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

[Paulo Ricardo Paz Vital]

On Apr 28 10:32AM, Aline Manera wrote:
>
>
> On 04/27/2016 09:47 PM, Daniel Henrique Barboza wrote:
> >
> >
> >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.
> >
> In case user is on Kimchi UI and libvirt goes down, IMO we should not reload
> Wok to remove Kimchi tabs, instead of that we should informe user through a
> notification that libvirt went down and Kimchi will not work properly.
>

>From my preliminary tests, Wok will not be reloaded if libvirt goes down.
However any feature that needs libvirt will not work (and then I'll warn user
about that) and will automatically works when libvirt goes up.

> >>
> >>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/
> >>
> >>_______________________________________________
> >>Kimchi-devel mailing list
> >>Kimchi-devel at ovirt.org
> >>http://lists.ovirt.org/mailman/listinfo/kimchi-devel
> >
> >_______________________________________________
> >Kimchi-devel mailing list
> >Kimchi-devel at ovirt.org
> >http://lists.ovirt.org/mailman/listinfo/kimchi-devel
> >
>
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--
Paulo Ricardo Paz Vital
Linux Technology Center, IBM Systems
http://www.ibm.com/linux/ltc/