How To Create a Docker Image, Build and Push It To Docker Hub
This is a simple explanation of the Docker workflow. From creating the first Dockerfile to pushing it to Docker.
without going into any details, this simply describes the workflow when creating a Docker image and all code that is necessary to know.
1. Create a Dockerfile in the root directory, modify it
This is an example of a simple
node application. Nothing I will get into now. This is just about the workflow.
Create the file with
FROM node:10 WORKDIR /usr/src/app COPY package*.json ./ RUN npm install COPY . . EXPOSE 8080 CMD [ "node", "server.js" ]
You can also include a
.dockerignore file to prevent local modules to be copied into Docker.
2. Build the image
Based on the
Dockerfile, we can build an image with the following command. We need to include the username so that we can push it to Docker Hub later.
docker build -t <username>/<image-name>:<tag> .
.- means the current working directory, will use the dockerfile in that directory.
-t- will add a tag to the image
image-name- the name of the image
tag- the tag of the image your creating,
Other important build flags
Some other flags you might use when building a Docker image.
-f, --file- path to Dockerfile if another name or in another directory
--no-cache- force rebuild without using cache
--rm- remove intermediate containers after build
3. Run the Docker container
You can run the container (based on the image we created) locally with the following command.
docker run -d -p 49160:8080 <image-name>:<tag>
-d- means detached, it will happen in the background.
-p- specifies which port to use. In this case
8080within the container.
Other important run flags
--name- set a name to the container
--rm- remove container when it exists
If you want to enter the container, you can use the
exec command. You will need to use the container id which you can get by writing
docker exec -it <container-id> /bin/bash
4. Push the Docker container to Docker Hub
Finally, you can push the image to Docker Hub to share it.
docker push <username>/<image-name>