How to Create a Docker Image from a Container

How to Create a Docker Image from a Container

Creating a Docker image from a running container

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2 min read

Docker is a powerful tool that simplifies the process of deploying applications in a consistent and reproducible environment. One of the common tasks when working with Docker is creating a Docker image from a running container. This guide will walk you through the steps to achieve this, ensuring that you can save your container state as an image for future use. Let's dive into the process.

Step 1: SSH into the Host:

First, you need to access the host machine where your Docker container is running. This is typically done using SSH (Secure Shell). Follow the command below to SSH into your host:

ssh user@hostname

Replace user with your username and hostname with the address of your host machine. This command will prompt you for a password or use an SSH key, depending on your setup.

Step 2: Run the Docker Commit Command:

Once you are logged into the host machine, the next step is to create a Docker image from your running container. This is done using the docker commit command. The docker commit command saves the state of a container as a new image.

docker commit -a "Developer" ubuntu_latest ecommerce:xfusion

Here's a breakdown of the command:

  • -a "Developer": This option allows you to specify the author of the image.

  • ubuntu_latest: This is the name (or ID) of the container you want to commit.

  • ecommerce:xfusion: This is the name and tag you want to give to the new image

By running this command, Docker will create a new image named ecommerce with the tag xfusion from the ubuntu_latest container.

Step 3: Verify the New Image:

docker image ls

This command will display a list of all available Docker images along with their tags, sizes, and creation dates. Look for the ecommerce:xfusion image in the list to confirm that it was created successfully.

Conclusion

Creating a Docker image from a running container is a straightforward process that involves three main steps: SSH into the host, run the Docker commit command, and verify the new image. By following these steps, you can easily save the state of your containers and use the images for future deployments.

Docker's ability to commit containers to images is particularly useful for development and testing environments, where you might need to save your progress and ensure consistency across different stages of your workflow. Happy Dockerizing!