Fuse 7 Images with FatJar versus ThinJar
Sample repo of Red Hat Developer Blog Post
This example demonstrates how build Fuse 7 on Spring Boot images with two different approaches:
- FatJar: Application packaged as original Spring Boot Application
- ThinJar: Application divided into application and dependencies
This example tries to show you how both approaches create different layers in Docker images. Those layers could help you in your deployment pipelines.
The quickstart uses Spring Boot to configure a little application that includes a Camel route that triggers a message every 5th second, and routes the message to a log.
Requirements
This project needs a Docker daemon to build the final images. Please review your environment to have access to a Docker daemon.
Building a FatJar Image
The example can be built with
mvn clean package -Pfuse7-sb-fatjar
Inspecting your image
Listing your current images
$ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
fuse7-sb-sample-fatjar 1.0.0-SNAPSHOT 83b0a7014e66 About a minute ago 472MB
History of your fatjar image
$ docker image history fuse7-sb-sample-fatjar:1.0.0-SNAPSHOT
IMAGE CREATED CREATED BY SIZE COMMENT
83b0a7014e66 3 minutes ago /bin/sh -c #(nop) COPY dir:6f1bc8060e84f24fd… 22.5MB
3acce9532a02 5 weeks ago 29.7MB
<missing> 5 weeks ago 204MB
<missing> 5 weeks ago 12.6MB
<missing> 5 weeks ago 2.92kB
<missing> 5 weeks ago 203MB Imported from -
Building a ThinJar Image
The example can be built with
mvn clean package -Pfuse7-sb-thinjar
Inspecting your image
Listing your current images
$ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
fuse7-sb-sample-thinjar 1.0.0-SNAPSHOT 3d1f14d211d3 4 seconds ago 472MB
History of your thinjar image
$ docker image history fuse7-sb-sample-thinjar:1.0.0-SNAPSHOT
IMAGE CREATED CREATED BY SIZE COMMENT
3d1f14d211d3 45 seconds ago /bin/sh -c #(nop) COPY file:a8e6ca81de366678… 5.92kB
8f85633e632f 45 seconds ago /bin/sh -c #(nop) COPY dir:9371efeba146b0c49… 22.4MB
3acce9532a02 5 weeks ago 29.7MB
<missing> 5 weeks ago 204MB
<missing> 5 weeks ago 12.6MB
<missing> 5 weeks ago 2.92kB
<missing> 5 weeks ago 203MB Imported from -
Running images
The example can be run using:
$ docker run fuse7-sb-sample-fatjar:1.0.0-SNAPSHOT
$ docker run fuse7-sb-sample-thinjar:1.0.0-SNAPSHOT
When the containers are running, you can inspect the logs with
docker logs <name of container>
Both cases should log similar messages:
Starting the Java application using /opt/run-java/run-java.sh ...
exec java -javaagent:/opt/jolokia/jolokia.jar=config=/opt/jolokia/etc/jolokia.properties -javaagent:/opt/prometheus/jmx_prometheus_javaagent.jar=9779:/opt/prometheus/prometheus-config.yml -XX:+UseParallelGC -XX:GCTimeRatio=4 -XX:AdaptiveSizePolicyWeight=9
0 -XX:MinHeapFreeRatio=20 -XX:MaxHeapFreeRatio=40 -XX:+ExitOnOutOfMemoryError -cp . -jar /deployments/fuse7-sb-sample-docker-fatjar-vs-docker-thinjar-1.0.0-SNAPSHOT.jar
I> No access restrictor found, access to any MBean is allowed
Jolokia: Agent started with URL http://172.17.0.2:8778/jolokia/
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v1.5.16.RELEASE)
09:44:19.314 [main] INFO org.jboss.fuse7.samples.Application - Starting Application on 9c92300a6c84 with PID 1 (/deployments/fuse7-sb-sample-docker-fatjar-vs-docker-thinjar-1.0.0-SNAPSHOT.jar started by jboss in /deployments)
09:44:19.318 [main] INFO org.jboss.fuse7.samples.Application - No active profile set, falling back to default profiles: default
...
09:44:28.993 [main] INFO o.s.b.a.e.jmx.EndpointMBeanExporter - Located managed bean 'healthEndpoint': registering with JMX server as MBean [org.springframework.boot:type=Endpoint,name=healthEndpoint]
09:44:29.133 [main] INFO o.s.b.c.e.u.UndertowEmbeddedServletContainer - Undertow started on port(s) 8080 (http)
09:44:29.138 [main] INFO org.jboss.fuse7.samples.Application - Started Application in 10.313 seconds (JVM running for 11.374)
09:44:29.802 [Camel (Fuse7-SB-Sample-Docker-FatJar-vs-ThinJar) thread #1 - timer://foo] INFO route1 - >>> Hello World
Comparing Docker Images
Initial conclusions:
- Final images have the same final size. No difference as final image.
- Same application running
Main Differences:
-
Each time we build the fatjar application the layer with the application is replaced completely (around 22Mb)
$ mvn clean package -Pdocker-fatjar $ docker image history fuse7-sb-sample-fatjar:1.0.0-SNAPSHOT IMAGE CREATED CREATED BY SIZE COMMENT fc90862260bf 17 seconds ago /bin/sh -c #(nop) COPY dir:23bf52db17b0a0aaa… 22.5MB
-
Each time we build the thinjar application, only the layer with the application is replace completely (around 6Kb). Docker cache is used and then only one layer is changed in the final image.
$ mvn clean package -Pdocker-thinjar $ docker image history fuse7-sb-sample-thinjar:1.0.0-SNAPSHOT IMAGE CREATED CREATED BY SIZE COMMENT b62a83bd5286 8 seconds ago /bin/sh -c #(nop) COPY file:23ff2a06a7e2e24d… 5.92kB
8f85633e632f 16 minutes ago /bin/sh -c #(nop) COPY dir:9371efeba146b0c49… 22.4MB
We could improve our deployment pipelines if we use a thinjar strategy for our classes. Normally the dependencies only change in few cases and they are very stable.
This sample is very simple and small, but sometimes your applications could be so heavies and then build and deployment process will take longer time and increase the resources.