Dockerfile for Spring Boot + CRaC

Dockerfile

FROM azul/zulu-openjdk:21-jdk-crac-latest as builder
WORKDIR application

ADD ./.mvn .mvn/
ADD ./mvnw mvnw
ADD ./pom.xml pom.xml
ADD ./src src/
ADD ./.git .git/
RUN ./mvnw -V clean package -DskipTests --no-transfer-progress && \
    cp target/*.jar application.jar && \
    java -Djarmode=layertools -jar application.jar extract

FROM azul/zulu-openjdk:21-jdk-crac-latest
WORKDIR application

COPY --from=builder application/dependencies/ ./
COPY --from=builder application/spring-boot-loader/ ./
COPY --from=builder application/snapshot-dependencies/ ./
COPY --from=builder application/application/ ./
COPY entrypoint.sh ./

ENTRYPOINT ["bash", "/application/entrypoint.sh"]

entrypoint.sh

#!/bin/bash

if [ "$CLEAN_CHECKPOINT" = "true" ] && [ -n "$CHECKPOINT_RESTORE_FILES_DIR" ] && [ -d "$CHECKPOINT_RESTORE_FILES_DIR" ]; then
    rm -f $CHECKPOINT_RESTORE_FILES_DIR/*
fi

mkdir -p $CHECKPOINT_RESTORE_FILES_DIR
export JAVA_TOOL_OPTIONS="${JAVA_TOOL_OPTIONS} -XX:+ExitOnOutOfMemoryError"

if [ -z "$(ls $CHECKPOINT_RESTORE_FILES_DIR/core-*.img 2>/dev/null)" ]; then
  echo "Save checkpoint to $CHECKPOINT_RESTORE_FILES_DIR" 1>&2
  java -XX:CRaCCheckpointTo=$CHECKPOINT_RESTORE_FILES_DIR org.springframework.boot.loader.launch.JarLauncher &
  sleep ${SLEEP_BEFORE_CHECKPOINT:-10}
  jcmd org.springframework.boot.loader.launch.JarLauncher JDK.checkpoint
  sleep ${SLEEP_AFTER_CHECKPOINT:-3}
else
  echo "Restore checkpoint from $CHECKPOINT_RESTORE_FILES_DIR" 1>&2
fi

(echo 128 > /proc/sys/kernel/ns_last_pid) 2>/dev/null || while [ $(cat /proc/sys/kernel/ns_last_pid) -lt 128 ]; do :; done
java -XX:CRaCRestoreFrom=$CHECKPOINT_RESTORE_FILES_DIR &
JAVA_PID=$!

stop_java_app() {
    kill -SIGTERM $JAVA_PID
}

trap stop_java_app SIGINT
wait $JAVA_PID