Frequently Asked Questions
Why is my origin receiving so many health monitor requests?
This issue may be caused by a combination of two issues.
Multiple Health Monitor Regions
If you select multiple regions or choose All Data Centers (Enterprise Only), you may to that pool and its associated origins. Each region sends individual health monitor requests from 3 data centers. Using All Data Centers sends individual health monitor requests from all existing Cloudflare data centers (and that number of data centers is growing all the time).
To reduce traffic, reduce the number of selected regions or choose an option besides All Data Centers.
Low intervals for health monitor requests
If you have a low interval for your health monitor requests, you may increase the traffic sent to your origin server.
Why is my origin or pool considered unhealthy?
- Perform a
curlrequest against the configured endpoint. Make sure the response you are seeing matches your settings for the monitor.
- Ensure your firewall or web server does not block or rate limit and accepts requests from .
- If you are looking for a specific value in the Response Body, make sure that value is relatively static and within the first 10 KB of the HTML page.
- If your origin responds with a
302status code, make sure Follow Redirects is selected.
- Try increasing the Timeout value.
- Review the Host Header for the health monitor.
- If you are using , , make sure that you entered a zone value for Simulate Zone.
Why does my load balancer route traffic to a secondary pool when the primary pool is still healthy?
You occasionally might see traffic routed away from a pool if a health monitor request fails from a specific data center (even if the origin is still healthy). That data center may direct a small number of requests to another pool that is considered healthy by that data center.
What happens when a pool or origin becomes unhealthy?
What is the difference between Load Balancing and Health Checks?
helps monitor origin server health and — based on that and other information — route incoming requests accordingly. Individual origin servers have monitors attached, which issue monitor requests at regular intervals.
Why do I see different numbers of requests in Load Balancing Analytics?
Load balancing requests are the number of uncached requests made by your load balancer. By default, Cloudflare caches resolved IP addresses for up to five seconds. This built-in caching is often the cause of an discrepancies.