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Docker

Docker logo

Docker is an open platform for developing, shipping, and running applications. Docker enables you to separate your applications from your infrastructure so you can deliver software quickly. With Docker, you can manage your infrastructure in the same ways you manage your applications. By taking advantage of Docker's methodologies for shipping, testing, and deploying code, you can significantly reduce the delay between writing code and running it in production.

The Docker platform

Docker provides the ability to package and run an application in a loosely isolated environment called a container. The isolation and security let you run many containers simultaneously on a given host. Containers are lightweight and contain everything needed to run the application, so you don't need to rely on what's installed on the host. You can share containers while you work, and be sure that everyone you share with gets the same container that works in the same way.

Installing docker

Don't use dnf install docker because this will install podman.

If you had done this then:

# dnf remove docker

The correct way is:

# dnf -y update
# dnf config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
# dnf install docker-ce docker-ce-cli containerd.io
# systemctl enable docker
# systemctl start docker
# systemctl status docker
......
# docker -v
Docker version 29.6.1, build 8900f1d
#

Working with docker images

Docker containers are run from Docker images. By default, it pulls these images from Docker Hub, a Docker registry managed by Docker, the company behind the Docker project. Anybody can build and host their Docker images on Docker Hub, so most applications and Linux distributions you'll need to run Docker containers have images that are hosted on Docker Hub.

The containers are stored in: /var/lib/docker/containers/

Testing docker

Now test docker:

# docker run hello-world
....
# docker run -it ubuntu bash
....
exit
#

When the tests succeeded you can install your containers.

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