Xen users - May 2006 - FIX: was Re: "Exception starting xend ((2, ''No such file or directory''))" - what file?

Poor form to reply to myself, I know.

Looks like Ubuntu Dapper clears out /var/run on reboot, so
I needed to add:

  mkdir -p /var/run/xenstored

to the top of the initscript to ensure dom0 comes up.

IMO it''s usual to assume /var/run is transient, so it might be
an idea for xenstored to ensure it''s created before trying to use it.

(We don''t have a /var/lock/subsys either, but that looks less fatal :)
)

On 11/05/06, Dick Davies <rasputnik@gmail.com>
wrote:
> Hi all, I can''t get xend to start and could do with some help.
>
> this is the stock 30.2 release. it was working fine on ubuntu breezy,
> and since I''ve updated to dapper it''s boned...
>
> The odd thing is, if I run the installer, I can start xend ok. but when
> I reboot it''s broken again.
>
> I''m guessing a directory is being deleted by ubuntu at reboot time
-
> is there an easy way to figure out what exactly xend is trying to open?
>
> [2006-05-11 11:17:21 xend] INFO (SrvDaemon:278) Xend Daemon started
> [2006-05-11 11:17:21 xend] INFO (SrvDaemon:282) Xend changeset: Thu
> Apr 13 15:18:37 2006 +0100 9617:5802713c159b.
> [2006-05-11 11:17:21 xend] ERROR (SrvDaemon:292) Exception starting
> xend ((2, ''No such file or directory''))
> Traceback (most recent call last):
>   File "/usr/lib/python/xen/xend/server/SrvDaemon.py", line 286,
in run
>     servers = SrvServer.create()
>   File "/usr/lib/python/xen/xend/server/SrvServer.py", line 108,
in create
>     root.putChild(''xend'', SrvRoot())
>   File "/usr/lib/python/xen/xend/server/SrvRoot.py", line 40, in
__init__
>     self.get(name)
>   File "/usr/lib/python/xen/web/SrvDir.py", line 82, in get
>     val = val.getobj()
>   File "/usr/lib/python/xen/web/SrvDir.py", line 52, in getobj
>     self.obj = klassobj()
>   File "/usr/lib/python/xen/xend/server/SrvDomainDir.py", line
39, in __init__
>     self.xd = XendDomain.instance()
>   File "/usr/lib/python/xen/xend/XendDomain.py", line 582, in
instance
>     inst.init()
>   File "/usr/lib/python/xen/xend/XendDomain.py", line 70, in init
>     xstransact.Mkdir(VMROOT)
>   File "/usr/lib/python/xen/xend/xenstore/xstransact.py", line
317, in Mkdir
>     complete(path, lambda t: t.mkdir(*args))
>   File "/usr/lib/python/xen/xend/xenstore/xstransact.py", line
323, in complete
>     t = xstransact(path)
>   File "/usr/lib/python/xen/xend/xenstore/xstransact.py", line
20, in __init__
>     self.transaction = xshandle().transaction_start()
>   File "/usr/lib/python/xen/xend/xenstore/xsutil.py", line 18, in
xshandle
>     xs_handle = xen.lowlevel.xs.xs()
> RuntimeError: (2, ''No such file or directory'')
> (END)
>
> --
> Rasputin :: Jack of All Trades - Master of Nuns
> http://number9.hellooperator.net/
>

-- 
Rasputin :: Jack of All Trades - Master of Nuns
http://number9.hellooperator.net/

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Dick Davies wrote:
> Looks like Ubuntu Dapper clears out /var/run on reboot, so
> I needed to add:
>
>   mkdir -p /var/run/xenstored
>
> to the top of the initscript to ensure dom0 comes up.
Yesterday I had the same problem as you ;-)
> IMO it''s usual to assume /var/run is transient, so it might be
> an idea for xenstored to ensure it''s created before trying to use
it.
Yes, that would be a good idea. This problem appeared here with
the directory /var/run/xend, too. This directory should also be
created by start of xend, e.g. the init script or xend itself.
> On 11/05/06, Dick Davies <rasputnik@gmail.com> wrote:
> [...]
>> xend ((2, ''No such file or directory''))
Why do the xen tools (like xm) display such boring error messages, e.g.
omitting the name of the file? Yesterday I searched a lot of time with
strace to find the reason why my domU did not start...

Each poor Unix/Linux tool displays missing file names using perror(3),
why not xm?

Regards,

Frank

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On 11/05/06, Frank Meyer <frank@fli4l.de> wrote:
> Yesterday I had the same problem as you ;-)
>
> > IMO it''s usual to assume /var/run is transient, so it might
be
> > an idea for xenstored to ensure it''s created before trying to
use it.
>
> Yes, that would be a good idea. This problem appeared here with
> the directory /var/run/xend, too. This directory should also be
> created by start of xend, e.g. the init script or xend itself.
Someone on ubuntu-users mentioned that, but
...(removes it and reboots to check)...
yeah, /var/run/xend *is* being created properly, with xen 3.0.2.

xenstored just needs  a similar fix.
> >> xend ((2, ''No such file or directory''))
> Why do the xen tools (like xm) display such boring error messages, e.g.
> omitting the name of the file? Yesterday I searched a lot of time with
> strace to find the reason why my domU did not start...
>
> Each poor Unix/Linux tool displays missing file names using perror(3),
> why not xm?
/usr/libpython/xen isn''t much fun to trawl through either ( especially
if
you''re a ruby programmer :) )

There is an environment variable, XENSTORED_TRACE, that /usr/sbin/xend
suggests should do something, but that just created me an empty logfile.

-- 
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http://number9.hellooperator.net/

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On Thu, May 11, 2006 at 03:23:15PM +0100, Dick Davies
wrote:
> xenstored just needs  a similar fix.
done :)

-- 
Vincent Hanquez

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Dick Davies wrote:
> Someone on ubuntu-users mentioned that, but
> ...(removes it and reboots to check)...
> yeah, /var/run/xend *is* being created properly, with xen 3.0.2.
On my xen-3.0.2 system /var/run/xend has *not* being created by xend:

eis # rm -r /var/run/xenstored /var/run/xend
eis # /etc/init.d/xend start
eis # ps -ef | grep xend
root      2727     1  0 17:30 ?        00:00:00 python /usr/sbin/xend start
root      2729  2727  0 17:30 ?        00:00:00 python /usr/sbin/xend start
root      2731  2729  0 17:30 ?        00:00:00 python /usr/sbin/xend start
root      2732  2731  0 17:30 ?        00:00:00 python /usr/sbin/xend start
root      2738  2676  0 17:30 pts/0    00:00:00 grep xend
eis # xm create -c xmeisfair
Using config file "/etc/xen/xmeisfair".
Error: (2, ''No such file or directory'')            <-----
here it is!
eis # ls -l /var/run/xenstored /var/run/xend
ls: /var/run/xenstored: No such file or directory
ls: /var/run/xend: No such file or directory

Sorry ;-),

Frank

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On 11/05/06, Frank Meyer <frank@fli4l.de> wrote:
> Dick Davies wrote:
>
> > Someone on ubuntu-users mentioned that, but
> > ...(removes it and reboots to check)...
> > yeah, /var/run/xend *is* being created properly, with xen 3.0.2.
>
> On my xen-3.0.2 system /var/run/xend has *not* being created by xend:
>
> eis # rm -r /var/run/xenstored /var/run/xend
> eis # /etc/init.d/xend start
> eis # ps -ef | grep xend
> root      2727     1  0 17:30 ?        00:00:00 python /usr/sbin/xend start
> root      2729  2727  0 17:30 ?        00:00:00 python /usr/sbin/xend start
> root      2731  2729  0 17:30 ?        00:00:00 python /usr/sbin/xend start
> root      2732  2731  0 17:30 ?        00:00:00 python /usr/sbin/xend start
> root      2738  2676  0 17:30 pts/0    00:00:00 grep xend
> eis # xm create -c xmeisfair
> Using config file "/etc/xen/xmeisfair".
> Error: (2, ''No such file or directory'')           
<----- here it is!
> eis # ls -l /var/run/xenstored /var/run/xend
> ls: /var/run/xenstored: No such file or directory

Got t. If you make the xenstored directory, then xend can do its own:


planb:~/ $ rm -r /var/run/xend* /var/run/xenstore*
planb:~/ $ /etc/init.d/xend start
planb:~/ $ ls -ld /var/run/xend /var/run/xenstored
ls: /var/run/xend: No such file or directory
ls: /var/run/xenstored: No such file or directory
planb:~/ $ /etc/init.d/xend stop
planb:~/ $ vi /etc/init.d/xend
# add a line at the top to ''mkdir -p /var/run/xenstored''
planb:~/ $ /etc/init.d/xend start
planb:~/ $ ls -ld /var/run/xend /var/run/xenstored
drwx------ 2 root root 60 2006-05-11 15:53 /var/run/xend
drwxr-xr-x 2 root root 80 2006-05-11 15:53 /var/run/xenstored

Probably worth doing it in xen itself, so you don''t pick up a  screwy
umask
like I just did (755 probably not the best permissions to put on the xenstored/
directory...)


-- 
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http://number9.hellooperator.net/

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On Thu, May 11, 2006 at 03:57:20PM +0100, Dick Davies
wrote:
> Probably worth doing it in xen itself, so you don''t pick up a 
screwy umask
> like I just did (755 probably not the best permissions to put on the 
> xenstored/
> directory...)
0755 is fine. both sockets are only open-able by root anyway.

-- 
Vincent Hanquez

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