[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]

Re: [libvirt] Destroying a suspended LXC domain



Quoting Daniel P. Berrange (berrange redhat com):
> On Fri, Feb 14, 2014 at 11:14:39AM +0100, Richard Weinberger wrote:
> > Hi!
> > 
> > If we suspend a LXC domain libvirt freezes all tasks in the cgroup using the process freezer.
> > Upon destroy libvirt tries to kill all tasks using SIGTERM and later SIGKILL, but as they are frozen
> > the tasks are unkillable.
> > This seems to confuse libvirt, all tasks remain but libvirt forgets the domain.
> > 
> > Here a small example:
> > ---cut---
> > lxc-host1:/etc # /opt/libvirt-dev/bin/virsh domstate my3rdcontainer
> > paused
> > 
> > lxc-host1:/etc # /opt/libvirt-dev/bin/virsh destroy my3rdcontainer
> > error: Failed to destroy domain my3rdcontainer
> > error: internal error: Some processes refused to die
> > 
> > lxc-host1:/etc # ps fax
> > ...
> >  2118 ?        Dsl    0:00 /opt/libvirt-dev/lib/libvirt_lxc --name my3rdcontainer --console 19 --security=none --handshake 22 --backgr
> >  2128 ?        Ds     0:00  \_ /sbin/init
> >  2152 ?        Ds     0:00      \_ /usr/lib/systemd/systemd-journald
> >  2171 ?        Ds     0:00      \_ /bin/dbus-daemon --system --address=systemd: --nofork --nopidfile --systemd-activation
> >  2174 ?        Ds     0:00      \_ /usr/lib/systemd/systemd-logind
> >  2189 ?        Dsl    0:00      \_ /usr/sbin/rsyslogd -n
> >  2778 ?        Ds     0:00      \_ /usr/sbin/cron -n
> >  2782 pts/0    Ds+    0:00      \_ /sbin/agetty --noclear -s console 115200 38400 9600
> >  2786 ?        Ds     0:00      \_ /usr/sbin/sshd -D
> > ...
> > ---cut---
> > 
> > I can think of three options to deal with that.
> > 
> > a) Refuse to destroy a suspended LXC domain
> > 
> > b) Implicitly resume it upon destroy
> > 
> > c) Send a SIGKILL to each task and then thaw all tasks using the process freezer.
> > If the task is woken up the it sees immediately the pending SIGKILL and dies.
> > 
> > I'd vote for c) because I want to destroy a LXC domain without resuming it.
> > I.e. I want to kill it to avoid any further IO from the already suspended domain.
> 
> Yes, I think c) is the only reasonable option here. Allowing processes
> any window where they can continue executing is not ok.

( For the record that's what lxc does as well - +1 )


[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]