[nova][powervm][zvm] Time to mark powervm and zvm drivers as deprecated for removal?
I've had a PR open against the pypowervm library for over a fortnight now [1] with no activity. This has prompted me to go looking into the state of the powervm driver and what I've found isn't great. It doesn't seem there has been any feature development on the driver for many years, and the last change I can see that wasn't simply of a case of "I need to do this to get tests to pass" was over three years ago [2]. The CI also doesn't appear to have been touched in years.
The situation for zvm isn't any better. The last functional change to that driver was nearly 2 years ago and I wasn't able to spot any CI running (though it's possible I just missed this).
This means the powervm and zvm drivers stand out from the other non-libvirt drivers in-tree, each of which are getting at least some activity (albeit out- of-tree for Hyper-V, from what I recall). It also begs the question: are these drivers something we want to keep around? If we do, how are we going to maintain them long term? If not, how aggressive should we be in removing that now dead code?
I'll open patches to mark both powervm and zvm as deprecated shortly so that, assuming nothing changes in the interim, we can look to remove it early in the Z cycle. Please respond here or on the reviews if you have concerns.
Stephen
[1] https://github.com/powervm/pypowervm/pull/17 [2] Change ID I89ad36f19672368a1f795e1f29c5af6368ccfeec
On Thu, 2021-11-25 at 18:45 +0000, Stephen Finucane wrote:
I've had a PR open against the pypowervm library for over a fortnight now [1] with no activity. This has prompted me to go looking into the state of the powervm driver and what I've found isn't great. It doesn't seem there has been any feature development on the driver for many years, and the last change I can see that wasn't simply of a case of "I need to do this to get tests to pass" was over three years ago [2]. The CI also doesn't appear to have been touched in years.
The situation for zvm isn't any better. The last functional change to that driver was nearly 2 years ago and I wasn't able to spot any CI running (though it's possible I just missed this).
This means the powervm and zvm drivers stand out from the other non-libvirt drivers in-tree, each of which are getting at least some activity (albeit out- of-tree for Hyper-V, from what I recall). It also begs the question: are these drivers something we want to keep around? If we do, how are we going to maintain them long term? If not, how aggressive should we be in removing that now dead code?
I'll open patches to mark both powervm and zvm as deprecated shortly so that, assuming nothing changes in the interim, we can look to remove it early in the Z cycle. Please respond here or on the reviews if you have concerns.
Reviving this thread. Since I posted about this, jichenjc has helpfully piped up and noted that ZVM is very much alive and all the logic simply lives in a separate library [1]. However, the pypowervm PR is still stalled and it seems no one is monitoring this or cares. It also seems this is hindering multiple projects [2]. [3] and [4] will mark the driver as deprecated and move dependencies to 'extras' (meaning they're not installed by default). I suggest we merge these sooner rather than later to signal to potential users that this driver is not long for the world unless something changes.
Cheers, Stephen
[1] https://review.opendev.org/c/openstack/nova/+/819365 [2] https://github.com/powervm/pypowervm/pull/17#issuecomment-978122930 [3] https://review.opendev.org/c/openstack/nova/+/819366 [4] https://review.opendev.org/c/openstack/nova/+/822749
Stephen
[1] https://github.com/powervm/pypowervm/pull/17 [2] Change ID I89ad36f19672368a1f795e1f29c5af6368ccfeec
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Stephen Finucane