[Kimchi-devel] [RFC] Issue 201 - Kimchi should handle libvirt connection failures

[Paulo Ricardo Paz Vital]

Today, Kimchi (and Ginger) has a strong dependency with Libvirt, well described
in the kimchid.service.{fedora,ubuntu} file that extends the wokd.service
configuration to make it dependent of libvirt service. The current configuration
stops wokd service automatically if libvirt service is stopped.

To prevent wokd to stop automatically if libvirt stops, a new configuration must
be set up and loaded, making wokd service still available to user. This is the
easiest part to solve this issue.

The real issue is that most of the Kimchi operations need to connect to libvirt
service and the current implementation, simple stops the cherrypy server if a
connection is not available (after 10 seconds trying to connect), causing a
"502 bad gateway" error from NGINX. With this implementation from Kimchi, Wok
and GingerBase (and Ginger if installed) will not be available to user even
though they don't depend on the libvirt service.

Basically, the proposal to solve the issue is:

1) Modify the kimchid.service.{fedora,ubuntu} files to "reduce" the dependency
on libvirt service while wokd is already running - none change will modify the
start up dependency; and

2) Modify how Kimchi handle the missing libvirt connection to no stop the
cherrypy server and provide information to user by Virtualization tab and its
sub-tabs, keeping all other plugins enabled and operating.

Feel free to make any suggestion. Patches will be submitted by the end of this
week.

Thanks and best regards,
--
Paulo Ricardo Paz Vital
Linux Technology Center, IBM Systems
http://www.ibm.com/linux/ltc/