Tanzu Application Platform uses Cloud Native Buildpacks by default when creating application container images.
You can also use Docker to build Docker images.
Recommendations on how to write a Dockerfile for Spring Boot apps can be found in the following document.
https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#container-images.dockerfiles
The Dockerfile described in the document assumes that the jar has already been built, but since there is only the source code on the Tanzu Application Platform,
I need to build a jar file from source code when docker build. Also, runAsUser: 1000 is set at runtime, so switch to the user with uid 1000.
Based on the above, if you write a Dockerfile, it will be as follows.
FROM eclipse-temurin:17-jdk as builder
WORKDIR application
ADD ./.mvn .mvn/
ADD ./mvnw mvnw
ADD ./pom.xml pom.xml
ADD ./src src/
RUN ./mvnw -V clean package -DskipTests --no-transfer-progress && \
cp target/*.jar application.jar && \
java -Djarmode=layertools -jar application.jar extract
FROM eclipse-temurin:17-jre
ARG USERNAME=spring
ARG GROUPNAME=spring
ARG UID=1000
ARG GID=1000
WORKDIR application
RUN groupadd -g $GID $GROUPNAME && \
useradd -m -s /bin/bash -u $UID -g $GID $USERNAME
USER $USERNAME
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"]
When deploying, if you specify --param dockerfile=<Dockerfile path on repository> as follows, a container image will be built using Dockerfile.
tanzu apps workload apply rest-service \
--app rest-service \
--git-repo https://github.com/making/rest-service \
--git-branch main \
--type web \
--param dockerfile=./Dockerfile \
-n demo \
-y
Unlike when creating a container image with Paketo Buildpacks / Tanzu Buildpacks, the JVM memory size is not automatically set, so
Note that you need to configure the JVM with the runtime environment variable JAVA_TOOL_OPTIONS if necessary.