Update the java8 template to honor cgroups memory limits

This commit upgrades the openjdk version to the earliest that supports
cgroup memory limits. It also applies the JVM arguments required to
enable the support.

This change is needed for the JVM to recognize the actual memory
made available to it via the container instead of believing it has
access to the amount of memory possessed by the node running the
container.

Signed-off-by: Chad Taylor <[email protected]>

Author: tessellator

template/java8/Dockerfile

@@ -1,4 +1,4 @@
-FROM openjdk:8u121-jdk-alpine as builder
+FROM openjdk:8u131-jdk-alpine as builder
 
 RUN apk --no-cache add curl \
     && addgroup -S app && adduser -S -g app app \
@@ -22,7 +22,7 @@ COPY . /home/app/
 
 RUN gradle build
 
-FROM openjdk:8u121-jdk-alpine as ship
+FROM openjdk:8u131-jdk-alpine as ship
 RUN apk --no-cache add curl \
     && echo "Pulling watchdog binary from Github." \
     && curl -sSL https://github.com/openfaas-incubator/of-watchdog/releases/download/0.4.6/of-watchdog > /usr/bin/fwatchdog \
@@ -41,7 +41,7 @@ ENV upstream_url="http://127.0.0.1:8081"
 ENV mode="http"
 ENV CLASSPATH="/home/app/entrypoint-1.0/lib/*"
 
-ENV fprocess="java com.openfaas.entrypoint.App"
+ENV fprocess="java -XX:+UnlockExperimentalVMOptions -XX:+UseCGroupMemoryLimitForHeap com.openfaas.entrypoint.App"
 EXPOSE 8080
 
 HEALTHCHECK --interval=2s CMD [ -e /tmp/.lock ] || exit 1