<p>In the Kubernetes/Docker ecosystem there is a convention of using <code>/healthz</code> as a health-check endpoint for applications.</p>

<p>Where does the name 'healthz' come from, and are there any particular semantics associated with that name?</p>

<p>It historically comes from Google’s internal practices. They're called "z-pages".</p>

<p>The reason it ends with <code>z</code> is to reduce collisions with actual application endpoints with the same name (like <code>/status</code>). See this talk for more: <a href="https://vimeo.com/173610242" rel="noreferrer">https://vimeo.com/173610242</a></p>

<p>Similar endpoints (at least inside Google) are <code>/varz</code>, <code>/statusz</code>, <code>/rpcz</code>. Services developed at Google automatically get these endpoints to export their health and metrics and there are tools that collect the exposed metrics/statuses from all the deployed services.</p>

<p>Open source tools like Prometheus implement this pattern (since original authors of Prometheus are also ex-Googlers) by coming to a well-known endpoint to collect metrics from your application. Similarly <a href="http://opencensus.io" rel="noreferrer">OpenCensus</a> allows you to expose z-pages from your app (ideally on a different port) to diagnose problems.</p>
