Docker : cannot access internet from container

Question

I am running CentOS 6.6 behind a corporate proxy. I've installed docker, and I had to make some modifications in order for the daemon to access the Docker Hub through the proxy. This part is working fine.

# /etc/sysconfig/docker
HTTP_PROXY='http://domain\username:password@proxy:port'
HTTPS_PROXY='https://domain\username:password@proxy:port'
export HTTP_PROXY HTTPS_PROXY

My problem is that my containers seems like they can't access the internet (apt-get update times out, can't get the user-guide web app to work, ...).

I have sysctl -w net.ipv4.ip_forward=1on both host and containers.

I've tried multiple things I've found with a google research, but without success :

• adding option -p :80 in order to redirect HTTP requests through the host
• adding option --net=host
• adding --dns 8.8.8.8 --dns 8.8.4.4 (I'm not even able to ping the dns servers when doing this)
• setting http_proxy and https_proxy variables in the containers

If you need me to post some output I'll be glad to do it.

Answer 1

I've solved the problem, and it wasn't at all related to Docker. It was just a proxy problem.

I was testing by running an ubuntu:14.10 container, and by running apt-get update, which wasn't working.

The solution was to edit the /etc/apt/apt.conf file in the container to add the proxy information. After that, apt-get update was working like a charm.