Set up multistage Docker build.

By setting up a multistage Docker build, we can create the container
image in a single command. This eliminates external setup and allows us
to build this automatically on registries.

Dockerfile

@@ -11,9 +11,16 @@
 # 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.
+FROM golang:1.9.2
+
+WORKDIR /go/src/github.com/kubernetes-incubator/descheduler
+COPY . .
+RUN make
+
 FROM scratch
 
 MAINTAINER Avesh Agarwal <avagarwa@redhat.com>
 
-COPY _output/bin/descheduler /bin/descheduler
+COPY --from=0 /go/src/github.com/kubernetes-incubator/descheduler/_output/bin/descheduler /bin/descheduler
+
 CMD ["/bin/descheduler", "--help"]

Dockerfile.dev

@@ -0,0 +1,20 @@
+# Copyright 2017 The Kubernetes Authors.
+#
+# 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.
+FROM scratch
+
+MAINTAINER Avesh Agarwal <avagarwa@redhat.com>
+
+COPY _output/bin/descheduler /bin/descheduler
+
+CMD ["/bin/descheduler", "--help"]

Makefile

@@ -32,7 +32,10 @@ all: build
 build:
 	CGO_ENABLED=0 go build ${LDFLAGS} -o _output/bin/descheduler github.com/kubernetes-incubator/descheduler/cmd/descheduler
 
-image: build
+dev-image: build
+	docker build -f Dockerfile.dev -t $(IMAGE) .
+
+image:
 	docker build -t $(IMAGE) .
 
 clean: