[kolla] Plan to deprecate and finally drop the chrony container
Hello Fellow OpenStackers interested in Kolla's way.
The topic should be pretty self-explanatory but let me provide the details and background.
We are currently working on the Wallaby release and, since we are cycle-trailing, it is the right moment for us to reflect upon the various cleanup plans we had (and have). One of those is the drop of the chrony container. Chrony serves the time synchronization purpose which is required for healthy operations (I hope I don't need to explain this point further, time sync is essential for most services nowadays). It is still deployed by default by Kolla Ansible. The point is, most default (even minimal ones) host OS installations come with some form of NTP client, be it chrony, ntpd, timesyncd or whatever else there is. :-) This applies also to provisioning solutions like MAAS or Foreman. And Kolla Ansible actually stands on its head to detect and disable those to avoid multiple time sync daemons hell as it may disrupt normal operations (mostly due to having different time sources but also due to different compensation algorithms [or rather just their actual configuration] and the fact that each tool assumes to be the only source of time changes). We seem to have placed a relatively sane precheck to detect this but effective disabling may prove tricky, especially since it is very easy to get it installed at any point. The NTP client is considered a very basic service these days. It also seems that several users known to us do not use the chrony container and instead orchestrate timesync elsewhere.
Hence, our current plan is to: 1) Deprecate the chrony container in the Wallaby cycle. - in Kolla Ansible this would mean also warning users that they use it and defaulting to not using it (with docs and a reno); docs would suggest an Ansible way to coordinate timesync - in Kolla docs and a reno 2) Drop the chrony container from both the places
I know Kayobe (the "highest-level" member of the Kolla project) is planning to incorporate timesync handling by external Ansible role means so their users should be covered.
Please let us know if you have any comments on the plan above. Or generally any suggestions you would like us to hear.
Cheers!
-yoctozepto
I have not received any more feedback on this so I have started the deprecation process. [1]
[1] https://review.opendev.org/q/topic:deprecate-chrony
-yoctozepto
On Thu, Feb 25, 2021 at 7:02 PM Radosław Piliszek radoslaw.piliszek@gmail.com wrote:
Hello Fellow OpenStackers interested in Kolla's way.
The topic should be pretty self-explanatory but let me provide the details and background.
We are currently working on the Wallaby release and, since we are cycle-trailing, it is the right moment for us to reflect upon the various cleanup plans we had (and have). One of those is the drop of the chrony container. Chrony serves the time synchronization purpose which is required for healthy operations (I hope I don't need to explain this point further, time sync is essential for most services nowadays). It is still deployed by default by Kolla Ansible. The point is, most default (even minimal ones) host OS installations come with some form of NTP client, be it chrony, ntpd, timesyncd or whatever else there is. :-) This applies also to provisioning solutions like MAAS or Foreman. And Kolla Ansible actually stands on its head to detect and disable those to avoid multiple time sync daemons hell as it may disrupt normal operations (mostly due to having different time sources but also due to different compensation algorithms [or rather just their actual configuration] and the fact that each tool assumes to be the only source of time changes). We seem to have placed a relatively sane precheck to detect this but effective disabling may prove tricky, especially since it is very easy to get it installed at any point. The NTP client is considered a very basic service these days. It also seems that several users known to us do not use the chrony container and instead orchestrate timesync elsewhere.
Hence, our current plan is to:
- Deprecate the chrony container in the Wallaby cycle.
- in Kolla Ansible this would mean also warning users that they use it
and defaulting to not using it (with docs and a reno); docs would suggest an Ansible way to coordinate timesync
- in Kolla docs and a reno
- Drop the chrony container from both the places
I know Kayobe (the "highest-level" member of the Kolla project) is planning to incorporate timesync handling by external Ansible role means so their users should be covered.
Please let us know if you have any comments on the plan above. Or generally any suggestions you would like us to hear.
Cheers!
-yoctozepto
participants (1)
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Radosław Piliszek