Initial commit of Jenkins script + README

And a config description. This doesn't yet have much - first want to
make sure I can do the build job. Next I'll submit the e2e script with
its twiddles and switch those over. (After going to 3 e2es, I think
it's finally time for version control.)

hack/jenkins/build.sh

@@ -0,0 +1,54 @@
+#!/bin/bash
+
+# Copyright 2015 Google Inc. 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.
+
+# kubernetes-build job: Triggered by github checkins on a 5 minute
+# poll. We abort this job if it takes longer than 10m. (Typically this
+# job takes about ~5m as of 0.8.0, but it's actually not completely
+# hermetic right now due to things like the golang image. It can take
+# ~8m if you force it to be totally hermetic.)
+
+set -o errexit
+set -o nounset
+set -o pipefail
+set -o xtrace
+
+# !!! ALERT !!! Jenkins default $HOME is /var/lib/jenkins, which is
+# global across jobs. We change $HOME instead to ${WORKSPACE}, which
+# is an incoming variable Jenkins provides us for this job's scratch
+# space.
+export HOME=${WORKSPACE} # Nothing should want Jenkins $HOME
+export PATH=$PATH:/usr/local/go/bin
+export KUBE_RELEASE_RUN_TESTS=n
+export KUBE_SKIP_CONFIRMATIONS=y
+
+# Clean stuff out.
+#
+# TODO: Look at git clean plugin again for hermeticism, but may not
+# play nicely with dockerized stuff and permissions. (We may just need
+# to force the build/make-clean.sh at the end of the build regardless
+# of status and be delicate with the exit status.) (Low priority
+# unless there's a hermetic issue.)
+rm -rf ~/.kube*
+./build/make-clean.sh
+git clean -fdx
+
+# Build
+go run ./hack/e2e.go -v -build
+
+# Push to GCS
+yes | ./build/push-ci-build.sh
+
+sha256sum _output/release-tars/kubernetes*.tar.gz