Introduction

Cloudflare Load Balancer marking pool unhealthy when health check endpoint fails. This guide provides step-by-step diagnosis and resolution.

Symptoms

Typical error output:

bash
Error: Cloudflare operation failed
Check Cloudflare dashboard for details
wrangler tail for Workers logs

Common Causes

  1. 1.Configuration mismatch in Cloudflare dashboard
  2. 2.Resource limit exceeded for plan tier
  3. 3.Network or DNS propagation delay
  4. 4.Rule or policy too restrictive or misconfigured

Step-by-Step Fix

Step 1: Check Current State

bash
# Check Cloudflare status
wrangler tail  # For Workers
curl -I https://example.com  # For site issues
# Check dashboard: dash.cloudflare.com

Step 2: Identify Root Cause

bash
wrangler whoami
wrangler tail
curl -I https://your-domain.com

Step 3: Apply Primary Fix

```bash # Primary fix: Update configuration wrangler config wrangler deploy

# Check logs wrangler tail --format pretty ```

Step 4: Apply Alternative Fix

bash
# Alternative: Check via API
curl -X GET "https://api.cloudflare.com/client/v4/zones/<zone-id>/settings" \
  -H "Authorization: Bearer <api-token>"

Step 5: Verify the Fix

bash
curl -I https://example.com
wrangler tail
# Should show successful response

Common Pitfalls

  • Not waiting for DNS propagation
  • Using wrong zone ID in API calls
  • Forgetting to deploy after config changes
  • Not testing Workers locally before deploying

Best Practices

  • Use wrangler for local development and testing
  • Monitor Workers logs with wrangler tail
  • Set up alerts for WAF and DDoS events
  • Review analytics regularly for anomalies
  • Cloudflare 5xx Errors
  • Cloudflare DNS Resolution Failed
  • Cloudflare SSL Handshake Error
  • Cloudflare Cache Miss