Cloudflare load balancer - endpoint health

To set up endpoint health monitoring for your Cloudflare load balancer, you need a way to determine the health of your load balancer VMs. Since these VMs don't host content themselves but only pass requests to upstream servers, you can implement a simple health check endpoint on each load balancer. Here's how you can do it:

1. Create a Health Check Endpoint: You can configure a simple HTTP endpoint on each load balancer that returns a 200 OK status if the load balancer is operational. This can be done by setting up a basic Nginx or Apache server with a static HTML page or a simple script.

2. Configure Nginx (or Apache): If you're using Nginx, you can create a new server block to serve a health check page. Here's an example configuration for Nginx:

   server {
       listen 80;
       server_name your-load-balancer-ip;
   
       location /health {
           return 200 'OK';
           add_header Content-Type text/plain;
       }
   }
   

   This configuration listens on port 80 and responds with a 200 OK status for requests to /health.

3. Set Up Cloudflare Health Checks: In the Cloudflare dashboard, configure a health check for each endpoint in your load balancer pool. Point the health check to the /health endpoint you created. Ensure that the health check is set to expect a 200 OK response.

4. Test the Configuration: After setting up the health check, test it by accessing the /health endpoint directly in a browser or using a tool like curl to ensure it returns the expected response.

   curl http://your-load-balancer-ip/health
   

   You should see OK as the response.

5. Monitor and Adjust: Monitor the health check results in the Cloudflare dashboard. If any issues arise, you can adjust the configuration or troubleshoot the load balancer as needed.

By implementing a simple health check endpoint, you enable Cloudflare to monitor the health of your load balancers and perform DNS failover when necessary. This approach ensures that your load balancers are always ready to route traffic to the upstream servers.