Merge branch 'master' into openj9

CONFLICT (content): Merge conflict in Dockerfile

.circleci/config.yml

@@ -0,0 +1,25 @@
+version: 2
+jobs:
+  minecraft_server:
+    docker:
+      - image: circleci/buildpack-deps:stable
+    steps:
+      - checkout
+      - setup_remote_docker
+      - run:
+          name: Build image
+          command: docker build -t itzg/minecraft-server:${CIRCLE_BRANCH} .
+#      - run:
+#          name: Build arm v7 image
+#          command: docker build -t itzg/minecraft-server:${CIRCLE_BRANCH}-arm-v7 --platform linux/arm/v7 --build-arg ARCH=armv7 .
+
+workflows:
+  version: 2
+  build:
+    jobs:
+      - minecraft_server:
+          filters:
+            branches:
+              ignore:
+                - armv7
+                - multiarch

Dockerfile

@@ -1,4 +1,4 @@
-FROM adoptopenjdk/openjdk11:alpine-jre
+FROM adoptopenjdk/openjdk8-openj9:alpine
 
 LABEL org.opencontainers.image.authors="Geoff Bourne <itzgeoff@gmail.com>"
 
@@ -70,7 +70,7 @@ COPY log4j2.xml /tmp/log4j2.xml
 WORKDIR /data
 
 ENV UID=1000 GID=1000 \
-  JVM_XX_OPTS="-XX:+UseG1GC" MEMORY="1G" \
+  MEMORY="1G" \
   TYPE=VANILLA VERSION=LATEST \
   ENABLE_RCON=true RCON_PORT=25575 RCON_PASSWORD=minecraft \
   SERVER_PORT=25565 ONLINE_MODE=TRUE SERVER_NAME="Dedicated Server" \

README.md

@@ -1150,6 +1150,14 @@ via a `JVM_XX_OPTS` environment variable.
 For some cases, if e.g. after removing mods, it could be necessary to startup minecraft with an additional `-D` parameter like `-Dfml.queryResult=confirm`. To address this you can use the environment variable `JVM_DD_OPTS`, which builds the params from a given list of values separated by space, but without the `-D` prefix. To make things running under systems (e.g. Plesk), which doesn't allow `=` inside values, a `:` (colon) could be used instead. The upper example would look like this:
 `JVM_DD_OPTS=fml.queryResult:confirm`, and will be converted to `-Dfml.queryResult=confirm`.
 
+The container uses [OpenJ9](https://www.eclipse.org/openj9/docs) and a couple of J9 options are
+simplified by environment variables:
+
+- `-e TUNE_VIRTUALIZED=TRUE` : enables the option to 
+  [optimize for virtualized environments](https://www.eclipse.org/openj9/docs/xtunevirtualized/)
+- `-e TUNE_NURSERY_SIZES=TRUE` : configures nursery sizes where the initial size is 50%
+  of the `MAX_MEMORY` and the max size is 80%.
+
 ### Enable Remote JMX for Profiling
 
 To enable remote JMX, such as for profiling with VisualVM or JMC, add the environment variable `ENABLE_JMX=true` and add a port forwarding of TCP port 7091, such as:

start-minecraftFinalSetup

@@ -83,6 +83,23 @@ if [ -n "$JVM_DD_OPTS" ]; then
       done
 fi
 
+if isTrue ${TUNE_VIRTUALIZED}; then
+  JVM_XX_OPTS="${JVM_XX_OPTS} -Xtune:virtualized"
+fi
+
+if isTrue ${TUNE_NURSERY_SIZES}; then
+  case ${MAX_MEMORY^^} in
+    *G)
+      MAX_MEMORY_MB=$(( ${MAX_MEMORY%?} * 1024 )) ;;
+    *M)
+      MAX_MEMORY_MB=${MAX_MEMORY%?} ;;
+  esac
+
+  NURSERY_MINIMUM=$(( ${MAX_MEMORY_MB} / 2 ))
+  NURSERY_MAXIMUM=$(( ${MAX_MEMORY_MB} * 4/5 ))
+  JVM_XX_OPTS="${JVM_XX_OPTS} -Xmns${NURSERY_MINIMUM}M -Xmnx${NURSERY_MAXIMUM}M"
+fi
+
 if isTrue ${ENABLE_JMX}; then
   : ${JMX_HOST:=0.0.0.0}
   : ${JMX_PORT:=7091}