Build nightly runsc releases with Kokoro.

PiperOrigin-RevId: 196129010
Change-Id: I655eb3eecf24ffff475b3882ec55a8b55e6d2f36

kokoro/gcp_ubuntu/release-nightly.cfg

@@ -0,0 +1,9 @@
+# Location of bash script that builds a release.
+build_file: "repo/kokoro/gcp_ubuntu/run_build.sh"
+
+action {
+  # Upload only the runsc binary.
+  define_artifacts {
+    regex: "runsc"
+  }
+}

kokoro/gcp_ubuntu/run_build.sh

@@ -0,0 +1,35 @@
+#!/bin/bash
+
+# Copyright 2018 Google Inc.
+#
+# 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.
+
+# Fail on any error.
+set -e
+# Display commands to stderr.
+set -x
+
+# Install the latest version of Bazel.
+use_bazel.sh latest
+
+# Log the bazel path and version.
+which bazel
+bazel version
+
+cd git/repo
+
+# Build runsc.
+bazel build //runsc
+
+# Move the built binary to the top of the artifacts directory.
+mv bazel-bin/runsc/linux_amd64_pure_stripped/runsc "${KOKORO_ARTIFACTS_DIR}"/runsc