Docker layers
- every instruction in dockerfile (cmd, entrypoint, workdir, copy, add, user, from).
- all layers will be read only
FROM ubuntu:latest
RUN apt update && apt-get install openjdk-17-jdk -y && apt-get install maven git -y
RUN git clone https://github.com/spring-projects/spring-petclinic.git
WORKDIR spring-petclinic
"Layers": [
"sha256:4a6e4a6c5956212bf74c556250eb0028096f13d74501e43af51a1dbed8d69749",
"sha256:4f41b99e67b8aeaedacb31ca888054a4b877577371f0bbe01196e136d2793635",
"sha256:d1a934b98182759aeaa02239e8f05208da4c3c2df0eb94a9af72989b21c14d32",
"sha256:e5a3840f1f51b9c292b67e667a7327e56c7ce29c796b7fa22973c9d26e99dee9",
"sha256:5f70bf18a086007016e948b04aed3b82103a36bea41755b6cddfaf10ace3c6ef"
]
"Layers": [
"sha256:4a6e4a6c5956212bf74c556250eb0028096f13d74501e43af51a1dbed8d69749",
"sha256:4f41b99e67b8aeaedacb31ca888054a4b877577371f0bbe01196e136d2793635",
"sha256:d1a934b98182759aeaa02239e8f05208da4c3c2df0eb94a9af72989b21c14d32",
"sha256:4cd00040cb7c9469f573dbf938fc8077dc1582f476a310f500c7dcdfec85a649",
"sha256:5f70bf18a086007016e948b04aed3b82103a36bea41755b6cddfaf10ace3c6ef"
]
FROM ubuntu:latest
RUN apt update && apt-get install openjdk-17-jdk -y && apt-get install maven git -y
RUN git clone https://github.com/spring-projects/spring-framework.git
WORKDIR spring-framework
keypoints
- immutable: once build a layer never change and new instruction will create new layer
- cached: reusefull layer for multiple images. save disk storage
- read-only : all layer in image will be readonly
- Ordered: layers will be applicable to Dockerfile order
Layer will be having wirte access when you run image as container
docker run- Docker run will have R/W access
FROM ubuntu:latest
RUN apt update
RUN apt-get install openjdk-17-jdk -y
RUN apt-get install maven -y
RUN apt-get install git -y
RUN git clone https://github.com/spring-projects/spring-petclinic.git
WORKDIR spring-petclinic
