hostinfo

Simple Go microservice which returns a host info string (name and IP of the host). Accessible via curl, wget, etc. Listens on port 9898 by default, if an int is passed on the command line, that port is used instead. Particularly useful when demonstrating K8s service routing operation (deploy several replicas of this, create a service for the set, then curl the service sequentially to see various hosts respond). The hostinfo service logs inbound requests and the client IP to stdout.

• /python contains a Python version of the service
• /otel contains a Go version of the service that logs in Open Telemetry format

Server Examples

$ ./hostinfo      # listening on port 9898

$ ./hostinfo 80   # listening on port 80

Client Examples

To curl the default port locally:

$ curl localhost:9898
Ming-The-Merciless 192.168.131.12

To wget an instance running on port 80 via a given IP address:

$ wget -O - 10.90.11.43
Doctor-Zarko 10.90.11.43

Kubernetes Example

To curl a k8s service backed by hostinfo instances:

$ kubectl run planetmongo --image rxmllc/hostinfo --port 9898

$ kubectl expose pod planetmongo --port 80 --target-port 9898

Now from another pod:

$ kubectl run -it --rm client rxmllc/tools 

$ curl planetmongo.default.svc.cluster.local

planetmongo 10.90.11.42