 26 '11 at 21:23

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Since I did not know what the heck jbd2 is I googled and found this bug (#666828) in the Ubuntu bug database. I was not able to access the associated RedHat bug but this looks like a serious problem that even hits physical machines.

answered Nov 26 '11 at 21:23

Nils

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score 0 · Answer 3 · answered Jan 12 '12 at 08:36

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You may want to run a different domU intended only for serial console to all your other domUs. Then, you can make use of the screen utility to switch from one serial console to a particular domU to another.

answered Jan 12 '12 at 08:36

bintut

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By the way, it is assumed that all domUs are on the same dom0. You also use `minicom` to serial console to the other domUs. – bintut Jan 13 '12 at 00:30

netconsole or serial logging in XenServer DomU

Edit:

3 Answers3