Proposal: Provide public IP and/or domain name to the container via env var

[capoferro]

(Extracted from thread in #7421)

For apps that register themselves with service discovery (such as Eureka), containers need to know what their publicly accessible IP or domain name is in order for the contained apps to register themselves correctly.

[thaJeztah]

Hm, curl http://bot.whatismyipaddress.com 😄

[capoferro]

lol, "publicly" may not mean "visible from the internet" 🐹

Perhaps there is a better word for the IP address that other boxes can connect to...

[thaJeztah]

I know 😀 was just kidding around.

Wasn't there a generic issue regarding an improved "introspection" API from within the container somewhere? Maybe issues like this should be collected / linked in a single "wrapper" issue

[capoferro]

@thaJeztah There are some notes on introspection in these threads: #7255 and #4332.

[cpuguy83]

WIP but check out: https://github.com/cpuguy83/lestrade

Unfortunately it has to be run on the host and not in the container due to issues picking up newly created containers.

[flaviostutz]

+1
I really need this for registering container services on etcd from inside the container!
For example, if I have a bunch of NodeJS containers serving my Application (with elastic resizing) and I have a bunch of NGinx containers on its front balancing requests, I would like to have NGinx instances to lookup at etcd for available NodeJS containers (along with IP:port) so that NGinx instances could automatically reconfigure themselves for added/removed NodeJS containers during operations.

[thaJeztah]

@flaviostutz I wonder if that should be done by the container itself, or by a separate container, making use of docker events; ie, when a container is started, docker fires a "start" event. The separate container listens for these events and registers the container in etcd.

A nice blog post (using docker-gen), can be found here: Docker Service Discovery Using Etcd and Haproxy. If you just need to configure NGINX, also have a look at nginx-proxy

I'm not sure if those example cover your needs, but they may give you some ideas.

HTH!

[cpuguy83]

Or you can even have nginx use etcd as a source of routing... this would require some LUA stuff, though I wouldn't be surprised if someone has done this.
There is also hipache (and nginx-hipache) which uses redis as a backend.

[vdemeester]

Given the activity level on this issue, I'm going to close it as it's either fixed, a duplicate or not a request anymore. If you think I'm mistaken, feel free to discuss it there 😉

[dmick]

"I don't know the status of this issue so I'll close it"

[capoferro]

@dmick It's honestly reasonable to close an issue that hasn't seen activity in 3 years.