# Docker File for building image

**URL:** <https://forums.docker.com/t/docker-file-for-building-image/141231>\
**Category:** Image Builds\
**Tags:** docker, build, docker-compose\
**Created:** [May 4, 2024, 1:33pm UTC](https://forums.docker.com/t/docker-file-for-building-image/141231 "2024-05-04T13:33:52Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![niren4ever](https://sea3.discourse-cdn.com/docker/user_avatar/forums.docker.com/niren4ever/32/47500_2.png) [@niren4ever](https://forums.docker.com/u/niren4ever)\
**Post date:** [May 4, 2024, 1:33pm UTC](https://forums.docker.com/t/docker-file-for-building-image/141231/1 "2024-05-04T13:33:52Z")

</div>

Hello-

I want to build a docker image for spring boot with tomcat enabled and JRE 21. I would run it later in Azure DevOps pipeline Agent based on RHEL 8.

I am creating the docker file but confused with the base image. i have created this docker file. Can anyone verify if this docker file i am missing anything ?

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# Use Red Hat Universal Base Image (UBI) 8 as the base image

FROM [registry.access.redhat.com/ubi8/ubi](http://registry.access.redhat.com/ubi8/ubi)

# Set environment variables

ENV JAVA\_HOME=/usr/lib/jvm/java-11-openjdk  
ENV PATH=$PATH:$JAVA\_HOME/bin

# Install OpenJDK 11 (replace with JDK 21 if available)

RUN yum install -y java-11-openjdk-devel &&   
yum clean all

# Copy the Spring Boot application JAR file into the container

COPY target/your-application.jar /app/your-application.jar

# Expose port 8080 for Tomcat

EXPOSE 8080

# Command to run the Spring Boot application

CMD [“java”, “-jar”, “/app/your-application.jar”]

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if i have JDK 21 on my self hosted agent VM, do i need below in docker file

# Install OpenJDK 11 (replace with JDK 21 if available)

RUN yum install -y java-11-openjdk-devel &&   
yum clean all

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<div class="post-metadata">

**Author:** ![meyay](https://sea3.discourse-cdn.com/docker/user_avatar/forums.docker.com/meyay/32/34000_2.png) [@meyay](https://forums.docker.com/u/meyay)\
**Post date:** [May 4, 2024, 1:45pm UTC](https://forums.docker.com/t/docker-file-for-building-image/141231/2 "2024-05-04T13:45:20Z")

</div>

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