Install Docker on Ubuntu

• Enviroment: Ubuntu=24.4

Firewall limitations

1. If using ufw or firewalld to manage firewall settings,

   When you expose container ports using Docker, these ports bypass your firewall rules.

2. Docker is only compatible with iptables-nft and iptables-legacy.

   Firewall rules created with nft are not supported on a system with Docker installed.
   Make sure that any firewall rulesets you use are created with iptables or ip6tables, and that you add them to the DOCKER-USER chain.

Uninstall Docker（old versions）

1. Uninstall the Docker Engine, CLI, containerd, and Docker Compose packages:

   sudo apt-get purge docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin docker-ce-rootless-extras

2. Remove all images, containers, and volumes:

   sudo rm -rf /var/lib/docker
   sudo rm -rf /var/lib/containerd

3. Remove source list and keyrings

   sudo rm /etc/apt/sources.list.d/docker.list
   sudo rm /etc/apt/keyrings/docker.asc

Installation

Switch apt sources

1. Backup source list

   sudo cp /etc/apt/sources.list.d/ubuntu.sources /etc/apt/sources.list.d/ubuntu.sources.bak

2. Find out sources
   Here I use Tsinghua mirror

3. Modify the source

   sudo vi /etc/apt/sources.list.d/ubuntu.sources

4. Update

   sudo apt-get update
   sudo apt-get upgrade

Install using the apt repository

1. Set up the Docker apt repository

   # Add Docker's official GPG key:
   sudo apt-get install ca-certificates curl
   sudo install -m 0755 -d /etc/apt/keyrings
   sudo curl -fsSL https://download.docker.com/linux/ubuntu/gpg -o /etc/apt/keyrings/docker.asc
   sudo chmod a+r /etc/apt/keyrings/docker.asc
   
   # Add the repository to Apt sources:
   echo \
   "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] https://download.docker.com/linux/ubuntu \
   $(. /etc/os-release && echo "$VERSION_CODENAME") stable" | \
   sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
   sudo apt-get update

2. Install the Docker packages

   sudo apt-get install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin

3. Verify that the installation is successful

   Check docker command:

   sudo docker image ls
   # REPOSITORY  TAG  IMAGE  ID  CREATED  SIZE

   OR running the hello-world image:

   sudo docker run hello-world

   The later one may issue error for two reason:

   1. Run without sudo: The docker user group exists but contains no users, which is why you’re required to use sudo to run Docker commands.

   2. Can not access to Docker Hub: The image ‘hello-world’ is not exist locally, it requires to get access to Docker Hub to download the image.

Reference

https://docs.docker.com/engine/install/ubuntu/
https://www.cnblogs.com/lcxhk/p/14951334.html