Dynamically setting the JVM memory limit by reading the Cgroup

core/java8/Dockerfile

@@ -37,4 +37,6 @@ RUN cd /javaAction \
 	&& rm -rf /javaAction/src \
 	&& ./compileClassCache.sh
 
-CMD ["java", "-Dfile.encoding=UTF-8", "-Xshareclasses:cacheDir=/javaSharedCache,readonly", "-Xquickstart", "-jar", "/javaAction/build/libs/javaAction-all.jar"]
+ADD init.sh ./
+RUN chmod 777 ./init.sh
+CMD ["./init.sh"]

core/java8/init.sh

@@ -0,0 +1,34 @@
+#!/usr/bin/env bash
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You 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.
+#
+
+limit_in_bytes=$(cat /sys/fs/cgroup/memory/memory.limit_in_bytes)
+heap_size=64
+export JAVA_OPTS="-Dfile.encoding=UTF-8 -Xshareclasses:cacheDir=/javaSharedCache,readonly -Xquickstart"
+export RESERVED_MEGABYTES=64
+
+# If not default limit_in_bytes in cgroup
+if [ "$limit_in_bytes" -ne "9223372036854771712" ]
+then
+    limit_in_megabytes=$(expr $limit_in_bytes \/ 1048576)
+    heap_size=$(expr $limit_in_megabytes - $RESERVED_MEGABYTES)
+    export JAVA_OPTS="-Xmx${heap_size}m $JAVA_OPTS"
+fi
+
+echo JAVA_OPTS= $JAVA_OPTS
+
+java $JAVA_OPTS -jar /javaAction/build/libs/javaAction-all.jar