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Docker CE Installation on CentOS

This guide walks you through installing and configuring Docker Community Edition (CE) on a CentOS-based system. It covers repository setup, installation, post-installation steps, and troubleshooting common permission errors.

Table of Contents

Prerequisites

  • A CentOS or RHEL-based system (CentOS 7/8, RHEL 7/8).
  • sudo privileges or root access.
  • Internet connectivity to download packages.

Installation Steps

1. Enable EPEL Repository

sudo yum install -y epel-release

The EPEL (Extra Packages for Enterprise Linux) repository provides additional packages required by Docker CE.

2. Remove Older Docker Versions

sudo yum remove -y docker docker-common docker-selinux docker-engine

This ensures no conflicts with previous installations.

3. Set Up Docker Repository

Install required utilities and configure the Docker CE repository:

sudo yum install -y yum-utils device-mapper-persistent-data lvm2
sudo yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo

4. Install Docker CE

sudo yum install -y docker-ce docker-ce-cli containerd.io

5. Start and Enable Docker Service

sudo systemctl start docker
sudo systemctl enable docker

Verify Docker is running:

docker version

Post-Installation Configuration

Manage Docker as a Non-Root User

  1. Create the docker group (if it doesn't exist):
sudo groupadd docker
  1. Add your user to the docker group:
sudo usermod -aG docker $USER

  1. Log out and log back in for group changes to take effect.

  2. Verify you can run Docker without sudo:

docker run hello-world

Uninstallation

To remove Docker CE and related data completely:

sudo yum remove -y docker-ce docker-ce-cli containerd.io
sudo rm -rf /var/lib/docker
sudo rm -rf /var/lib/containerd

Troubleshooting

Permission Denied on Docker Config File

If you encounter:

Error loading config file: /home/user/.docker/config.json: permission denied

Fix with:

sudo chown "$USER":"$USER" "/home/$USER/.docker" -R
sudo chmod g+rwx "/home/$USER/.docker" -R

Permission Denied Connecting to Docker Daemon

Error:

Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: connect: permission denied

Resolve by adding your user to the docker group (see above) and restarting your session.

References

  • Official Docker CE Documentation: https://docs.docker.com/engine/install/centos/