Fwd: [opensuse-virtual] Best Practices / Details for Serial Console debug-level logging when using Xen + systemd ?
---------- Forwarded message ---------- 1. Wondering if you have considered the method described at Freedesktop.org(one of my primary sources of info on systemd) http://freedesktop.org/wiki/Software/systemd/Debugging/ 2. Is this for a special purpose? If not and if you're just setting up a regular maintenance system, have you considered extracting and aggregating logs remotely using IP instead of serial using something like Logstash? Tony -- To unsubscribe, e-mail: opensuse-virtual+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-virtual+owner@opensuse.org
HI Tony,
1. Wondering if you have considered the method described at Freedesktop.org(one of my primary sources of info on systemd) http://freedesktop.org/wiki/Software/systemd/Debugging/
2. Is this for a special purpose? If not and if you're just setting up a regular maintenance system, have you considered extracting and aggregating logs remotely using IP instead of serial using something like Logstash?
This is not about a 'regular maintenance system', but rather a low-level, Xen/Kernel boot debugging process, where _specifically_ serial console logs are requested by the devs, etc. I hadn't considered the systemd debugging process; tbh, I wasn't yet aware of the _early_ debug.shell. This "Shutdown Never Finishes If normal reboot or poweroff never finish even after waiting a few minutes, the above method to create the shutdown log will not help and the log must be obtained using other methods. Two options that are useful for debugging boot problems can be used also for shutdown problems: use a serial console use a debug shell - not only is it available from early boot, it also stays active until late shutdown. " seems like it'd grab the early processes/info. Not at all sure if/how using "a debug shell" works with Xen in the mix. At 'another post', I was instructed by one of the devs that serial console is "expected" to be working first, before debugging kernel-xen, and, in the post above, there's reference to the "Xen console driver", which, I gather is what requires console output? In any case, the Suse kernel-/xen- folks have NOT requested/suggested the output from the systemd-debugging process you've provided reference to (I presume they'd be aware_, but, rather, ONLY have requested serial console log output. If the systemd info *IS* a possibilty that provides a sufficient alternative, AND gets around the fact that I'm currently unable to get a peep out of serial console, I'd be VERY interested to know that. -- To unsubscribe, e-mail: opensuse-virtual+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-virtual+owner@opensuse.org
OK, So, I took a quick peek at what your likely options are (consider I haven't actually tried to troubleshoot early boot issues like you're describing) Specifically in virtualization managed by virt-manager First, The freedesktop article describes being able to point to a Text Console. I haven't yet found out how to configure that option, the default as always is a VNC graphical console and the option to point to a Serial Console is greyed out. In fact, although I tried adding serial outputs to the Guest Config, no matter what type of serial output I chose the output to text console remains greyed out (although seems to recognize the serial connection). But, there are some other interesting serial output options... If you don't need an interactive console, it looks like there is an option to output to file, so you should be able to capture your debug information in a file without actually deploying a getty. HTH, Tony -- To unsubscribe, e-mail: opensuse-virtual+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-virtual+owner@opensuse.org
Hi Tony, On Thu, Jul 4, 2013, at 10:44 AM, Tony Su wrote:
So, I took a quick peek at what your likely options are ... (snip)
Thanks I'm not yet as far along as you clearly are, but have stumbled at the same issues you'd mentioned.
If you don't need an interactive console
I do, as per https://bugzilla.novell.com/show_bug.cgi?id=825510#c6 "... issuing the 'd' debug key from the serial console ought to still work, and should give us insight into what's going on ..." Iiuc, the systemd debug-shell approach doesn't get me there. -- To unsubscribe, e-mail: opensuse-virtual+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-virtual+owner@opensuse.org
On 04.07.13 at 19:55, ar16 <ar16@imapmail.org> wrote: If you don't need an interactive console
I do, as per
https://bugzilla.novell.com/show_bug.cgi?id=825510#c6 "... issuing the 'd' debug key from the serial console ought to still work, and should give us insight into what's going on ..."
So you are _still_ confusing things, and now also confuse other people: There are two possible destinations for input from the serial console: The hypervisor, or Dom0. When requesting debug key output, it is (obviously to me) hypervisor mode that you need to put the system in, either via boot time command line option, or via (pseudo-)hotkey; the default is Dom0 mode. Talking of debug shells is, just like any other option that involves Dom0 in _any_ way, not suitable in situations where Dom0 (likely) doesn't have control of the system anymore (like in your hanging shutdown case). Jan -- To unsubscribe, e-mail: opensuse-virtual+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-virtual+owner@opensuse.org
participants (3)
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ar16 -
Jan Beulich -
Tony Su