Install Docker on CentOS

 Installing Docker 

Confirm Packages are Installed

1. Install the packages:
 sudo yum install -y yum-utils lvm2 device-mapper-persistent-data

2. Alternatively, if the packages are likely installed, the following command can be used to verify the installation without installing the package if one is missing. Each of these commands must be run and verified individually:
 rpm -qa |grep yum-utils
 rpm -qa |grep lvm2
 rpm -qa |grep device-mapper-persistent-data

Add the Repository

1. Add the repository:        

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

2. Confirm the repository has been added by checking the repo directory:

 ls /etc/yum.repos.d/

Install Docker

1. Install Docker:

 sudo yum install docker-ce

Enable and Start Docker

1. Enable Docker:

 sudo systemctl enable docker

2. Start Docker:

 sudo systemctl start docker

Add Your User to the Docker Group

1. Add your user to the Docker group:

 sudo usermod -a -G docker cloud_user

2. Verify the addition:

 grep docker /etc/group

3. Log out of the system and back in to confirm the changes.

Create Your First Container

1. Create the hello-world container:

 sudo docker run hello-world