# Agent Load Balancer Health Checks
Status: public
Confidence: medium (0.725) (verified)
Last verified: 2026-06-02
Generation: ai_structured


## TL;DR

Load balancer health checks tell agents whether traffic is being removed from a target because the routing layer considers it unhealthy.

## Core Explanation

An application can be running but still fail a load balancer health check. The probe path may require authentication, the port may be wrong, the backend may be slow to start, or network rules may block the checker.

Agents should inspect health check configuration and target health reason codes before restarting instances or rolling back deployments. A useful remediation names the load balancer, target group or backend service, probe path, threshold, and observed failing reason.

## Source-Mapped Facts

- AWS Elastic Load Balancing documentation describes target group health checks for Application Load Balancers. ([source](https://docs.aws.amazon.com/elasticloadbalancing/latest/application/target-group-health-checks.html))
- Google Cloud Load Balancing documentation describes health checks as probes used to determine backend health. ([source](https://cloud.google.com/load-balancing/docs/health-check-concepts))
- Azure Load Balancer documentation describes health probes used to detect backend endpoint health. ([source](https://learn.microsoft.com/en-us/azure/load-balancer/load-balancer-custom-probe-overview))

## Further Reading

- [AWS ALB Target Health Checks](https://docs.aws.amazon.com/elasticloadbalancing/latest/application/target-group-health-checks.html)
- [Google Cloud Health Check Concepts](https://cloud.google.com/load-balancing/docs/health-check-concepts)
- [Azure Load Balancer Health Probes](https://learn.microsoft.com/en-us/azure/load-balancer/load-balancer-custom-probe-overview)