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

[Daniel Henrique Barboza]

On 04/26/2016 06:29 PM, Paulo Ricardo Paz Vital wrote:
> 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.
Do we have a standard way in WoK to disable a plug-in? If not, this would
be a good place to start.

Note that if libvirtd service is down -> kimchi down then it would make 
sense
to consider libvirtd up -> kimchi up, preferably without reloading WoK
service. Not sure if this is feasible though.

>
> 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/
>
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