hello-from
is a simple HTTP service that responds with its hostname and the non-loopback IPv4 addresses of its environment. Its main use is for demoing load-balancing applications, like Kubernetes Services.
Example:
$ docker run -ti -p 80:80 -d --name=hello-from pbitty/hello-from
498ca7cb25e92c2c0152ea5993b91cef2b0a35de7a7dc6fbfefd21194301190b
$ curl 192.168.99.102
Hello from 498ca7cb25e9 (172.17.0.2)