Comment 1 for bug 1703698

@hongbin, I'm trying to re-produce this problem.

while use latest devstack-plugin-container install docker, I get the follwoing error:
root@devstack:/vagrant# uname -a
Linux devstack 4.4.0-77-generic #98-Ubuntu SMP Wed Apr 26 08:34:02 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
root@devstack:/vagrant# curl -fsSL https://download.docker.com/linux/ubuntu/gpg
curl: (6) Could not resolve host: download.docker.com

Looks like I get similar problem with:
http://www.ttlsa.com/linux/curl-6-couldnt-resolve-host/

When I add '-4' it works for me(use ipv4):
root@devstack:/vagrant# curl -fsSL4 https://download.docker.com/linux/ubuntu/gpg

Did you get same problem before?
my vm is using : ubuntu/xenial64 20170503.1.0

Thanks, I will skip this problem manually to go on research your problem this week.