Let’s use the base Paketo Builder and the pack CLI to build a Java app
as a runnable container image.
Clone the Paketo samples repository and navigate to the source code for the sample Java app.
git clone https://github.com/paketo-buildpacks/samples \ && cd samples/java/maven
From the sample app directory, use the pack CLI to build an app image.
pack build paketo-demo-app --builder paketobuildpacks/builder-jammy-base
===> DETECTING
7 of 18 buildpacks participating
paketo-buildpacks/ca-certificates 2.3.2
paketo-buildpacks/bellsoft-liberica 8.2.0
paketo-buildpacks/maven 5.3.2
paketo-buildpacks/executable-jar 5.1.2
paketo-buildpacks/apache-tomcat 5.6.1
paketo-buildpacks/dist-zip 4.1.2
paketo-buildpacks/spring-boot 4.4.2
===> ANALYZING
Previous image with name "paketo-demo-app" not found
===> RESTORING
===> BUILDING
Paketo CA Certificates Buildpack 2.3.2
https://github.com/paketo-buildpacks/ca-certificates
Launch Helper: Contributing to layer
Creating /layers/paketo-buildpacks_ca-certificates/helper/exec.d/ca-certificates-helper
Paketo BellSoft Liberica Buildpack 8.2.0
https://github.com/paketo-buildpacks/bellsoft-liberica
Build Configuration:
$BP_JVM_VERSION 11 the Java version
Launch Configuration:
$BPL_JVM_HEAD_ROOM 0 the headroom in memory calculation
$BPL_JVM_LOADED_CLASS_COUNT 35% of classes the number of loaded classes in memory calculation
$BPL_JVM_THREAD_COUNT 250 the number of threads in memory calculation
$JAVA_TOOL_OPTIONS the JVM launch flags
BellSoft Liberica JDK 11.0.12: Contributing to layer
Downloading from https://github.com/bell-sw/Liberica/releases/download/11.0.12+7/bellsoft-jdk11.0.12+7-linux-amd64.tar.gz
Verifying checksum
Expanding to /layers/paketo-buildpacks_bellsoft-liberica/jdk
Adding 129 container CA certificates to JVM truststore
Writing env.build/JAVA_HOME.override
Writing env.build/JDK_HOME.override
BellSoft Liberica JRE 11.0.12: Contributing to layer
Downloading from https://github.com/bell-sw/Liberica/releases/download/11.0.12+7/bellsoft-jre11.0.12+7-linux-amd64.tar.gz
Verifying checksum
Expanding to /layers/paketo-buildpacks_bellsoft-liberica/jre
Adding 129 container CA certificates to JVM truststore
Writing env.launch/BPI_APPLICATION_PATH.default
Writing env.launch/BPI_JVM_CACERTS.default
Writing env.launch/BPI_JVM_CLASS_COUNT.default
Writing env.launch/BPI_JVM_SECURITY_PROVIDERS.default
Writing env.launch/JAVA_HOME.default
Writing env.launch/MALLOC_ARENA_MAX.default
Launch Helper: Contributing to layer
Creating /layers/paketo-buildpacks_bellsoft-liberica/helper/exec.d/active-processor-count
Creating /layers/paketo-buildpacks_bellsoft-liberica/helper/exec.d/java-opts
Creating /layers/paketo-buildpacks_bellsoft-liberica/helper/exec.d/link-local-dns
Creating /layers/paketo-buildpacks_bellsoft-liberica/helper/exec.d/memory-calculator
Creating /layers/paketo-buildpacks_bellsoft-liberica/helper/exec.d/openssl-certificate-loader
Creating /layers/paketo-buildpacks_bellsoft-liberica/helper/exec.d/security-providers-configurer
Creating /layers/paketo-buildpacks_bellsoft-liberica/helper/exec.d/security-providers-classpath-9
JVMKill Agent 1.16.0: Contributing to layer
Downloading from https://github.com/cloudfoundry/jvmkill/releases/download/v1.16.0.RELEASE/jvmkill-1.16.0-RELEASE.so
Verifying checksum
Copying to /layers/paketo-buildpacks_bellsoft-liberica/jvmkill
Writing env.launch/JAVA_TOOL_OPTIONS.append
Writing env.launch/JAVA_TOOL_OPTIONS.delim
Java Security Properties: Contributing to layer
Writing env.launch/JAVA_SECURITY_PROPERTIES.default
Writing env.launch/JAVA_TOOL_OPTIONS.append
Writing env.launch/JAVA_TOOL_OPTIONS.delim
Paketo Maven Buildpack 5.3.2
https://github.com/paketo-buildpacks/maven
Build Configuration:
$BP_MAVEN_BUILD_ARGUMENTS -Dmaven.test.skip=true package the arguments to pass to Maven
$BP_MAVEN_BUILT_ARTIFACT target/*.[jw]ar the built application artifact explicitly. Supersedes $BP_MAVEN_BUILT_MODULE
$BP_MAVEN_BUILT_MODULE the module to find application artifact in
Creating cache directory /home/cnb/.m2
Compiled Application: Contributing to layer
Executing mvnw --batch-mode -Dmaven.test.skip=true package
[INFO] Scanning for projects...
[INFO] Downloading from central: https://repo.maven.apache.org/maven2/org/springframework/boot/spring-boot-starter-parent/2.5.3/spring-boot-starter-parent-2.5.3.pom
[INFO] Downloaded from central: https://repo.maven.apache.org/maven2/org/springframework/boot/spring-boot-starter-parent/2.5.3/spring-boot-starter-parent-2.5.3.pom (8.6 kB at 19 kB/s)
[INFO] Downloading from central: https://repo.maven.apache.org/maven2/org/springframework/boot/spring-boot-dependencies/2.5.3/spring-boot-dependencies-2.5.3.pom
...
[INFO] Replacing main artifact with repackaged archive
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 01:32 min
[INFO] Finished at: 2021-08-12T18:22:25Z
[INFO] ------------------------------------------------------------------------
Removing source code
Paketo Executable JAR Buildpack 5.1.2
https://github.com/paketo-buildpacks/executable-jar
Class Path: Contributing to layer
Writing env/CLASSPATH.delim
Writing env/CLASSPATH.prepend
Process types:
executable-jar: java org.springframework.boot.loader.JarLauncher (direct)
task: java org.springframework.boot.loader.JarLauncher (direct)
web: java org.springframework.boot.loader.JarLauncher (direct)
Paketo Spring Boot Buildpack 4.4.2
https://github.com/paketo-buildpacks/spring-boot
Creating slices from layers index
dependencies
spring-boot-loader
snapshot-dependencies
application
Launch Helper: Contributing to layer
Creating /layers/paketo-buildpacks_spring-boot/helper/exec.d/spring-cloud-bindings
Spring Cloud Bindings 1.7.1: Contributing to layer
Downloading from https://repo.spring.io/release/org/springframework/cloud/spring-cloud-bindings/1.7.1/spring-cloud-bindings-1.7.1.jar
Verifying checksum
Copying to /layers/paketo-buildpacks_spring-boot/spring-cloud-bindings
Web Application Type: Contributing to layer
Reactive web application detected
Writing env.launch/BPL_JVM_THREAD_COUNT.default
4 application slices
Image labels:
org.opencontainers.image.title
org.opencontainers.image.version
org.springframework.boot.version
===> EXPORTING
Adding layer 'paketo-buildpacks/ca-certificates:helper'
Adding layer 'paketo-buildpacks/bellsoft-liberica:helper'
Adding layer 'paketo-buildpacks/bellsoft-liberica:java-security-properties'
Adding layer 'paketo-buildpacks/bellsoft-liberica:jre'
Adding layer 'paketo-buildpacks/bellsoft-liberica:jvmkill'
Adding layer 'paketo-buildpacks/executable-jar:classpath'
Adding layer 'paketo-buildpacks/spring-boot:helper'
Adding layer 'paketo-buildpacks/spring-boot:spring-cloud-bindings'
Adding layer 'paketo-buildpacks/spring-boot:web-application-type'
Adding 5/5 app layer(s)
Adding layer 'launcher'
Adding layer 'config'
Adding layer 'process-types'
Adding label 'io.buildpacks.lifecycle.metadata'
Adding label 'io.buildpacks.build.metadata'
Adding label 'io.buildpacks.project.metadata'
Adding label 'org.opencontainers.image.title'
Adding label 'org.opencontainers.image.version'
Adding label 'org.springframework.boot.version'
Setting default process type 'web'
Saving paketo-demo-app...
*** Images (b18bb0f43aca):
paketo-demo-app
Adding cache layer 'paketo-buildpacks/bellsoft-liberica:jdk'
Adding cache layer 'paketo-buildpacks/maven:application'
Adding cache layer 'paketo-buildpacks/maven:cache'
Successfully built image paketo-demo-app
Let’s start an instance of our app and interact with it.
Run the app image with Docker. It will receive incoming requests on localhost:8080.
docker run -d -p 8080:8080 -e PORT=8080 paketo-demo-app
Wait a few moments for the app to start. Then, use curl to check the status of the app.
curl -s http://localhost:8080/actuator/health | jq .
{
"status": "UP"
}