Hello to all the readers!
There is multi stage build in which the build time and run time dependencies are separated.
For example JDK is required to build java app but JDK is not required in final image to be run.
FROM maven AS build
WORKDIR /app
COPY . .
RUN mvn package
FROM tomcat
COPY --from=build /app/target/file.war /usr/local/tomcat/webapps We copy only executable files from build stage that has to run thereby reducing the docker image size.
Hello to all the readers! I am writing down about my learnings on docker. I have learnt docker in the past and used it but never thought to document my learning. I think it is very good to document our own learning of a subject that helps me and maybe you to understand it in…
Hello to all the readers! Any data that is generated inside a container by operations is lost once container is stopped. Therefore in order to persist the data in a container, volumes are created and attached to the container. Now we will run a container created out of getting-started image and mount the volume to…
A warm Hello to all the readers! This is yet another article to understand a new concept of Docker. There is a special file called as Dockerfile. What is Dockerfile? Dockerfile is a file that contains instructions to build an image. Instructions are a series of commands that you will otherwise run in running container…
Hello to all the readers! In this post I will be creating a docker image out of the simple tutorial posted on Docker’s documentation. Let us begin with the steps. Clone the repository Create Dockerfile. Dockerfile is a set of instructions to build the docker image. Next is to build the image. This builds the…
Hello to all the readers! There is another concept of bind mounts in docker that allows to share the host machine directory inside docker. The contents changed on the host machine or inside docker are reflected on both sides. Here is how to use a bind mount. Now if we make changes in this directory…
Hello to all the readers! Docker image is built in layers. Each instruction that is written in Dockerfile translates into an image layer by the builder. When the image is re-built, builder will re-use layers from earlier builds. If any layer is unchanged, then that layer is picked up from the build cache. However, if…