Where does the convention of using /healthz for application health checks come from?

Question

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

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

ahmet alp balkan · Accepted Answer · 2019-07-11T17:07:41.263

388

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

The reason it ends with z is to reduce collisions with actual application endpoints with the same name (like /status). See this talk for more: https://vimeo.com/173610242

Similar endpoints (at least inside Google) are /varz, /statusz, /rpcz. 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.

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 OpenCensus allows you to expose z-pages from your app (ideally on a different port) to diagnose problems.

edited Jul 11 '19 at 17:07

answered Apr 12 '17 at 23:12

ahmet alp balkan

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Go expvar https://golang.org/pkg/expvar/ is quite close to /varz – ptman May 22 '20 at 12:08
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@AhmeB: Thank you for the video link. it help me understand little more about healthz – Gatsby Lee Jun 29 '20 at 23:04
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Question is answered at 26:55 in the talk (but this answer already contains pretty much the entire answer given by Kelsey). – tjanson Sep 11 '20 at 19:06

Where does the convention of using /healthz for application health checks come from?

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