HI All,

Using `kolla-build -b ubuntu` to build container images keeps timing
out (well hanging for literal days) seemingly on package downloads
from remote mirrors.

I'm new to kolla and kolla-ansible so I may be misdiagnosing the cause
of my current issue but we de have local ubuntu package mirros which
would be faster in any case. Is there a way to specify using only a
local package mirror?

Thanks,
-Jon