[libvirt] [PATCH] Leave all child processes running when stopping systemd service

[Daniel P. Berrange]

On Thu, Mar 22, 2012 at 02:27:59PM +0000, Mark McLoughlin wrote:
> On Thu, 2012-03-22 at 14:22 +0000, Daniel P. Berrange wrote:
> > On Thu, Mar 22, 2012 at 02:10:30PM +0000, Mark McLoughlin wrote:
> > > On Thu, 2012-03-22 at 14:03 +0000, Daniel P. Berrange wrote:
> > > > From: "Daniel P. Berrange" <berrange at redhat.com>
> > > > 
> > > > Currently the libvirt.service unit file for systemd does not
> > > > specify any kill mode. So systemd kills off every process
> > > > inside its cgroup. ie all dnsmasq processes, all virtual
> > > > machines. This obviously not what we want. Set KillMode=process
> > > > so that it only kills the top level process of libvirtd
> > > > 
> > > > * daemon/libvirtd.service.in: Add KillMode=process
> > > 
> > > I was still looking through this. Try doing:
> > > 
> > >   $> systemctl restart libvirtd.service
> > > 
> > > It's killing the existing processes in the cgroup when starting the
> > > service. From poking at an strace, this looks like the code that's doing
> > > it:
> > > 
> > >   http://cgit.freedesktop.org/systemd/systemd/tree/src/service.c?id=75c8e3cf#n2093
> > 
> > It didn't kill guests/dnsmasq in my testing.  Are you sure you did
> > a 'systemctl daemon-reload' after adding the KillMode flag to the
> > unit file ?
> 
> Yep:
> 
> [markmc at zig ~]$ sudo systemctl show libvirtd.service | grep KillMode
> KillMode=process
> [markmc at zig ~]$ systemd-cgls /system/libvirtd.service
> /system/libvirtd.service:
> ├ 12660 /usr/sbin/libvirtd
> ├ 20598 /usr/bin/qemu-kvm -S -M pc-0.15 -enable-kvm -m 2048 -smp 1,sockets=1,cores=1,threads=1 -name instance-00000021 -uuid 39e9ec0e-2...
> └ 20665 /sbin/dnsmasq --strict-order --bind-interfaces --pid-file=/var/run/libvirt/network/default.pid --conf-file= --except-interface ...
> [markmc at zig ~]$ sudo systemctl restart libvirtd.service
> [markmc at zig ~]$ systemd-cgls /system/libvirtd.service
> /system/libvirtd.service:
> └ 20742 /usr/sbin/libvirtd

Hmm, that's not the behaviour I see, once I ran 'daemon-reload'.

# systemd-cgls /system/libvirtd.service
/system/libvirtd.service:
├ 19607 /usr/sbin/dnsmasq --strict-order --bind-interfaces --pid-file=/var/run/libvirt/network/default.pid --conf-file= --ex...
├ 19809 /usr/libexec/qemu-kvm -S -M pc-0.13 -enable-kvm -m 215 -smp 4,sockets=4,cores=1,threads=1 -name vm1 -uuid c7a3edbd-e...
└ 19849 /usr/sbin/libvirtd

[root at t500wlan system]# systemctl stop libvirtd.service
[root at t500wlan system]# systemd-cgls /system/libvirtd.service
/system/libvirtd.service:
├ 19607 /usr/sbin/dnsmasq --strict-order --bind-interfaces --pid-file=/var/run/libvirt/network/default.pid --conf-file= --ex...
└ 19809 /usr/libexec/qemu-kvm -S -M pc-0.13 -enable-kvm -m 215 -smp 4,sockets=4,cores=1,threads=1 -name vm1 -uuid c7a3edbd-e...

[root at t500wlan system]# systemctl start libvirtd.service
[root at t500wlan system]# systemd-cgls /system/libvirtd.service
/system/libvirtd.service:
├ 19607 /usr/sbin/dnsmasq --strict-order --bind-interfaces --pid-file=/var/run/libvirt/network/default.pid --conf-file= --ex...
├ 19809 /usr/libexec/qemu-kvm -S -M pc-0.13 -enable-kvm -m 215 -smp 4,sockets=4,cores=1,threads=1 -name vm1 -uuid c7a3edbd-e...
└ 26391 /usr/sbin/libvirtd


Daniel
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