Re: [libvirt] [RFC PATCH] lxc: don't return error on GetInfo when cgroups not yet set up
Quoting Daniel P. Berrange (berrange(a)redhat.com):
On Wed, Sep 28, 2011 at 02:14:52PM -0500, Serge E. Hallyn wrote:
> Nova (openstack) calls libvirt to create a container, then
> periodically checks using GetInfo to see whether the container
> is up. If it does this too quickly, then libvirt returns an
> error, which in libvirt.py causes an exception to be raised,
> the same type as if the container was bad.
lxcDomainGetInfo(), holds a mutex on 'dom' for the duration of
its execution. It checks for virDomainObjIsActive() before
trying to use the cgroups.
Yes, it does, but
lxcDomainStart(), holds the mutex on 'dom' for the duration
of
its execution, and does not return until the container is running
and cgroups are present.
No. It calls the lxc_controller with --background. The controller
main task in turn exits before the cgroups have been set up. There
is the race.
-serge