Propagation of external service IPs to pods

[jeinwag]

Currently, internal service IP addresses (portals) are propagated to pods via environment variables (MY_SERVICE_HOST etc).

Should there be a similar mechanism for external portals (which are created by specifying publicIPs in the service spec)?

[thockin]

To where would we propagate them? No point in exposing them to pods, since they already have internal IPs...

[jeinwag]

I was indeed thinking of the pods, since there might be situations where a service needs to know its public IP address.

[bgrant0607]

This is a special case of #386, and is related to #560.

Making a service IP known to pods targeted by it is most compelling for nominal services (#260), but I could see it being useful for other cases, also.

We've decided that environment variables are not going to be the mechanism for communicating this type of data -- instead we'll use (pseudo) files and/or HTTP.

[bgrant0607]

Or, we could make the service look like some kind of network alias or somesuch.

[brendandburns]

Updated #386 to include a reference to this bug, closing this as a dupe of that issue.