Docker is a powerful platform for building, shipping, and running distributed applications. It allows developers to package up an application with all of the parts it needs, such as libraries and other dependencies, and ship it out as one package. This makes it easy to run the application on any machine, regardless of whether or not the dependencies are already installed.

In this guide, we’ll go over how to install Docker on a CentOS machine. We’ll start by going over some prerequisites and then move on to the actual installation process.

Prerequisites

Before we get started with the installation process, there are a few things you’ll need to have in place. First, you’ll need to have a machine running CentOS. If you don’t have one, you can easily set one up using a virtual machine or by installing CentOS on a physical machine.

The second thing you’ll need is root access to the machine. If you’re using a virtual machine, you can usually gain root access by logging in as the administrator. If you’re using a physical machine, you’ll need to have the root password.

Finally, you’ll need to have the yum package manager installed on your machine. Yum is a package manager for CentOS that makes it easy to install and manage software on your machine. If you don’t have it installed, you can easily install it by running the following command:

sudo yum install -y yum

Installing Docker

Now that we have all of the prerequisites in place, we can move on to the actual installation process. The first step is to add the Docker repository to your machine. This will allow you to easily install and update Docker in the future. To add the repository, run the following command:

sudo yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo

Once the repository has been added, you can install Docker by running the following command:

sudo yum install docker-ce

This command will install the latest version of Docker. If you want to install a specific version, you can specify it in the command. For example, to install version 20.10.5, you would run the following command:

sudo yum install docker-ce-20.10.5

Once the installation is complete, you’ll need to start the Docker service. You can do this by running the following command:

sudo systemctl start docker

You can also enable Docker to start automatically on boot by running the following command:

sudo systemctl enable docker

Using Docker

Now that Docker is installed, you can start using it to build, ship, and run your applications. One of the first things you’ll probably want to do is run the “Hello World” container. This is a simple container that will display the message “Hello from Docker” when you run it. To run the container, you’ll use the “docker run” command. The syntax for the command is as follows:

docker run [options] [image] [command]

To run the “Hello World” container, you’ll use the following command:

docker run hello-world

This command will download the “hello-world” image and then run it. Once the container is running, you should see the “output “Hello from Docker!” displayed on the screen.

Another common task you might want to do is pull an image from a remote repository, such as Docker Hub. Docker Hub is a public repository of Docker images that you can use to easily find and download images for your applications. To pull an image from Docker Hub, you’ll use the “docker pull” command. The syntax for the command is as follows:

docker pull [image]

For example, to pull the latest version of the nginx image, you would run the following command:

docker pull nginx

Once you have the image downloaded, you can run it using the “docker run” command. To run the nginx image, for example, you would use the following command:

docker run -d -p 80:80 nginx

This command will run the nginx image in detached mode, which means it will run in the background. It also maps port 80 on the host to port 80 in the container, which will allow you to access the nginx web server from your host machine.

You can also use the “docker ps” command to see a list of all running containers and their status. Additionally, you can use the “docker stop” command to stop a running container and the “docker rm” command to remove a stopped container.

Conclusion

Installing Docker on CentOS is a simple process that can be completed in just a few steps. Once you have Docker installed, you’ll be able to easily build, ship, and run your applications on your machine. Whether you’re a developer looking to test your application or an administrator looking to deploy it to production, Docker makes it easy to get your application up and running quickly. With this guide, you should be able to get started with Docker on your CentOS machine in no time.