[dm-devel] [Question] multipathd.service start failed when /var/run isn't mount

[Benjamin Marzinski]

On Fri, Jul 23, 2021 at 02:27:58PM +0800, lixiaokeng wrote:
> 
> 
> On 2021/7/23 5:42, Benjamin Marzinski wrote:
> > On Thu, Jul 22, 2021 at 10:51:22AM +0800, lixiaokeng wrote:
> >> When we enable multipathd.service with systemctl and reboot,
> >> multipathd doesn't start and log "failed to create pidfile".
> >>
> >> The reason is following:
> >>
> >> The RUN is /var/run in multipath-tools. When we start linux, we
> >> mount a disk to /var. So if multipathd.service start before mount,
> >> it will fail to activate.(If mount firstly, multipathd will start
> >> successfully)
> >>
> >> The RUN is defined in Makefile.inc:
> >>
> >> ifndef RUN
> >>         ifeq ($(shell test -L /var/run -o ! -d /var/run && echo 1),1)
> >>                 RUN=run
> >>         else
> >>                 RUN=var/run
> >>         endif
> >> endif
> >>
> >> Can it always be defined as run?
> > 
> > I believe all modern distributions make /var/run a symlink to /run.
> > However, if that's the case, then I don't understand why you are running
> > into this issue at all, since multipath should be using /run. What
> > multipath packages are you using?
> Yes, there is a symlink to /run in /var. But it is in the disk (such as
> sdb) mounted on /var actually. When reboot, systemd start multipathd
> service firstly then mount sdb to /var. In this way, the multipath
> service will not start.
> 
> After sdb mounted to /var, we can start multipathd service successfully.

But when the binaries were compiled, if /var/run existed and was a
symlink in your build environment, then RUN should equal "run", and
multipath should should be using /run instead of /var/run, right?

This is why I asked what multipath packages are you using.

-Ben
 
> > 
> > -Ben
> > 
> >>
> >> Regards,
> >> Lixiaokeng
> > 
> > .
> >