Health Check Best Practices

health_check_best_practices.md

Health Check Best Practices

This is assumed to be in a webapp/SaaS context where there is plenty of http/https traffic already.

• Do as little work in your health check as possible. It is like a CPU interrupt in that way.

• Respond with an http status of 200 if all is well. Respond with 500 if there is a failure.

• Optionally also include JSON in your response.

    {
      "status": "green",
      "name": "foo",
      "totalPipelines": 20,
      "totalSessions": 10,
      "avgResponseMs": 10
    }
  

• If your web app stops acceptign connections when it gets busy then a side-channel is needed. Typically this would be done by creating a new http service on a new port that is able to determine the health of the web app of interest.

Additional reading

• Monitoring checklist - What things should I be monitoring? has good insights for which metrics to choose
• haproxy docs on health checks
• Is there a standard way to check if a web API is alive? hints that more stuff like this document is desperately needed.