[Bug 585964] Re: Libvirtd -- error: monitor socket did not show up.: Connection refused

[Hovanes Manucharyan]

I was able to reproduce this issue again for the 3rd time on a clean
install. I believe that anybody can reproduce this with the following
steps:

STEP 1: Do a clean Ubuntu Server 10.04 installation. When I installed, I
selected "OpenSSH server" as the only additional installation package.

STEP 2: Install libvirt-bin package.

I installed it as such: apt-get install eucalyptus-nc

This downloaded libvirt-bin as a dependency.

After I installed Eucalyptus NC and configured the node properly I
verified that this node was able to execute my images properly.
Everything worked fine. As part of configuring Eucalyptus-NC, I also
created a bridge br0 to my eth0 dev.

STEP 3: Edit /etc/libvirt/qemu.conf

Config change:

security_driver = "none"

I restarted libvirt-bin and verified again that everything was working
fine.

This step may have a benign effect or it may act in combination with
STEP 4 to cause the issue.

STEP 4: Purge apparmor package & reboot

root at srv-uec-qa-node01:~# apt-get purge apparmor
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages will be REMOVED:
  apparmor* apparmor-utils*
0 upgraded, 0 newly installed, 2 to remove and 9 not upgraded.
After this operation, 4,067kB disk space will be freed.
Do you want to continue [Y/n]? y
(Reading database ... 44060 files and directories currently installed.)
Removing apparmor-utils ...
Purging configuration files for apparmor-utils ...
Removing apparmor ...
 * Unloading AppArmor profiles                                                                                                                        [ OK ] 
Purging configuration files for apparmor ...
dpkg: warning: while removing apparmor, directory '/etc/apparmor.d/cache' not empty so not removed.
Processing triggers for man-db ...
Processing triggers for ureadahead ...
ureadahead will be reprofiled on next reboot

----

Then I reboot.

=============================================================================

After STEP4 my problem is reproduced. I get the following error when I
try to run vm instances using libvirtd:

root at srv-uec-qa-node01:/var/lib/eucalyptus/instances/admin/i-5AF109A2# virsh start i-5AF109A2
error: Failed to start domain i-5AF109A2
error: monitor socket did not show up.: Connection refused


Thus, the problem is either STEP4 by itself or combination of STEP 3 + STEP 4.

------

Even if I don't purge apparmor but disable it with a kernel param
(apparmor=0), the problem repeats itself, suggesting libvirtd relies on
the presence of apparmor in order to function properly.

------

I haven't had 100% success fixing libvirt after this.

In one case, reinstalling apparmor seemed to make libvirtd work again.

However, in another case I wasn't successful. On this system I had
disabled apparmor using a kernel boot param. Additionally, this system
was in a "broken" state for several days and may have seen other changes
beside the boot param. I undid my modifications to the kernel boot
parameters, rebooted, reinstalled apparmor, but the problem persisted.

-- 
Libvirtd  --  error: monitor socket did not show up.: Connection refused
https://bugs.launchpad.net/bugs/585964
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