Docker Proxy Configuration: Container Networking Guide

Docker Proxy Setup

Configure proxies for Docker containers in various scenarios.

TL;DR: Set HTTP_PROXY environment variables in containers. Configure daemon for build-time proxy.

Container Runtime Proxy

docker run -e HTTP_PROXY=http://proxy:port \
           -e HTTPS_PROXY=http://proxy:port \
           my-image

Dockerfile

ARG HTTP_PROXY
ARG HTTPS_PROXY

RUN apt-get update && apt-get install -y something

Build with:

docker build --build-arg HTTP_PROXY=http://proxy:port .

Docker Compose

services:
  app:
    environment:
      - HTTP_PROXY=http://proxy:port
      - HTTPS_PROXY=http://proxy:port

Docker Daemon Config

For system-wide proxy, edit /etc/docker/daemon.json:

{
  "proxies": {
    "http-proxy": "http://proxy:port",
    "https-proxy": "http://proxy:port"
  }
}

Best Practices

1. Don't bake credentials in images
2. Use build args for build-time
3. Use env vars for runtime
4. Consider secrets management