The aim of this repo is to measure some features of an Spring Boot application and its Docker image. Instead of creating a new Spring Boot demo from scratch, it is based on Spring PetClinic.
Build PetClinic application:
git clone https://github.com/wearearima/spring-boot-docker-size.git
cd spring-boot-docker-size
./mvnw clean package
Measure the jar files:
ls -lh target/*.jar*
Result:
-rw-r--r-- 1 inigotelleria staff 43M Sep 2 17:05 target/spring-petclinic-2.1.0.BUILD-SNAPSHOT.jar
-rw-r--r-- 1 inigotelleria staff 371K Sep 2 17:05 target/spring-petclinic-2.1.0.BUILD-SNAPSHOT.jar.original
The file named spring-petclinic-2.1.0.BUILD-SNAPSHOT is the resulting fat jar because it includes
PetClinic's code and its dependencies. The other file, suffixed .original, is just PetClinic's code
without its dependencies. The result is that our code size is 371KB and the dependencies' 43MB.
Build PetClinic's Docker image:
./mvnw jib:dockerBuild
Measure the image size:
docker image ls | grep spring-petclinic
Result:
org.springframework.samples/spring-petclinic 2.1.0.BUILD-SNAPSHOT b0379064ade1 49 years ago 136MB
We can see that size of the artifact has increased from 43MB to 136MB. This is mainly because the
Docker image includes the JDK and Linux images. Run this command to check it:
docker image history org.springframework.samples/spring-petclinic
The result shows the different layers added to the Docker image:
Inigos-MacBook-Pro:spring-petclinic inigo$ docker image history org.springframework.samples/spring-petclinic
IMAGE CREATED CREATED BY SIZE COMMENT
e3718c1a3f02 49 years ago jib-maven-plugin:1.5.1 47.8kB classes
<missing> 49 years ago jib-maven-plugin:1.5.1 941kB resources
<missing> 49 years ago jib-maven-plugin:1.5.1 44.7MB dependencies
<missing> 2 days ago /bin/sh -c #(nop) ENV JAVA_HOME=/opt/java/o… 0B
<missing> 2 days ago /bin/sh -c set -eux; apk add --no-cache … 75.7MB
<missing> 2 days ago /bin/sh -c #(nop) COPY multi:cf4be6a9ef2b0c0… 15.6kB
<missing> 2 days ago /bin/sh -c #(nop) ENV JAVA_VERSION=jdk8u222… 0B
<missing> 2 days ago /bin/sh -c apk add --no-cache --virtual .bui… 8.88MB
<missing> 2 days ago /bin/sh -c #(nop) ENV LANG=en_US.UTF-8 LANG… 0B
<missing> 3 weeks ago /bin/sh -c #(nop) CMD ["/bin/sh"] 0B
<missing> 3 weeks ago /bin/sh -c #(nop) ADD file:fe64057fbb83dccb9… 5.58MB
The 5.58MB image is the Alpine Linux image and the 75.7MB image is the JDK8 image. The sum of all layers results in
an image of 136MB which includes Linux OS, JDK8, PetClinic's code and dependencies' jar.
Different Linux image comparison at https://github.com/gliderlabs/docker-alpine#why
Run PetClinic application with this command:
java -jar target/spring-petclinic-2.1.0.BUILD-SNAPSHOT.jar
The applications starts en 5,54 seconds using AdoptOpenJDK 1.8.0_222-b10:
Started PetClinicApplication in 5.54 seconds (JVM running for 5.902)
After navigating through the application to make sure all beans are loaded, open JConsole or other profiler such as
YourKit. Measure the heap after executing Garbage Collector (GC).
With no load the application's heap consumption is around 60MB . However, the memory consumption is bigger than just the
heap, so let's measure it using ps command:
Inigos-MacBook-Pro:spring-boot-docker-size inigo$ ps aux 14526
USER PID %CPU %MEM VSZ RSS TT STAT STARTED TIME COMMAND
inigo 14526 0.0 4.0 10241740 669648 s004 S+ 4:25PM 0:33.05 /usr/bin/java -jar target/spring-petclinic-2.1.0.BUILD-SNAPSHOT.jar
We can see that PetClinic's process actually is using almost 650MB of memory.
Interesting resource about measuring Spring Boot: https://spring.io/blog/2015/12/10/spring-boot-memory-performance
| Feature | |
|---|---|
| Spring Boot App disk usage | 43M |
| Spring Boot App disk usage (without dependencies) | 371KB |
| Docker Container disk usage | 136MB |
| Spring Boot App startup time | 5,54 seconds |
| Spring Boot App heap consumption | 60MB |
| Spring Boot App memory usage | 650MB |
Original PetClinic by https://www.spring.io
Docker configuration by https://www.arima.eu
