[lxc-users] Trying out migration, getting "error: checkpoint failed"

[Tycho Andersen]

Hi Giles,

On Tue, May 05, 2015 at 05:10:56PM +0100, Giles Thomas wrote:
> Hi Tycho,
> 
> On 05/05/15 16:50, Tycho Andersen wrote:
> >Can you check the lxd stderr by chance (probably lives in /var/log
> >somewhere depending on what init system you're using)? I suspect that
> >liblxc is rejecting dumping the container in its internal predump checks,
> >but the above log doesn't say way unfortunately. Sorry for all the
> >confusion, the logging stuff here is still a bit of a mess, although a bit
> >better on the current lxd master.
> 
> Oddly, there didn't appear to be one; "find /var/log -name \*lxd\*" just
> found "/var/log/lxd".  Nothing relevant-looking in "/var/log/upstart/" apart
> from "lxc-net.log", which has an "Address already in use" error:
> 
>     dnsmasq: failed to create listening socket for 10.0.3.1: Address already
> in use
>     Failed to setup lxc-net.
> 
> Doubly-oddly, there's a "/etc/init/lxd.conf" *and* a "/etc/init.d/lxd",
> which confuses me a little.  Does that not mean that both init and upstart
> will try to start it?  (My knowledge of the workings of init systems in not
> as in-depth as I would like.) Should I remove one of them then change the
> remaining one to write stdout/err somewhere sensible?

You could, but it may be easier to just stop the lxd service and run
it manually so that it writes stderr to the terminal you're using.

Looking at the code path, it looks like there are a few (really
unlikely) ways it could fail without writing anything to the log (such
as OOM or not being able to make a temporary directory, but it's root
so as long as you have enough disk/ram it /should/ die with some error
message). If you can't find anything, it may be worth building a
liblxc from source and trying to debug things that way.

> I can also see that there are still init and upstart scripts for lxcfs,
> which is a bit messy -- the "apt-get remove lxcfs" should presumably have
> deleted them -- but they depend on "/usr/bin/lxcfs", which definitely
> doesn't exist, so I guess that's not the problem.

`remove` doesn't always remove config files, `purge` is supposed to
though.

Tycho

> 
> All the best,
> 
> Giles
> 
> -- 
> Giles Thomas <giles at pythonanywhere.com>
> 
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