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.

Solution

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.

Comments

[jackdh]

Thank you this saved me a load of trouble. For others: the proxies need to be formatted like in this answer. askubuntu.com/a/342180/313830