showReadiness

A simple golang application to explore liveness and readiness checks in Kubernetes.

Explanation

The showreadiness program will respond to requests on port 80 locally, port 6080 externally, with text indicating it is handling traffic. With that response, there is a header called responding-pod which contains the name of the pod (its hostname).

Calling /makeNotReady will disable traffic processing for whichever host handled the request. Using this endpoint, we can stop traffic to each pod, and then restore it using the /makeReady endpoint directly (via accessing the pod over localhost).

To build

In the cloned directory, run the following:

Linux/OSX

CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -a -tags netgo -installsuffix netgo -ldflags '-w -s' .

Windows

$env:CGO_ENABLED=0; $env:GOOS="linux"; $env:GOARCH="amd64";
go build -a -tags netgo -installsuffix netgo -ldflags "-s"

Don't forget to unset the variables when you're done!

Remove-Item env:CGO_ENABLED; Remove-Item env:GOOS; Remove-Item env:GOARCH;

Using only Docker (no Go compiler)

Assuming docker is installed, run the folowing in the checked-out directory:

docker run --rm -v $PWD:/go/src/github.com/tydavis/showreadiness \
-w /go/src/github.com/tydavis/showreadiness golang:alpine /bin/sh \
-c "CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -a -tags netgo -installsuffix netgo -ldflags '-w -s' . "