[Bug 1084232] Docker fails to pull images from behind a proxy server

[Red Hat Bugzilla]

https://bugzilla.redhat.com/show_bug.cgi?id=1084232

--- Comment #1 from Vincent Batts  ---
you were right to add the HTTP_PROXY to where the docker daemon would use it.
The `docker pull` does not actually fetch bits, but rather instructs the daemon
to fetch the bits.

I'm not sure it is expected behavior for the docker cli to pass HTTP_PROXY to
the daemon for use. This would need to be investigated. If it is the case that
the cli neither uses nor passes HTTP_PROXY, then this is working as intended.
Perhaps there should be verbage in the man-pages for `docker pull` and `docker
run`.