Docker requires a 64-bit version of CentOS 7 or 8 with a kernel version of 3.10 or higher. While CentOS 7 meets the minimum requirement, its older kernel may lack support for advanced storage drivers like overlay2, potentially leading to reduced performance or instability.

Remove Existing Docker Installations

Older Docker packages may be installed under names like docker or docker-engine. Uninstall them using:

sudo yum remove docker \
docker-client \
docker-client-latest \
docker-common \
docker-latest \
docker-latest-logrotate \
docker-logrotate \
docker-selinux \
docker-engine-selinux \
docker-engine

Install Docker via YUM

Begin by installing the required package management tool:

sudo yum install -y yum-utils

For faster downloads in China, use the Aliyun mirror:

sudo yum-config-manager --add-repo https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
sudo sed -i 's|https://download.docker.com|https://mirrors.aliyun.com/docker-ce|g' /etc/yum.repos.d/docker-ce.repo

If you prefer the official repository, use:

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

To install a testing version, enable the test repository:

sudo yum-config-manager --enable docker-ce-test

Update the package index and install Docker:

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

Automated Installation Script

Docker provides a one-line installer for quick setup in development environments. To use the Aliyun mirror:

curl -fsSL https://get.docker.com -o install-docker.sh
sudo sh install-docker.sh --mirror Aliyun

For Azure China Cloud users:

sudo sh install-docker.sh --mirror AzureChinaCloud

The script automatically configures repositories, installs the latest stable version, and starts the service.

Additional Configuration for CentOS 8

CentOS 8 uses nftables as the default firewall back end, which is not fully compatible with Docker. To resolve this, switch to iptables:

Option 1: Edit the fierwall configuration file:

sudo sed -i 's/#FirewallBackend=nftables/FirewallBackend=iptables/' /etc/firewalld/firewalld.conf

Option 2: Allow Docker’s bridge interface directly:

sudo firewall-cmd --permanent --zone=trusted --add-interface=docker0
sudo firewall-cmd --reload

Start and Enable Docker

sudo systemctl enable --now docker

Create the Docker User Group

By default, Docker requires root privileges to interact with its daemon via Unix socket. To avoid running Docker commands as root, create a dedicated group and add your user to it:

sudo groupadd docker
sudo usermod -aG docker $USER

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

Verify Installation

Run the following command to confirm Docker is working correctly:

docker run hello-world

If you see a welcome message and container execution output, Docker is successfully installed and configured.