I spent many, many hours trying to understand why I couldn’t have both “nova console-log” showing me the output of the log, AND have the OpenStack dashboard (eg: horizon) console to work at the same time. Normally, this is done very easily, by passing multiple times the console= parameter to the Linux kernel as follow:
console=tty0 console=ttyS0,115200
But it never worked. Always, it’s the last console= thing that was taken into account by sysvinit (or, shall I say, bootlogd). Spending hours trying to figure out what would be the correct kernel command to pass didn’t help. Then this week-end, by the magic pure chance of being subscribed to the sysvinit bug reports, I have finally found out. We’ve had this bug in Debian for more than 10 years:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=181756
And it has the patch! It just feels so lame that the issue has been pending since 2003, and with a patch since 2006, and nobody even tried to have it enter Debian. I tried the Wheezy patch in the above bug report, and then tadaaaaaa! I finally had both the “nova console-log” (eg: ttyS0) console output, and the interactive tty0 to work on my Debian cloud image. I have produced a fixed version of the sysvinit package for Wheezy, if anyone wants to try it:
http://archive.gplhost.com/debian/pool/juno-backports/main/s/sysvinit/
This doesn’t only affect only the cloud images use case. Let’s say you have a server. If it’s a modern server, probably you have IPMI 2.0 on it. While having access through the integrated KVM over IP may be nice, seeing the boot process through the serial console redirection is often a lot more snappy than the (often VNC based) video output, plus it wouldn’t require Java. Too often, Java a requirement for these nasty IPMI web interface (that’s the case for at least: Dell DRAC, Supermicro IMPI, and HP iLO). Well, it should now be possible to just use ipmitools to debug the server boot process or to go fix stuff in the single user interactive shell, AND keep the “normal” video output! :)
But keeping this fix private doesn’t help much. I would really love to get this fixed within Debian. So I have sent the patch (which needed a very small rebase) in the Git repository of sysvinit (see http://deb.li/3YxUD). I of course tested it in Sid too. Though I tested only under a Xen virtual machine, I see no reason why it would work there and not elsewhere. That being said, I would welcome more testing, given the high profile of sysvinit (everyone uses/needs it, and I wouldn’t like to carry alone the unhappiness of having no boot log). Please do test it from the sysvinit git, before it’s even uploaded to Sid. Also, these days, sysvinit gets often uploaded to Experimental first. It will probably also be the case for version 2.88dsf-56.
If it works well and nobody complains about the patch, maybe it’d be worth adding it to Wheezy as well (though that decision is of course left to the release team once the fix reaches Jessie).