Comment 4 for bug 1829586

@Mark

Sorry for being late. Here is my initial thought to implement

1. Add new variable to 'all.yml' http(s)_proxy
2. Use the variable when defined at 'bootstrap-servers' stage for git, apt, pip modules.

This is quite similar to other deployment system (https://github.com/kubernetes-sigs/kubespray/blob/master/roles/bootstrap-os/tasks/bootstrap-debian.yml)

And the drawbacks of this compared to adding ENVIRONMENT variable for each modules are obviously that it affect the deployed node itself. However from my current understanding, there is no way to apply http_proxy variable some programs (dockerd, apt...) via shell environment and it's difficult to depend the shell variables since each programs has their own implementation about "http_proxy"

Please give me your thought about it.

Thanks