Docker运行hello-world超时报错求助：Pop!_OS 19.04环境下无法拉取镜像

Hey there! Let's work through this Docker connection issue you're facing—since you're just starting out with Django and Docker, I know this roadblock can feel pretty frustrating. Let's go through practical steps to get that hello-world image running smoothly.

1. Check Network & DNS Settings #

The error points to a timeout connecting to Docker Hub, so first let's rule out DNS-related issues:

• Test if you can reach Docker Hub's registry with this command:

  ping registry-1.docker.io
  

  If this fails (no response), your system's DNS is probably misconfigured.
• Update your DNS to use public, reliable servers like Google's or Cloudflare's:
  • For systems using systemd-resolved (common in Pop!_OS), edit /etc/systemd/resolved.conf and set:

    DNS=8.8.8.8 1.1.1.1
    

  • Save the file, then restart the service to apply changes:

    sudo systemctl restart systemd-resolved
    

  • Alternatively, temporarily edit /etc/resolv.conf to add nameserver 8.8.8.8 (note: this change might be overwritten on reboot, so the systemd-resolved method is more permanent).

2. Use Domestic Docker Registry Mirrors #

Accessing Docker Hub directly from some regions can be slow or unreliable. Configuring domestic mirrors will speed up image pulls significantly:

• Create or edit the Docker daemon config file:

  sudo nano /etc/docker/daemon.json
  

• Paste this content (using popular, stable Chinese mirrors):

  {
    "registry-mirrors": [
      "https://hub-mirror.c.163.com",
      "https://mirror.baidubce.com"
    ]
  }
  

• Save the file, then reload and restart Docker to apply the mirror settings:

  sudo systemctl daemon-reload
  sudo systemctl restart docker
  

• Now try running the hello-world command again:

  sudo docker run hello-world
  

3. Check Proxy & Firewall Settings #

If you're behind a proxy or firewall, Docker might not be using the correct network configuration:

• Proxy Configuration:
  • Create a proxy config file for Docker:

    sudo nano /etc/systemd/system/docker.service.d/http-proxy.conf
    

  • Replace your-proxy-address:port with your actual proxy details, then paste:

    [Service]
    Environment="HTTP_PROXY=http://your-proxy-address:port/"
    Environment="HTTPS_PROXY=http://your-proxy-address:port/"
    Environment="NO_PROXY=localhost,127.0.0.1"
    

  • Reload and restart Docker to apply the proxy settings:

    sudo systemctl daemon-reload
    sudo systemctl restart docker
    

• Firewall Check:
  • Temporarily disable your firewall (like ufw) to test if it's blocking connections:

    sudo ufw disable
    

  • If the hello-world command works after this, re-enable the firewall and add a rule to allow Docker traffic:

    sudo ufw enable
    sudo ufw allow docker
    

4. Verify Docker Version Compatibility #

Pop!_OS 19.04 (based on Ubuntu 19.04, codenamed disco) is an older release, and newer Docker versions might have compatibility issues. Try installing a Docker version confirmed to work with this release:

• Uninstall your current Docker installation completely:

  sudo apt-get purge docker-ce docker-ce-cli containerd.io
  sudo rm -rf /var/lib/docker
  

• Install a compatible version (19.03.x is known to work well with Ubuntu 19.04):

  sudo apt-get install docker-ce=5:19.03.15~3-0~ubuntu-disco docker-ce-cli=5:19.03.15~3-0~ubuntu-disco containerd.io
  

• Start Docker and test the hello-world command again:

  sudo systemctl start docker
  sudo docker run hello-world
  

Give these steps a try one by one—most of the time, the DNS or mirror source fix resolves this issue quickly. Once you get that hello-world container running, you'll be all set to start working on your Django project with Docker!

内容的提问来源于stack exchange，提问作者Bobkatabo