Docker

Concepts

Dockerhub

Dockerfile

# file: Dockerfile

Docker Compose

Need an OS with Java installed - One such image is amazoncorretto amazoncorretto - different images for same java version based on feature included

• alpine :

# file: docker-compose.yml
FROM amazoncorretto:21.0.2-alpine3.19       # Base image to provide os and jdk
COPY build/libs/my-app.jar app.jar          # copy the jar to root of the OS
ENTRYPOINT ["java","-jar","/app.jar"]       # java -jar build/libs/app.jar

docker build -t a04t/imagename:v01 .        # intel
docker build  --platform linux/amd64 -t a04t/imagename:v01 . # mac chips

Package Managers in base images

• There are several Linux distributions and the different ways they manage packages.
• Knowing how to use multiple package managers can prove life-saving for downloading or installing software from repositories, plus updating, handling dependencies and uninstalling software.
• Example - Dockerfile with `` will have apt package available which can be explored here
• 5 Best Linux Package Managers for Linux Newbies

FROM gradle:5.6.2-jdk11

RUN apt-get update && apt-get install -y bash git curl zip unzip locales

Difference between Docker Images

• Difference Between Openjdk Docker Images: Slim vs Slim-Stretch vs Stretch vs Alpine