How to enable proxy in docker

Sometimes you can encounter issue when pulling images from docker.io or ghcr.io, we can resolve this by add proxy to docker. Here is how what we can do.

1. Find docker.service using:

sudo systemctl status docker

You will see something like this:

● docker.service - Docker Application Container Engine
     Loaded: loaded (/usr/lib/systemd/system/docker.service; enabled; preset: enabled)
     Active: active (running) since Fri 2025-09-19 16:04:46 UTC; 2 months 21 days ago
TriggeredBy: ● docker.socket
       Docs: https://docs.docker.com
   Main PID: 1158 (dockerd)
      Tasks: 154
     Memory: 2.6G (peak: 8.6G)
        CPU: 1h 42min 6.154s
     CGroup: /system.slice/docker.service

You can see the docker.service is running and service file is: /usr/lib/systemd/system/docker.service

2. Edit the docker.service file using your favorite editor
   

vi:
    vi /usr/lib/systemd/system/docker.service

nano:
    nano /usr/lib/systemd/system/docker.service

3. Under the [Service] section, add the following lines:

[Service]
Environment="HTTP_PROXY=http://proxy.example.com:8080/"
Environment="HTTPS_PROXY=https://proxy.example.com:8080/"
Environment="NO_PROXY=localhost,127.0.0.1,docker-registry.example.com"

4. Reload the systemctl daemon using:

sudo systemctl daemon-reload

5. Restart the docker service using:

sudo systemctl restart docker