Cannot download Docker images behind a proxy

Question

I installed Docker on my Ubuntu 13.10 (Saucy Salamander) and when I type in my console:

sudo docker pull busybox

I get the following error:

Pulling repository busybox
2014/04/16 09:37:07 Get https://index.docker.io/v1/repositories/busybox/images: dial tcp: lookup index.docker.io on 127.0.1.1:53: no answer from server

Docker version:

$ sudo docker version

Client version: 0.10.0
Client API version: 1.10
Go version (client): go1.2.1
Git commit (client): dc9c28f
Server version: 0.10.0
Server API version: 1.10
Git commit (server): dc9c28f
Go version (server): go1.2.1
Last stable version: 0.10.0

I am behind a proxy server with no authentication, and this is my /etc/apt/apt.conf file:

Acquire::http::proxy "http://192.168.1.1:3128/";
Acquire::https::proxy "https://192.168.1.1:3128/";
Acquire::ftp::proxy "ftp://192.168.1.1:3128/";
Acquire::socks::proxy "socks://192.168.1.1:3128/";

What am I doing wrong?

Answer 1

Here is a link to the official Docker documentation for proxy HTTP: https://docs.docker.com/config/daemon/systemd/#httphttps-proxy

A quick outline:

First, create a systemd drop-in directory for the Docker service:

mkdir /etc/systemd/system/docker.service.d

Now create a file called /etc/systemd/system/docker.service.d/http-proxy.conf that adds the HTTP_PROXY and HTTPS_PROXY environment variables:

[Service]
Environment="HTTP_PROXY=http://proxy.example.com:80/"
Environment="HTTPS_PROXY=http://proxy.example.com:80/"

If you have internal Docker registries that you need to contact without proxying you can specify them via the NO_PROXY environment variable:

Environment="HTTP_PROXY=http://proxy.example.com:80/"
Environment="HTTPS_PROXY=http://proxy.example.com:80/"
Environment="NO_PROXY=localhost,127.0.0.0/8,docker-registry.somecorporation.com"

Flush changes:

$ sudo systemctl daemon-reload

Verify that the configuration has been loaded:

$ sudo systemctl show --property Environment docker
Environment=HTTP_PROXY=http://proxy.example.com:80/
Environment=HTTPS_PROXY=http://proxy.example.com:80/

Restart Docker:

$ sudo systemctl restart docker

---

Footnote regarding HTTP_PROXY vs. HTTPS_PROXY: for a long time, setting HTTP_PROXY alone has been good enough. But with version 20.10.8, Docker has moved on to Go 1.16, which changes the semantics of this variable: https://golang.org/doc/go1.16#net/http
For https:// URLs, the proxy is now determined by the HTTPS_PROXY variable, with no fallback on HTTP_PROXY.