[libvirt] RFC: Drop unmaintained hv drivers? (phyp, xenapi, hyperv)

[Cole Robinson]

On 04/18/2016 05:21 AM, Daniel P. Berrange wrote:
> On Fri, Apr 15, 2016 at 03:54:00PM -0400, Cole Robinson wrote:
>> Hi all,
>>
>> There's a few old hypervisor drivers in the tree that haven't been actively
>> maintained for a long time. I'm curious if anyone knows of these drivers being
>> actively used. If not I think we should consider dropping them
>>
>>
>> src/phyp/ : for power VM hypervisor. Added in July 2009. The last commit that
>> looks like it wasn't either internal API conversion, or caught by code
>> analysis, is:
>>
>> commit 41461ff7f7d6ee6679aae2a8004e305c5830c9e8
>> Author: Eduardo Otubo <otubo at linux.vnet.ibm.com>
>> Date:   Tue Apr 19 12:34:08 2011 -0300
>>
>>     PHYP: Adding reboot domain function
>>
>>     Adding reboot <domain> function for pHyp driver.
>>
>> Nearly 5 years ago. Eduardo is the primary driver author too (CCd at his email
>> from github).
>>
>> Searching the upstream bug tracker for all bugs with 'phyp', the only one
>> that's actually about the phyp driver is a report from 2 years ago that it
>> crashes trying to open a connection:
>>
>> https://bugzilla.redhat.com/show_bug.cgi?id=1093094
> 
> The phyp driver would have a fairly niche end user audience, so it would
> not be entirely surprising to not hear much about it.
> 
> 
>> src/xenapi/: Connecting to a xen api server. Added in March 2010. Largely
>> appears to be a code drop, the original author/committer has never had another
>> commit. The last xenapi specific commit seems to be:
>>
>> commit 484460ec4678a264c5e7355495c2f0da72cb42bd
>> Author: Matthias Bolte <matthias.bolte at googlemail.com>
>> Date:   Thu Jul 21 15:16:11 2011 +0200
>>
>>     xenapi: Improve error reporting in xenapiOpen once again
>>
>> Nearly 5 years ago. The only upstream bug that was filed about xenapi is:
>>
>> https://bugzilla.redhat.com/show_bug.cgi?id=711372
>>
>> Which was about a connection failure that was eventually fixed upstream, and
>> dovetailed into the above referenced commit. Current xen guys, you know of
>> anyone using this?
> 
> The XenAPI driver was never "finished" as IIRC the person who started work
> on it, left XenSource before he was able to make it functional enough to
> be useful. The XenAPI was targetting the closed source Xen products, as
> opposed to the open source platform, which is now libxl based. I did vaguely
> remember talk of the Xen products eventualy moving over to be libxl based
> instead of XenAPi, but I don't know if that's actually accurate or not.
> 
>> src/hyperv/: Added in July 2011. This was largely a code drop as well;
>> committed and patched a few times by Matthias but it was a university project
>> by someone else. Last hyperv targeted patch was:
>>
>> commit 9e9ea3ead9825bd1dc2c17cea4abc8c4165591d0
>> Author: Matthias Bolte <matthias.bolte at googlemail.com>
>> Date:   Sun Sep 9 17:39:40 2012 +0200
>>
>>     hyperv: Fix and improve hypervListAllDomains
>>
>> The driver is fairly minimal as well: it can only list existing VMs and
>> perform lifecycle operations. It can't create new VMs, and doesn't list VM
>> device config AFAICT.
> 
> This is a fairly similar level of functionality to the XenAPI driver, but
> I'm pretty loathe for us to loose even the limited hyperv support, as it
> is very  much an active product that's not going away.
> 
> 
> In general I'm not really in favour of dropping virt drivers for hypervisor
> platforms that still exist and have potential users, even if we don't hear
> much about them. I don't think any of these drivers is really giving us a
> significant maintenance headache to justify deletion.
> 

It's just kind of a weird situation. We advertise support for these platforms,
but if someone tries them and finds them lacking and reports an issue here,
the only response they are going to get is 'no one has worked on it for years,
no one here has a setup to test, sorry we cannot help you'. That's if they get
a response at all. Seems bizarre to me...

- Cole