[PATCH 35/35] monitor: add option --keep/-K

[Martin Wilck]

On Fri, 2021-01-29 at 12:57 -0800, Sagi Grimberg wrote:
> 
> > > > But I'm not quite following you here, because this option is
> > > > about
> > > > keeping controllers up after the monitor exits. Given that the
> > > > monitor
> > > > would be the instance that receives the AENs and acts upon
> > > > them,
> > > > what's
> > > > the point of keeping them alive after it has terminated?
> > > 
> > > It may run again at some point.
> > > 
> > 
> > If it does, it will recreate discovery controllers for every
> > host_traddr/traddr/trsvcid tuple it finds. "--keep" semantics are
> > only
> > necessary for addresses on which no regular (non-discovery)
> > connection
> > exists.
> 
> Wait, Maybe I'm missing something here, but are you saying that for
> every traddr/trsvcid it finds (both nvm and discovery) it will
> attempt
> to connect a discovery controller?
> 
> If so, this is absolutely wrong.

Currently, it tries to do that on startup, if (and only if) the 
--startup option is given. My expectation was that the connection
attempts would simply fail if there was no discovery subsystem to
connect to. Anyway, it's not the default behavior, and can be dropped
completely if it's so bad that we shouldn't ever attempt to do it.

If the service is started early on during boot, and event-based
discovery works (i.e. we also have the mDNS part in place), this won't
be necessary of course.

Regards
Martin