support for private subnets

[justinsb]

kops needs the capability to create subnets which are both public and private. This should do three things:

1. Create an ASG spread across the private subnets
2. Create an ASG on the public subnets (with EIPs ideally)
3. Label the instances distinctly between the ASGs (external / internal or similar)

(migrated from kubernetes-retired/kube-deploy#157)

[ProTip]

We need private subnets to meet our security obligations.

[ProTip]

@justinsb Is there something we can do to help expedite this? I can help with implementation if I had an idea of where to start. Might worth considering #232 at the same time?

[billyshambrook]

Hey @justinsb, would you be able to expand on point 3 and what the labels would need to be for kubernetes to work?

I am happy to contribute with this feature.

[chrislovecnm]

@billyshambrook please reach out, we are having a planning meeting, and would love your help!!

@kris-nova How does this fold into #428

[krisnova]

Finished with #428