Add instructions and tooling for munging test infra for a new release series

docs/devel/releasing.md

@@ -217,14 +217,30 @@ Finally, from a clone of upstream/master, *make sure* you still have
 `RELEASE_VERSION` set correctly, and run `./build/mark-stable-release.sh
 ${RELEASE_VERSION}`.
 
-### Updating the master branch
-
-If you are cutting a new release series, please also update the master branch:
-change the `latestReleaseBranch` in `cmd/mungedocs/mungedocs.go` to the new
-release branch (`release-X.Y`), run `hack/update-generated-docs.sh`. This will
-let the unversioned warning in docs point to the latest release series. Please
-send the changes as a PR titled "Update the latestReleaseBranch to release-X.Y
-in the munger".
+### Manual tasks for new release series
+
+*TODO(#20946) Burn this list down.*
+
+If you are cutting a new release series, there are a few tasks that haven't yet
+been automated that need to happen after the branch has been cut:
+
+1. Update the master branch constant for doc generation: change the
+   `latestReleaseBranch` in `cmd/mungedocs/mungedocs.go` to the new release
+   branch (`release-X.Y`), run `hack/update-generated-docs.sh`.  This will let
+   the unversioned warning in docs point to the latest release series. Please
+   send the changes as a PR titled "Update the latestReleaseBranch to
+   release-X.Y in the munger".
+1. Add test jobs for the new branch.  See [End-2-End Testing in
+   Kubernetes](e2e-tests.md) for the test jobs that run in CI, which are under
+   version control in `hack/jenkins/e2e.sh` (on the release branch) and
+   `hack/jenkins/job-configs/kubernetes-e2e.yaml` (in `master`).  You'll want
+   to duplicate/munge these for the release branch so that, as we cherry-pick
+   fixes onto the branch, we know that it builds, etc.
+1. Make sure all features that are supposed to be GA are covered by tests.  You
+   can use `hack/list-feature-tests.sh` to see a list of tests labeled as
+   `[Feature:.+]`; make sure that these are all either covered in CI jobs or
+   are experimental features.  (The answer should already be 'yes', but this is
+   a good time to reconcile.)
 
 ## Injecting Version into Binaries
 

hack/list-feature-tests.sh

+#!/bin/bash
+
+# Copyright 2016 The Kubernetes Authors All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# A single script that lists all of the [Feature:.+] tests in our e2e suite.
+set -o errexit
+set -o nounset
+set -o pipefail
+
+KUBE_ROOT=$(dirname "${BASH_SOURCE}")/..
+grep "\[Feature:(.+?)\]" "${KUBE_ROOT}"/test/e2e/*.go -Poh | sort | uniq