Automatic merge from submit-queue (batch tested with PRs 38277, 36361, 38452)
Add options for build container rsync optimization
KUBE_RSYNC_COMPRESS env var sets rsync compression level.
KUBE_RSYNC_GENERATED_TO_BUILD_CONTAINER env var disables rsyncing
generated files to build containers.
Why KUBE_RSYNC_COMPRESS is needed -- from rsync manual on `--compress` option (implied by non-zero `--compress-level`):
> Note that this option typically achieves better compression ratios than can be achieved by using a compressing remote shell or a compressing transport because it takes advantage of the implicit information in the matching data blocks that are not explicitly sent over the connection.
Use case for `KUBE_RSYNC_GENERATED_TO_BUILD_CONTAINER`: when you sometimes build stuff locally (e.g. `make WHAT=cmd/kubectl`) and sometimes do it on remote docker (`build-tools/run.sh make WHAT=cmd/hyperkube`), local builds touch generated files which causes them to be rsynced to the build data container, which may slow down the builds. Still, I'm not sure whether local->remote rsync of generated files is useful (e.g. someone may want to edit generated files for debugging purposes?), so I made not rsyncing these files an option instead of forcing such behavior.
Automatic merge from submit-queue
Don't require docker or other tools when running `make clean`
**What this PR does / why we need it**: we don't require `docker` for a local build, so we shouldn't require it for `make clean` either.
**Which issue this PR fixes**: fixes#37690
cc @sebgoa
This check is too restrictive if building into multiple _output
targets, such as the way anago produces releases
When branching we build essentially 2 copies of the same thing
(GKE requirement) the second build will always fail because the
docker image is the same.