如何从GitHub拉取Docker镜像并在EC2实例中构建镜像？

Hey there! Let's break down exactly how to pull a Docker image hosted on GitHub. First, a quick heads-up: GitHub stores container images in their GitHub Container Registry (GHCR)—so that's the registry we'll be interacting with here. Here's your step-by-step guide tailored for your EC2 instance:

• Step 1: Confirm Docker is installed on your EC2 instance
  First, check if Docker is up and running with this command:

  docker --version
  

  If it's not installed, use your EC2's package manager to set it up:

  • For Amazon Linux: sudo yum install docker -y
  • For Ubuntu: sudo apt install docker.io -y
    Don't forget to start and enable the Docker service so it runs on boot:

  sudo systemctl start docker
  sudo systemctl enable docker
  

• Step 2: Find your image's GHCR path
  GitHub container images follow this standard format:

  ghcr.io/<your-github-username>/<image-repo-name>:<tag>
  

  For example, if your GitHub username is krish0033 and your image repo is my-web-app tagged latest, the full path would be ghcr.io/krish0033/my-web-app:latest. You can grab this path by visiting your GitHub repo's Packages tab (look in the repo sidebar under "Packages") or checking the repo's README if the image is documented there.

• Step 3: Log into GHCR (only for private images)
  If the image is private, you'll need to authenticate with a GitHub Personal Access Token (PAT). First, create a PAT in your GitHub account settings with the read:packages permission (this is the only permission needed for pulling private images). Then run this command on your EC2 instance to log in securely:

  echo "<your-github-pat>" | docker login ghcr.io -u <your-github-username> --password-stdin
  

  Using --password-stdin keeps your PAT out of your shell history, which is way safer than typing it directly.

• Step 4: Pull the image
  Now run the pull command with your image's full GHCR path:

  docker pull ghcr.io/<your-github-username>/<image-repo-name>:<tag>
  

  If you're pulling the latest tag, you can skip the :latest part—Docker will default to it automatically:

  docker pull ghcr.io/<your-github-username>/<image-repo-name>
  

• Step 5: Verify the pull worked
  Check your local Docker images to confirm the image is now on your EC2 instance:

  docker images
  

  You should see your GitHub-hosted image listed in the output.

Quick Tips #

• Public images: No login required! Just run the docker pull command directly.
• PAT security: On EC2, avoid hardcoding your PAT in scripts. Store it in AWS Secrets Manager and retrieve it programmatically, or use a temporary environment variable that doesn't get saved.

内容的提问来源于stack exchange，提问作者krish0033