remove 2021.06 version from pilot EESSI CVMFS repo

[boegel]

Since we're no longer making changes to the 2021.06 pilot version, we should remove /cvmfs/pilot.eessi-hpc.org/2021.06.

No objections were raised against this in the EESSI Slack or in today's EESSI update meeting.

We should "archive" the contents of /cvmfs/pilot.eessi-hpc.org/2021.06 though.
The easiest way (for now) would be to just create tarballs, perhaps separate for the different CPU families x86_64, aarch64, ppc64le)

[bedroge]

I've created tarballs of the 2021.06 stack (one per CPU family), and uploaded them to the AWS bucket eessi-archive. An announcement of the removal has been sent to the mailing list and slack, so without any objection I'll remove it from the repo next week. As @ocaisa proposed in #141, we could replace the 2021.06 directory by a symlink to something like /cvmfs/pilot.eessi-hpc.org/host_injections/versions/2021.06? Or even a variant symlink which can be changed by the admin of the system, and by default points to that host_injections path?

[ocaisa]

Maybe we should make a new symlink archive that operates the same as host_injections:

/cvmfs/pilot.eessi-hpc.org/archive

and then you would unpack under

/cvmfs/pilot.eessi-hpc.org/archive/2021.06

which would unbreak the symlink

/cvmfs/pilot.eessi-hpc.org/versions/2021.06 -> /cvmfs/pilot.eessi-hpc.org/archive/2021.06

[ocaisa]

Since an archive is likely to be pretty large, it might be a better approach to separate it from host_injections rather than force them into the same location

[bedroge]

Yeah, that's perhaps more appropriate than host_injections. Do we want to set a default path for the variant symlink (e.g. /opt/eessi/archive?)? Maybe we shouldn't, as I doubt if people will be using /opt for this?

[bedroge]

By the way, 2021.06 was originally built/installed to /cvmfs/pilot.eessi-hpc.org/2021.06 (without versions, which was added later on), and we now have a symlink versions/2021.06 -> 2021.06. I would really like to get rid of that 2021.06 dir in the root of the repo, but not having it anymore would mean that stuff could/will break... So I guess we really do have to keep it, maybe until we switch to the new eessi.io domain/repo?

[boegel]

Plan:

1. Remove 2021.06

rm -rf /cvmfs/pilot.eessi-hpc.org/2021.06
rm /cvmfs/pilot.eessi-hpc.org/versions/2021.06

2. Create replacement init scripts for 2021.06

cfr. EESSI/software-layer#246

mkdir -p /cvmfs/pilot.eessi-hpc.org/versions/2021.06/init/
cp -a software-layer/versions/2021.06/init/* /cvmfs/pilot.eessi-hpc.org/versions/2021.06/init/

[boegel]

As an additional step, we could introduce variant symlinks so you can inject the 2021.06 compat/software layer back:

/cvmfs/pilot.eessi-hpc.org/versions/2021.06/compat
/cvmfs/pilot.eessi-hpc.org/versions/2021.06/software

This allow locally injecting the 2021.06 EESSI pilot back using the tarball available in eessi-archive S3 bucket...

[bedroge]

This was done by printing a deprecation message and automatically loading 2021.12, see: https://github.com/EESSI/software-layer/tree/main/versions/2021.06/init.