Prepare for CentOS7 EOL

[sxa]

We are currently using CentOS6/7 containers to build Temurin most of our major Linux platforms. CentOS7 (the last one still in support is being stopped atht end of June 2024. Sine this is the final versions it is entirely possible that some extra cleanup will occur which may also affect the CentOS6 images we build on. Some bullet points:

• We currently adjust out CentOS6 dockerfile to use vault.centos.org as the packages were moved there. It seems likely from this blog post that this will happen for 7 too The packages will be archived on vault.centos.org after May 31, 2024. As a minimum we'll have to do a similar switch of the location that we have for CentOS6 (PR)
• As a precaution we could look at archiving the CentOS/RHEL rpm files that we require for the devkit creation.
• We should consider the possibility that the docker images at dockerhub may disappear and perhaps archive those for each architecture locally (including RHEL7 for s390x) so we can continue to base our docker images builds on that.

[andrew-m-leonard]

PMC agenda:

• Centos7 rpms are likely to be archived to vault.centos.org, but as a precaution should we archive them locally? These are needed to build the Linux DevKit
• dockerhub centos7 images may dissappear, meaning we would be unable to re-build the adoptopenjdk/centos7_build_image. Should we store these images locally?
• Is there anything else that might be affected?