boot2docker/boot2docker — pull request #411 by fayep (2014-06-28 06:16:09+00:00)
Title: #357 Wait for eth0 to be up before starting docker - borrow existing code

Took code from tc-config which waits for dhcp to complete. This version doesn't ping, but you could ping the DNS server (10.0.2.3) which I think only exists if you have nat dns host resolver enabled or 10.0.2.2 (does that always exist?)
This, tied with a change in boot2docker-cli which would create the VM with the nat dns host resolver (that I haven't yet codified) will make sure dns for containers is the same as the host dns. I tested this manually :(