[openstack-dev] [Neutron][L3] Orphaned process cleanup

Sean M. Collins sean at coreitpro.com
Wed Jan 27 21:52:19 UTC 2016

On Wed, Jan 27, 2016 at 04:24:00PM EST, Assaf Muller wrote:
> On Wed, Jan 27, 2016 at 4:10 PM, Sean M. Collins <sean at coreitpro.com> wrote:
> > Hi,
> >
> > I started poking a bit at https://bugs.launchpad.net/devstack/+bug/1535661
> >
> > We have radvd processes that the l3 agent launches, and if the l3 agent
> > is terminated these radvd processes continue to run. I think we should
> > probably terminate them when the l3 agent is terminated, like if we are
> > in DevStack and doing an unstack.sh[1]. There's a fix on the DevStack
> > side but I'm waffling a bit on if it's the right thing to do or not[2].
> >
> > The only concern I have is if there are situations where the l3 agent
> > terminates, but we don't want data plane disruption. For example, if
> > something goes wrong and the L3 agent dies, if the OS will be sending a
> > SIGABRT (which my WIP patch doesn't catch[3] and radvd would continue to run) or if a
> > SIGTERM is issued, or worse, an OOM event occurs (I think thats a
> > SIGTERM too?) and you get an outage.
> RDO systemd init script for the L3 agent will send a signal 15 when
> 'systemctl restart neutron-l3-agent' is executed. I assume
> Debian/Ubuntu do the same. It is imperative that agent restarts do not
> cause data plane interruption. This has been the case for the L3 agent

But wouldn't it really be wiser to use SIGHUP to communicate the intent
to restart a process? 

Sean M. Collins

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