Docker Inside Docker : Advantages

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Hope this blog finds you great and healthy !!😊

Lets begin with brief introduction about me…..

Hi, This is Ankit Shukla and I am working as SDET Automation/functional Engineer in Regulatory Reporting Domain. In this article we will discuss about How To install docker inside docker?

Why Install Docker Inside Docker?

Before diving into the installation process, let’s briefly understand why you might want to run Docker inside Docker:

1. Isolated Environments: Docker-in-Docker enables you to create isolated environments within your host Docker environment. This can be useful for testing or experimenting with different Docker configurations without affecting the host system.
2. CI/CD Pipelines: In Continuous Integration/Continuous Deployment (CI/CD) pipelines, Docker-in-Docker can be employed to build and test Docker images inside a temporary container, ensuring consistency across multiple stages of the pipeline.
3. Multi-tenancy: If you’re running a multi-tenant environment or need to provide Docker capabilities to different users with controlled access, Docker-in-Docker can serve as an isolated sandbox for each user.

Step-by-Step Guide to Install Docker Inside Docker

Let’s follow the below process of setting up Docker inside Docker:

Step 1: Set Up the Host Environment

Please make sure that you have Docker installed on your host system(Base). If you don’t have Docker installed, you can follow the official Docker documentation to install it for your specific operating system.

For windows : https://docs.docker.com/desktop/install/windows-install/

For Linux : https://docs.docker.com/engine/install/ubuntu/

Step 2: Pull the Docker Image

To run Docker inside Docker, you’ll need the appropriate Docker image that supports this functionality. One commonly used image is docker:dind (Docker-in-Docker).

Pull the image using the following command:

docker pull docker:dind

Step 3: Run Docker-in-Docker Container

Now, you can run the Docker-in-Docker container by executing the following command:

docker run — privileged — name docker-in-docker -d docker:dind

The --privileged flag is necessary to allow the inner Docker container to have the required privileges for running Docker commands.

Step 4: Accessing the Nested Docker

To access the Docker running inside the container, you can execute a shell inside the container using the following command:

docker exec -it docker-in-docker sh

Now you are inside the nested Docker environment, and you can run Docker commands as usual.

Try to explore with commands used inside container

Important Note: Running Docker inside Docker can be a powerful tool, but it comes with certain security risks. It is essential to use this setup carefully and avoid exposing the Docker socket from the nested container to the host or other untrusted environments.

Running Docker inside Docker can be a valuable addition to your container toolkit, allowing you to create isolated environments and streamline CI/CD pipelines. With the steps provided in this article, you can set up Docker-in-Docker on your host system and explore its various use cases. Remember to exercise caution and best security practices when using this setup, and enjoy experimenting with nested container environments!

Thank you so much for reading the article….Please share any feedback/suggestion…🙂