Previous Docker tutorial we have learned how to install docker service and build the container. I recommend you to read my first article about docker before continuing with this article
Part1: Docker installation and configuration
Part2: How to create an image from the container
Part3: Dockerfile: To automate Docker image creation
In this article, we will discuss how to create a new image from the container. In my first post, we have created a container named “lampstack” from the image Ubuntu. Here we will create a new image from the container “lampstack” so we can use it for the future.
The Docker flow:
Our lampstack container installed with the packages Apache2, MySQL and PHP, so converting this container to an image will help in the future.
Steps to convert container to an image
Check the status of the docker by issuing the following command
#docker ps -a
Here we can see our “lampstack” container is running. We will convert this container to an image for this, stop this container by issuing the following command
#docker stop container
and then run docker commit command as follows.
ubuntu: lampstack: Image name as Ubuntu and tag name is lampstack
cf377947975e : Container ID
Now we have created a new image, we can list it by running command “docker images”
From the above screenshot, we can see our new image ubuntu with tag “lampstack” is created 7 minutes ago.
To test the working of the new image we will run a new container from it
Here we created a new container named “newlampstack” from the image ubuntu:lampstack.
To use our new image in the future or if we want to deploy it in any other machine, first we have to publish it on a registry. There are many different registries you can use. Here I am using the Docker hub registry.
Docker Hub Registry
Docker hub is a public image registry service in which you can publish your images, test them and you can deploy it to any host. To publish in the docker hub you should create an account on Dockerhub. Once you registered in the docker hub then you can proceed with publishing your image.
First, log in to the registry by issuing the command
Provide the same credentials that you used for logging into Docker Hub.
and then tag your image name same as newly created repo name (create it at the docker hub)
#docker tag 1452cfe9e4ff rinshadr/ubuntu:lampstack
1452cfe9e4ff: Image ID
rinshadr/ubuntu: my repo name created in docker hub
Then push the image with docker push command. The format should be repo name/image name.
# docker push rinshadr/ubuntu:lampstack
We have created our image and pushed it to the DockerHub public registry.
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