Resolving Kong Ingress Ring Balancer Errors: Failure to Get Peer

The error message “failure to get a peer from the ring balancer” in Kong Ingress indicates that the load balancer couldn’t connect to any of the upstream targets. This issue is significant because it can lead to service disruptions, causing requests to fail and potentially returning HTTP 503 errors. Understanding and resolving this error is crucial for maintaining the reliability and availability of services managed by Kong Ingress.

Causes of the Error

The error message “failure to get a peer from the ring balancer using Kong Ingress” can be caused by several factors:

1. No Targets Configured: The upstream entity has no targets. This can be checked using the Admin API /upstreams endpoint.

2. Unhealthy Targets: Targets exist but are not healthy. This can result from network or DNS issues, backend problems, etc. Use the Admin API /health endpoint to review target health.

3. Unhealthy Balancer: The balancer itself is unhealthy. This can be confirmed by including the balancer_health=1 query parameter in the /health endpoint.

4. Version-Specific Bugs: Certain versions of Kong may have bugs causing this issue. Upgrading to a newer version might resolve the problem.

5. Configuration Issues: Misconfigurations in the Kong Ingress Controller or the upstream services can lead to this error. Ensure all configurations are correct and consistent.

6. Network Problems: Issues with network connectivity between Kong and the upstream services can also cause this error.

These are common scenarios and configurations that might lead to the “failure to get a peer from the ring balancer” error in Kong Ingress.

Diagnosing the Error

Sure, here are the steps and tools for diagnosing the “failure to get a peer from the ring balancer” error in Kong Ingress:

1. Check Upstream Targets:

   • Command: curl -H "kong-admin-token: kong" http://localhost:8001/upstreams/<upstream_name>/targets/all
   • Log: Admin API /upstreams endpoint.

2. Verify Target Health:

   • Command: curl http://localhost:8001/upstreams/<upstream_name>/health -s | jq .
   • Log: Admin API /health endpoint.

3. Check Balancer Health:

   • Command: curl http://localhost:8001/upstreams/<upstream_name>/health?balancer_health=1 -s | jq .
   • Log: Admin API /health endpoint with balancer_health=1 query parameter.

4. Review Kong Logs:

   • Location: /usr/local/kong/logs/error.log
   • Command: tail -f /usr/local/kong/logs/error.log

5. Inspect Kong Configuration:

   • Command: kong config db_export
   • Log: Configuration file.

6. Check Network/DNS Issues:

   • Command: nslookup <upstream_target>
   • Log: Network diagnostic tools.

7. Update Kong Version:

   • Command: kong version
   • Log: Ensure you are using the latest stable version of Kong.

These steps should help you diagnose and resolve the issue effectively.

Resolving the Error

To resolve the “failure to get a peer from the ring balancer” error in Kong Ingress, follow these steps:

1. Check Upstream Targets:

   • Ensure upstream entities have targets configured.
   • Use the Admin API: curl -H "kong-admin-token: kong" http://localhost:8001/upstreams/kong_upstream/targets/all.

2. Verify Target Health:

   • Confirm targets are healthy and not failing health checks.
   • Use the Admin API: curl http://localhost:8001/upstreams/kong_upstream/health.

3. Balancer Health:

   • Check the health of the balancer itself.
   • Use the Admin API with balancer_health=1: curl http://localhost:8001/upstreams/kong_upstream/health?balancer_health=1.

4. Update Kong Version:

   • Upgrade to the latest stable version of Kong, as some issues may be resolved in newer releases.

5. Configuration Changes:

   • Ensure proper DNS resolution for upstream targets.
   • Adjust health check settings to match your environment’s needs.

6. Best Practices:

   • Regularly monitor and maintain the health of upstream services.
   • Implement active health checks to proactively detect issues.
   • Secure the Admin API with authentication and limit exposure.

These steps should help you address and resolve the error effectively.

Preventing Future Occurrences

To prevent the “failure to get a peer from the ring balancer” error in Kong Ingress, consider the following strategies:

Monitoring

1. Health Checks: Regularly monitor the health of upstream targets using Kong’s Admin API. Ensure that all targets are healthy and responsive.
2. Network Monitoring: Implement network monitoring tools to detect and resolve connectivity issues promptly.
3. Log Analysis: Continuously analyze logs for any signs of upstream or network issues. Use tools like ELK stack for centralized logging and alerting.

Maintenance

1. Regular Updates: Keep Kong and its dependencies up to date to benefit from the latest fixes and improvements.
2. Configuration Reviews: Periodically review and validate the configuration of upstreams and targets to ensure they are correct and optimized.
3. Resource Scaling: Ensure that upstream services have sufficient resources to handle the load. Scale resources as needed to prevent bottlenecks.

Proactive Measures

1. Redundancy: Configure multiple upstream targets to provide redundancy. This ensures that if one target fails, others can handle the traffic.
2. Firewall Rules: Verify and update firewall rules to allow necessary traffic between nodes and the ring balancer.
3. DNS Configuration: Ensure DNS settings are correctly configured and that DNS servers are reliable to avoid resolution issues.

Implementing these strategies will help maintain a robust and reliable Kong Ingress setup, minimizing the chances of encountering the “failure to get a peer from the ring balancer” error.

The Error ‘Failure to Get a Peer from the Ring Balancer’ in Kong Ingress

The error message ‘failure to get a peer from the ring balancer’ in Kong Ingress indicates that the load balancer couldn’t connect to any upstream targets, leading to service disruptions and potential HTTP 503 errors.

This issue can be caused by various factors including:

• No targets configured
• Unhealthy targets
• Unhealthy balancer
• Version-specific bugs
• Configuration issues
• Network problems
• Misconfigured DNS settings

Resolving the Error

To resolve this error, check:

• Upstream targets
• Target health
• Balancer health

Additionally, review Kong logs, inspect Kong configuration, and update Kong version. Regular monitoring, maintenance, and proactive measures such as:

• Redundancy
• Firewall rules
• DNS configuration

can help prevent this error.