Use Spring Boot layered jars to optimize Docker images

docker-compose.yml

@@ -14,7 +14,7 @@ services:
     mem_limit: 512M
     depends_on:
       - config-server
-    entrypoint: ["./dockerize","-wait=tcp://config-server:8888","-timeout=60s","--","java", "-XX:+UnlockExperimentalVMOptions", "-XX:+UseCGroupMemoryLimitForHeap", "-Djava.security.egd=file:/dev/./urandom","-jar","/app.jar"]
+    entrypoint: ["./dockerize","-wait=tcp://config-server:8888","-timeout=60s","--","java", "org.springframework.boot.loader.JarLauncher"]
     ports:
      - 8761:8761
 
@@ -25,7 +25,7 @@ services:
     depends_on:
      - config-server
      - discovery-server
-    entrypoint: ["./dockerize","-wait=tcp://discovery-server:8761","-timeout=60s","--","java", "-XX:+UnlockExperimentalVMOptions", "-XX:+UseCGroupMemoryLimitForHeap", "-Djava.security.egd=file:/dev/./urandom","-jar","/app.jar"]
+    entrypoint: ["./dockerize","-wait=tcp://discovery-server:8761","-timeout=60s","--","java", "org.springframework.boot.loader.JarLauncher"]
     ports:
     - 8081:8081
 
@@ -36,7 +36,7 @@ services:
     depends_on:
      - config-server
      - discovery-server
-    entrypoint: ["./dockerize","-wait=tcp://discovery-server:8761","-timeout=60s","--","java", "-XX:+UnlockExperimentalVMOptions", "-XX:+UseCGroupMemoryLimitForHeap", "-Djava.security.egd=file:/dev/./urandom","-jar","/app.jar"]
+    entrypoint: ["./dockerize","-wait=tcp://discovery-server:8761","-timeout=60s","--","java", "org.springframework.boot.loader.JarLauncher"]
     ports:
      - 8082:8082
 
@@ -47,7 +47,7 @@ services:
     depends_on:
      - config-server
      - discovery-server
-    entrypoint: ["./dockerize","-wait=tcp://discovery-server:8761","-timeout=60s","--","java", "-XX:+UnlockExperimentalVMOptions", "-XX:+UseCGroupMemoryLimitForHeap", "-Djava.security.egd=file:/dev/./urandom","-jar","/app.jar"]
+    entrypoint: ["./dockerize","-wait=tcp://discovery-server:8761","-timeout=60s","--","java", "org.springframework.boot.loader.JarLauncher"]
     ports:
      - 8083:8083
 
@@ -58,7 +58,7 @@ services:
     depends_on:
      - config-server
      - discovery-server
-    entrypoint: ["./dockerize","-wait=tcp://discovery-server:8761","-timeout=60s","--","java", "-XX:+UnlockExperimentalVMOptions", "-XX:+UseCGroupMemoryLimitForHeap", "-Djava.security.egd=file:/dev/./urandom","-jar","/app.jar"]
+    entrypoint: ["./dockerize","-wait=tcp://discovery-server:8761","-timeout=60s","--","java", "org.springframework.boot.loader.JarLauncher"]
     ports:
      - 8080:8080
 
@@ -78,7 +78,7 @@ services:
     depends_on:
      - config-server
      - discovery-server
-    entrypoint: ["./dockerize","-wait=tcp://discovery-server:8761","-timeout=60s","--","java", "-XX:+UnlockExperimentalVMOptions", "-XX:+UseCGroupMemoryLimitForHeap", "-Djava.security.egd=file:/dev/./urandom","-jar","/app.jar"]
+    entrypoint: ["./dockerize","-wait=tcp://discovery-server:8761","-timeout=60s","--","java", "org.springframework.boot.loader.JarLauncher"]
     ports:
      - 9090:9090
 

docker/Dockerfile

@@ -1,19 +1,31 @@
-FROM openjdk:8-jre-alpine
-VOLUME /tmp
+FROM openjdk:11-jre as builder
+WORKDIR application
+ARG ARTIFACT_NAME
+COPY ${ARTIFACT_NAME}.jar application.jar
+RUN java -Djarmode=layertools -jar application.jar extract
 
 # Download dockerize and cache that layer
 ARG DOCKERIZE_VERSION
 RUN wget -O dockerize.tar.gz https://github.com/jwilder/dockerize/releases/download/${DOCKERIZE_VERSION}/dockerize-alpine-linux-amd64-${DOCKERIZE_VERSION}.tar.gz
 RUN tar xzf dockerize.tar.gz
 RUN chmod +x dockerize
 
-# This is the first layer that won't be cached
-ARG ARTIFACT_NAME
-ADD ${ARTIFACT_NAME}.jar /app.jar
+
+# wget is not installed on adoptopenjdk:11-jre-hotspot
+FROM adoptopenjdk:11-jre-hotspot
+
+WORKDIR application
+
+# Dockerize
+COPY --from=builder application/dockerize ./
 
 ARG EXPOSED_PORT
 EXPOSE ${EXPOSED_PORT}
 
 ENV SPRING_PROFILES_ACTIVE docker
 
-ENTRYPOINT ["java", "-XX:+UnlockExperimentalVMOptions", "-XX:+UseCGroupMemoryLimitForHeap", "-Djava.security.egd=file:/dev/./urandom","-jar","/app.jar"]
+COPY --from=builder application/dependencies/ ./
+COPY --from=builder application/spring-boot-loader/ ./
+COPY --from=builder application/snapshot-dependencies/ ./
+COPY --from=builder application/application/ ./
+ENTRYPOINT ["java", "org.springframework.boot.loader.JarLauncher"]

pom.xml

@@ -72,6 +72,7 @@
         </dependencies>
     </dependencyManagement>
 
+
     <profiles>
         <profile>
             <id>springboot</id>
@@ -88,6 +89,10 @@
                         <artifactId>spring-boot-maven-plugin</artifactId>
                         <configuration>
                             <fork>true</fork>
+                            <!-- Layered jars optimizes Docker images -->
+                            <layers>
+                                <enabled>true</enabled>
+                            </layers>
                         </configuration>
                         <executions>
                             <execution>