Hi,
we have the problem that our xen configuration settings are not correctly
evaluated when creating a xen guests.
When creating domains with "xm create domainname" the system sometimes has all
configuration parameters out of the config files, but sometimes not.
We did some tests and saw that the parameters are only certainly used if we specify them
via the commandline like "xm create domainname parameter=value,...".
If the parameters are only specified in the configuration files in /etc/xen/ they are
parsed and used "sometimes".
Another fact we found is that if the "xm create" is called by a script the error occurs
very often ~70% of the testcases, while calling the command from a ssh shell manually only fails in
~10% of the testcases. We stripped down the script and it does nothing but calling "xm
create" and the normal shell where it works mostly has no .profile/.bashrc/... that change the
environment.
Additionally there is some persistent behavior - if it failed once it will fail
until the host is rebooted (maybe some config parts are stored and not
re-evaluated). I checked xenstore with the script from
http://wiki.xensource.com/xenwiki/XenStore and saw that xenstore only has the
parameters if a good-case guest is running.
An interesting fact is that it does not fail initializing memory or pci
passthrough in host or guest - somehow it fails the initial config parsing. You
can see below that already the output of XendDomainInfo.create in the log is
different in good/bad case.
Because of the unstable behavior I expect some kind of race condition while
parsing from the files.
### See below for more verbose details on what we found in the log's ,system
setup and configuration files ###
The command "xm create lnudb1 pci=04:01.0 memory=2048" works always successful.
A "xm create lnudb1" creates only *sometimes* a system with a pci adapter and 2
GB memory.
Looking in the /var/log/xend.log reveals a different XendDomainInfo.create statement
for good and bad case.
(I added the >>> <<< signs to point to the important statement)
XendDomainInfo.create(['vm', ['name', 'lnudb1'], ['memory', 2048], ['vcpus', 1],
['on_xend_start', 'ignore'], ['on_xend_stop', 'ignore'], ['image', ['linux',
['kernel', '/etc/xen/vmlinuz-xen'], ['ramdisk', '/etc/xen/initrd-xen'], ['root', '/dev/xvda1'],
['args', 'TERM=xterm selinux=off xencons=tty']]], ['device', ['vbd', ['uname', 'phy:sde5'],
['dev', 'xvda1'], ['mode', 'w']]], ['device', ['vbd', ['uname', 'phy:/dev/hda'], ['dev', 'hdc:cdrom'],
['mode', 'r']]],
['device', ['pci', ['dev', ['domain', '0x0'], ['bus', '0x04'], ['slot', '0x01'],
['func', '0x0']]]], <<<
['device', ['vif', ['bridge', 'xenbr0'], ['mac', '00:16:3e:00:00:10']]],
['device', ['vif', ['bridge', 'xenbr1'],
['mac', '00:16:3e:00:00:31']]], ['device', ['vkbd']], ['device', ['vfb',
['vncunused', '1'], ['type', 'vnc'],
['display', 'localhost:10.0'], ['xauthority', '/root/.Xauthority']]]])
The xm create with the profile described above produces following statement
XendDomainInfo.create(['vm', ['name', 'lnudb1'], ['memory', 1024], ['vcpus', 1],
['on_xend_start', 'ignore'], ['on_xend_stop', 'ignore'], ['image', ['linux',
['kernel', '/etc/xen/vmlinuz-xen'], ['ramdisk', '/etc/xen/initrd-xen'], ['root', '/dev/xvda1'],
['args', 'TERM=xterm selinux=off xencons=tty']]], ['device', ['vbd', ['uname', 'phy:sde5'],
['dev', 'xvda1'], ['mode', 'w']]], ['device', ['vbd', ['uname', 'phy:/dev/hda'], ['dev', 'hdc:cdrom'],
['mode', 'r']]],
<<<<
['device', ['vif', ['bridge', 'xenbr0'], ['mac', '00:16:3e:00:00:10']]],
['device', ['vif', ['bridge', 'xenbr1'],
['mac', '00:16:3e:00:00:31']]], ['device', ['vkbd']], ['device', ['vfb',
['vncunused', '1'], ['type', 'vnc'],
['display', 'localhost:10.0'], ['xauthority', '/root/.Xauthority']]]])
Also note the different values for the memory statement
System Description
Hardware IBM x3950, 4 Intel Xeon CPUs (dual core) 3.5GHz, 23Gb memory.
The operating system is Linux SLES10 SP1, with the following rpms:
o xen-kmp-smp-3.1.0_2.6.16.46_0.12-0.1
o xen-libs-32bit-3.0.4_13138-0.40
o xen-doc-pdf-3.1.0-0.1
o kernel-xen-2.6.16.46-0.12
o xen-3.1.0-0.1
o xen-tools-3.1.0-0.1
o xen-doc-html-3.1.0-0.1
o xen-libs-3.1.0-0.1
o xen-tools-ioemu-3.1.0-0.1
the kernel is booted with the parameters
pciback.hide=(04:01.0)(04:01.1)(06:01.0)(06:01.1)(08:01.0)(08:01.1)
and /etc/modprobe.conf constains the statements
install lpfc /sbin/modprobe pciback ; /sbin/modprobe --first-time --ignore-install lpfc
options pciback hide=(04:01.0)(04:01.1)(06:01.0)(06:01.1)(08:01.0)(08:01.1)
to hide the pci adapters for the Dom0.
The xen profile used is:
builder='linux'
memory = 2048
name = "lnudb1"
vcpus = 1
vif = [ 'mac=00:16:3e:00:00:10, bridge=xenbr0', 'mac=00:16:3e:00:00:31,
bridge=xenbr1' ]
disk = [ 'phy:sde5,xvda1,w', 'phy:/dev/hda,hdc:cdrom,r' ]
root = "/dev/xvda1"
extra = "TERM=xterm selinux=off xencons=tty"
vfb=[ "type=vnc,vncunused=1" ]
pci= [ '0000:04:01.0' ]
The critical parameters are memory and pci, we never saw the issue with e.g.
vif's.
P.S. It was hard to decide between xen-devel and xen-users by topic for that
mail.
Eventually I coose xen-devel becasue I'm already member of this list and
thereby get also responses that may lack a cc to me. Please redirect if needed.
--
Grüsse / regards,
Christian Ehrhardt
IBM Linux Technology Center, Open Virtualization
+49 7031/16-3385
Ehrhardt@xxxxxxxxxxxxxxxxxx
Ehrhardt@xxxxxxxxxx
IBM Deutschland Entwicklung GmbH
Vorsitzender des Aufsichtsrats: Johann Weihen
Geschäftsführung: Herbert Kircher
Sitz der Gesellschaft: Böblingen
Registergericht: Amtsgericht Stuttgart, HRB 243294
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