如何减小 Java 应用程序的 docker 图像大小

Question

i have the following dockerfile code but the image with over 500mb is way to large. I tried to use multi stage build in order so reduce the size but after that the kubernetes deployment wont work.

FROM openjdk:8
ADD target/name_id.jar name_id.jar
EXPOSE 8080
ENTRYPOINT [ "java","-jar","name_id.jar" ]

With this file it works. Can someone help me? For the project itself maven and springboot are used. I also have to clean install the jar everytime if i change something in the code.

Answer 1

Can you use openjdk:8-alpine, size of the base image will be 144.9MB.

Use below image for less size • openjdk:8-jre-alpine: 84 MB

Or you can also try to install alpine os which is 5 MB and openjdk separately and check sizes

Answer 2

Personally, there are two things that come to mind when I think of minimizing the docker image

1. Base Images
2. Multistage Builds

Le me try to answer your question I would used the small jdk image ie openjdk:8-alpine I would used this if I wanted to create the jar file inside the Dockerfile AND execute it. In you case, you just want to use an already existing jar file.

Since you already have and want to use the jar file named name_id.jar, Then you just need the java runtime environment ie openjdk:8-jre-alpine rather than openjdk:8-alpine