Re: [Xen-devel] Test Xen 4.8 RC4 not stable 27.10.16

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Fri, Oct 28, 2016 at 12:04:29PM -0400, Boris Ostrovsky wrote:
> On 10/28/2016 11:30 AM, Wei Liu wrote:
> > On Fri, Oct 28, 2016 at 04:01:54PM +0100, Juergen Schinker wrote:
> >>
> >> ----- On 28 Oct, 2016, at 13:07, Boris Ostrovsky 
> >> boris.ostrovsky@xxxxxxxxxx wrote:
> >>
> >>> I believe at least on some distros /var/run should be soft-linked to
> >>> /run, otherwise whoever cleans up those directories (the command name
> >>> escapes me right now) will only remove files from /run and leave
> >>> /var/run (and therefore /var/run/xen/xenstored.pid) untouched.
> >>>
> >>> And because xencommons checks for existence of this this file before
> >>> starting xenstored the latter never starts.
> >>>
> >>> -boris
> >> root@xen:~# ls -la /var/run/xen/xenstored.pid 
> >> -rw-r----- 1 root root 6 Oct 28 15:15 /var/run/xen/xenstored.pid
> >>
> >>   
> >>    33 ?        00:00:00 xenwatch
> >>    34 ?        00:00:00 xenbus
> >>    45 ?        00:00:00 xenbus_frontend
> >>   785 ?        00:00:00 xen_pciback_wor
> >>  1137 ?        00:00:00 xenwatchdogd
> >>  1169 ?        00:00:00 xen-init-dom0
> >>  1175 ?        00:00:00 xenconsoled

And this ^ 

xenconsoled requires xenstored.service, so if xenstored is not available
xenconsoled wouldn't be started, I think.

xen-init-dom0 as well.

> >>
> >> Thats exactly what I'm sayin , maybe we need a more intelligent check to 
> >> see if xenstored is running
> >>
> >> not just a simple pid check
> >>
> > But ... the pid check is the usual way of checking if a daemon is
> > active.
> >
> > I think a bit work is required to work out why xenstored.pid stays
> > across reboot -- it is not supposed to work like that on a FHS compliant
> > system.
> 
> I remember now: it's systemd-tmpfiles that creates and cleans up those
> files. I think the way it works is it checks
> /usr/lib/tmpfiles.d/var.conf for the rules. On my fedora24:
> 
> L /var/run - - - - ../run
> 
> Which IIUIC means that /var/run should be linked to ../run (i.e. /run)
> during boot. Or something along these lines. Perhaps because when we
> shut down xenstored.pid is still there and so the link cannot be made.

It's the same on my Debian Jessie box, but it works just fine, FWIW.

Wei.

> 
> 
> -boris
> 
> >
> > And how do other daemons work on your test host, presumably they will
> > see stale pid files as well.  Are there any other pid files under
> > /var/run? If so, do the corresponding daemon run properly?
> >
> > Wei.
> >
> >> J
> 
> 

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