script: Drop KVM support in gitian-build.py #21140

The python-vm-builder package, which is required for KVM-based builds, is not available in distros after bionic.

Concept ACK as discussed in #bitcoin-builds

2021-02-10 10:14:27     hebasto `python-vm-builder` package is not available in distros after bionic; should we maintain the `--kvm` option for `gitian-build.py` script?
2021-02-10 10:15:39     hebasto wumpus: luke-jr: ^
2021-02-10 10:16:55     wumpus  i personally always use LXC
2021-02-10 10:17:08     hebasto me too :)
2021-02-10 10:17:10     wumpus  so ok with removing it, unless someone got it to work some other way
2021-02-10 10:17:44     wumpus  i dono't really know why one'd prefer to use KVM, there's no reason to use a low level VM here
2021-02-10 10:19:14     hebasto anyway, it is still possible to make kvm-based gitian builds w/o python helper script, right?
2021-02-10 10:21:43     wumpus  yes
2021-02-10 10:37:49     wumpus  i think removing it is fine
2021-02-10 10:38:11     wumpus  it can still be used for old releases, with the build script on that branch
2021-02-10 10:38:25     wumpus  but not on 22.x which builds with focal

Concept NACK. Ubuntu isn't the only distro out there.

Besides, vmbuilder doesn't even work to create bionic either, so it's been irrelevant for a while. It's not very hard to install in KVM manually.

@luke-jr So do you use this script at all, or call gitian-build directly? In the latter case this doesn't affect you.

Ubuntu isn't the only distro out there.

Sure, but Ubuntu is the only distro used for building bitcoin core gitian binaries. Which is what this script is for. Nothing else…

At present I have a custom script that is similar, but this isn't about me personally...

Sure, but Ubuntu is the only distro used for building bitcoin core gitian binaries.

Within gitian, yes, but not the only one outside gitian.

Within gitian, yes, but not the only one outside gitian.

This script is only relevant to gitian. It's not called gitian-build.py for nothing.

Rebased b4bc7208294d34c1407a4e30a6a0ac45b96dea43 -> ef14d90172e2278b362171763805ac41a6d7779e (pr21140.01 -> pr21140.02) due to the conflict with #21130.

This script is only relevant to gitian. It's not called gitian-build.py for nothing.

Yes, and gitian runs fine on non-Ubuntu platforms... The only Ubuntu-specific thing about (our) gitian usage is the OS run within the VM gitian manages.

ACK ef14d90172e2278b362171763805ac41a6d7779e

I think it's better to close this. There are clear differences in opinion here and it's unclear how much debating a small cleanup like this even matters with the move to GUIX in progress (and this script disappearing completely).

I think it's better to close this.

Agree. There's not really any harm to leave this as-is for now.

I think it's better to close this. There are clear differences in opinion here and it's unclear how much debating a small cleanup like this even matters with the move to GUIX in progress (and this script disappearing completely).

Right.