[CentOS-devel] CentOS Stream image retention policies

Thu May 25 12:14:55 UTC 2023
Ewoud Kohl van Wijngaarden <ewoud+centos at kohlvanwijngaarden.nl>

On Wed, May 24, 2023 at 07:49:23AM -0700, Troy Dawson wrote:
>It was pointed out that we don't have CentOS Stream's image retention
>policies written down anywhere.  We're in the process of getting those up
>into the docs section.  But I figured an email would get them out quicker
>while we work on that.

Thanks for writing down policies, that's always great because it allows 
for discussion.

>CentOS Stream Image Retention Policies:
>
>* Images on CentOS Cloud:
>https://cloud.centos.org/centos/8-stream/
>https://cloud.centos.org/centos/9-stream/
>** Policy: All images are kept for a month.  After that, we only keep one
>set of compose images per month, for up to a year.  (I hope that makes
>sense)
>** Images: container, ec2, qcow, vagrant

The removal of older images hit us, since we need to point to specific 
versions in our Vagrant config. I know this is on the roadmap[1], but 
just pointing out the relationship.

Another thing to note is that for a while it was nice to be able to use 
an older version due to a systemd bug[2]. This may have been unfortunate 
timing. When I read your Policy I somehow thought that only images for 
the past month were kept but when I look at cloud.centos.org I see older 
images still exist.

It looks like it comes down to:

* For the past month: all images are kept
* For the past year: monthly images are kept
* Older: images are removed

Now month is an odd thing (and dates really are painful in computing). 
For example, if you're half way in the month, do you take the number of 
days in the current month or the previous. Should it be week based?
(and perhaps the implementation is already that).

Now tying these two discussions together: when an image is removed from 
cloud.centos.org, it should also be removed from Vagrant Cloud.

[1]: https://issues.redhat.com/browse/CS-1186
[2]: https://bugzilla.redhat.com/show_bug.cgi?id=2174645