RE: Help booting Xen under RHEL6 beta2

[Dan Magenheimer <dan.magenheimer@oracle.com>]

> I'm in the process of doing a fresh build which will
> take awhile.

Backing out to xen-4.0.1-rc3 did not help, though short
of reinstalling the entire system from scratch, I'm not
sure how to ensure I've backed _everything_ out to rc3...
there's too many flying parts.

> > So I rebooted (with xend disabled), manually started xenstored,
> > and ensured xenstored is indeed running with ps -ef.
> > Then I tried "xenstore-ls" and all I get is:
> >
> > tool = ""
> >  xenstored = ""
> > local = ""
> >
> > I tried this on a EL5-based distro running a 2.6.18.8-xen
> > dom0 (with xend disabled on boot) and xenstore-ls gives
> > me a long list of dom0 related registry entries.
> 
> Those dom0 registry entries would be written by xend. If you just run
> xenstored, you'd expect the database to be pretty empty. Looks like
> xenstored is running okay.

I had forgotten that the xenstored data is persistent across
boot, so I removed /var/lib/xenstored/tdb on the working machine
and rebooted.  The behavior is still different between the
two systems.  This may or may not be relevant or provide a
clue to someone who knows far more about xenstored and xend
than I do.  It appears to me that dom0 is "waiting" to connect
to xenstored on the good system, but not on the bad system.
Any chance this might be related to the renaming of evtchn
(to xen_evtchn or xen-evtchn or whatever it is)?  How might
I check that?

# GOOD system, xen-4.0-testing c/s 21209, 2.6.18.8-xen dom0, EL5 distro

# ls /var/lib/xenstored/tdb
ls: /var/lib/xenstored/tdb: No such file or directory
# xenstore-ls
xenstore-ls: xs_directory (/): No such device
# xenstored
# xenstore-ls
tool = ""
 xenstored = ""
local = ""
 domain = ""
  0 = ""
   device = ""
    suspend = ""
     event-channel = "39"
# /usr/lib/xen/bin/lsevtchn | grep 39
 39: VCPU 0: Interdomain (Waiting connection) - Remote Domain 0
# # NOTE, xend not started yet

#############################################
# BAD system, xen-4.0-testing c/s 21263, 2.6.32.16 pvops dom0, RHEL6b2 distro

# ls /var/lib/xenstored/tdb
ls: cannot access /var/lib/xenstored/tdb: No such file or directory
# xenstore-ls  ## HANGS until xenstored in another window!!
# xenstored
# xenstore-ls
tool = ""
 xenstored = ""
# ls /usr/lib/xen/bin/lsevtchn
ls: cannot access /usr/lib/xen/bin/lsevtchn: No such file or directory
# cd src/xen/xen-4.0-testing.hg
# tools/xcutils/  adfljad;khgalkjgdhl
11: VCPU 0: Interdomain (Waiting connection) - Remote Domain 0, Port 28
28: VCPU 0: Interdomain (Waiting connection) - Remote Domain 0, Port 11
# # attempting to start xend prints a handful of dots, no errors,
# # but /var/log/xen/xend.log shows the "Connection refused" failure
# # and xend hasn't started

> Perhaps xend is trying to connect to xenstored in
> a different way to xenstore-ls. There are two different ways to connect
> --
> via a Unix domains socket /var/run/xenstored/socket; or via a kernel
> device /proc/xen/xenbus.

Could be, though I haven't intentionally changed anything other
than switching to the RHEL6b2 distro and 64-bit pvops dom0.

Dan