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

This is the fix that worked for me: Ubuntu, Docker version: 1.6.2

In the file /etc/default/docker, add the line:

export http_proxy='http://<host>:<port>'

Restart Docker

sudo service docker restart

Answer 2

Why a locally-bound proxy doesn't work

The Problem

If you're running a locally-bound proxy, e.g. listening on 127.0.0.1:8989, it WON'T WORK in Docker for Mac. From the Docker documentation:

I want to connect from a container to a service on the host

The Mac has a changing IP address (or none if you have no network access). Our current recommendation is to attach an unused IP to the lo0 interface on the Mac; for example: sudo ifconfig lo0 alias 10.200.10.1/24, and make sure that your service is listening on this address or 0.0.0.0 (ie not 127.0.0.1). Then containers can connect to this address.

The similar is for Docker server side. (To understand the server side and client side of Docker, try to run docker version.) And the server side runs on a virtualization layer which has its own localhost. Therefore, it won't connect to the proxy server on the localhost of the host OS.

The solution

So, if you're using a locally-bound proxy like me, basically you would have to do the following things to make it work with Docker for Mac:

1. Make your proxy server listen on 0.0.0.0 instead of 127.0.0.1. Caution: you'll need proper firewall configuration to prevent malicious access to it.

2. Add a loopback alias to the lo0 interface, e.g. 10.200.10.1/24:

   sudo ifconfig lo0 alias 10.200.10.1/24
   

3. Set HTTP and/or HTTPS proxy to 10.200.10.1:8989 from Preferences in Docker tray menu (assume that the proxy server is listening on port 8989).

After that, test the proxy settings by running a command in a new container from an image which is not downloaded:

$ docker rmi -f hello-world
  ...

$ docker run hello-world
Unable to find image 'hello-world:latest' locally
latest: Pulling from library/hello-world

c04b14da8d14: Pull complete 
Digest: sha256:0256e8a36e2070f7bf2d0b0763dbabdd67798512411de4cdcf9431a1feb60fd9
Status: Downloaded newer image for hello-world:latest
  ...

Notice: the loopback alias set by ifconfig does not preserve after a reboot. To make it persistent is another topic. Please check this blog post in Japanese (Google Translate may help).

Answer 3

In the new version of Docker, docker-engine, in a systemd based distribution, you should add the environment variable line to /lib/systemd/system/docker.service, as it is mentioned by others:

Environment="HTTP_PROXY=http://hostname_or_ip:port/"

Answer 4

As I am not allowed to comment yet:

For CentOS 7 I needed to activate the EnvironmentFile within "docker.service" like it is described here: Control and configure Docker with systemd.

Edit: I am adding my solution as stated out by Nilesh. I needed to open "/etc/systemd/system/docker.service" and I had to add within the section

[Service]

EnvironmentFile=-/etc/sysconfig/docker

Only then was the file "etc/sysconfig/docker" loaded on my system.