Create base image for admission service

Makefile

@@ -44,6 +44,9 @@ images: image_bins
 		rm installer/dockerfile/$$name/vk-$$name; \
 	done
 
+admission-base-image:
+	docker build --no-cache -t $(IMAGE_PREFIX)-admission-base:$(TAG) ./installer/dockerfile/admission/ -f ./installer/dockerfile/admission/Dockerfile.base;
+
 generate-code:
 	./hack/update-gencode.sh
 

installer/dockerfile/admission/Dockerfile

@@ -13,17 +13,9 @@
 # limitations under the License.
 
 
-FROM alpine:latest
-
-# Install requirements
-ARG KUBE_VERSION="1.13.1"
-RUN apk add --update ca-certificates && \
-    apk add --update openssl && \
-    apk add --update -t deps curl && \
-    curl -L https://storage.googleapis.com/kubernetes-release/release/v$KUBE_VERSION/bin/linux/amd64/kubectl -o /usr/local/bin/kubectl && \
-    chmod +x /usr/local/bin/kubectl && \
-    apk del --purge deps && \
-    rm /var/cache/apk/*
+# The base image is created via `Dockerfile.base`, the base image is cached
+# since the required packages change very rarely.
+FROM volcanosh/vk-admission-base:latest
 
 ADD vk-admission /vk-admission
 ADD gen-admission-secret.sh /gen-admission-secret.sh

installer/dockerfile/admission/Dockerfile.base

@@ -0,0 +1,28 @@
+# Copyright 2019 The Volcano 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 alpine:latest
+
+# Install requirements for admission service
+# Install requirements
+ARG KUBE_VERSION="1.13.1"
+RUN apk add --update ca-certificates && \
+    apk add --update openssl && \
+    apk add --update -t deps curl && \
+    curl -L https://storage.googleapis.com/kubernetes-release/release/v$KUBE_VERSION/bin/linux/amd64/kubectl -o /usr/local/bin/kubectl && \
+    chmod +x /usr/local/bin/kubectl && \
+    apk del --purge deps && \
+    rm /var/cache/apk/*
+ENTRYPOINT []