Also, fix the healthchecking configuration for the master components, which
was previously only working by coincidence:
If a kubelet doesn't register with a master, it never bothers to figure out
what its local address is. In which case it ends up constructing a URL like
http://:8080/healthz for the http probe. This happens to work on the master
because all of the pods are using host networking and explicitly binding to
127.0.0.1. Once the kubelet is registered with the master and it determines
the local node address, it tries to healthcheck on an address where the pod
isn't listening and the kubelet periodically restarts each master component
when the liveness probe fails.
This PR changes how we version going forward in the following ways:
* mark-new-version.sh is changed to a new policy of just splitting
branches, rather than the old backmerge policy, as discussed in
vX.Y.0, and a tag for vX.(Y+1).0-alpha.0 back to master.
* I eliminated PRs back to master by making the version/base.go
gitVersion and gitCommit just be `export-subst`. I testing that this
works with GitHub's source export tarballs. There's no reason to
bother with forcing the version into `base.go` (especially twice). The
tarball versions outside a git tree aren't perfect (master looks like
"v0.0.0+hash", and the release branches look more accurate), but our
build contract has never allowed that version is perfect in this
situation, so I think we can relax this.
* That master tag gets picked up by "git describe" on master, so e.g.
master would have immediately become v1.1.0-alpha.0
* In order to be more semVer compatible, the gitVersion field for the
master branch now looks something like 1.1.0-alpha.0.6+84c76d1142ea4d.
This is a tiny translation of the "git describe". I did this because
there are a ton of consumers out there of the "gitVersion" field
expecting it to be the full version, but it would be nice if this
field were actually semver compliant. (1.1.0-alpha.0-6-84c76d1142ea4d
is, but it's not *usefully* so.)
Fixes#11495
Primary motivation: enable GKE and other cluster-as-a-service folks to
easily run additional logic on the master without having to modify salt
or SSH to the master after it's been created.
Issue #11012 reported that disk contents may be lost (sometimes).
We should have an e2e test to verify this is not happening.
(If it is happening, we should then fix it!)
