First, let met just say I don’t think this is a problem that “first world” users are likely to experience.
Our situation is as follows:
- Private docker registry hosted on site, behind SSL terminating haProxy
- docker swarm with overlay network running in two geographically separate data centers.
- Swarm is not large: 7 hosts at present count
- Attempt at a microservice architected app, 7 distinct containers at present count
We ARE currently having connectivity issues, but generally we are not considered one of the best broadband areas in any case.
What I could see by monitoring traffic on the private registry host is upload speeds of about 40kb. Which is rather sad and pathetic, but it is what it is.
So with 7 hosts trying to download the same image concurrently - you can imagine. It took me about 6 hours, with a whole bunch of restarts to get things running.
If I get the time, I will try an experiment with only one host downloading.
PS: related but separate - it might help if docker-compose could provide slightly more output when (for example) pulling images. Currently you get
xxxxxxxxxxx: Pulling repo.somehost.xx.aa/someapp-web:0.0.2...
which is fun for the first 5 minutes, but after 30 you start to wonder.