Skip to main content
GET
/
health
Health Endpoint
curl --request GET \
  --url https://api.example.com/health
{
  "status": "<string>",
  "healthy_backends": "<string>",
  "uptime_seconds": 123
}

​
Overview

The /health endpoint provides real-time information about the load balancer’s operational status and backend server health.

​
Endpoint

GET /health

​
Response

​
status
string
Overall health status
  • ok: Load balancer is operating normally
  • degraded: Some backends are down but service continues
  • down: No healthy backends available
​
healthy_backends
string
Ratio of healthy backends (e.g., “3/3” or “2/3”)
​
uptime_seconds
number
Load balancer uptime in seconds since start

​
Example Request

curl http://localhost:8080/health

​
Example Response

​
All Backends Healthy

200 OK
{
  "status": "ok",
  "healthy_backends": "3/3",
  "uptime_seconds": 3600
}

​
Degraded State

200 OK
{
  "status": "degraded",
  "healthy_backends": "2/3",
  "uptime_seconds": 7200
}

​
No Healthy Backends

503 Service Unavailable
{
  "status": "down",
  "healthy_backends": "0/3",
  "uptime_seconds": 1800
}

​
Use Cases

livenessProbe:
  httpGet:
    path: /health
    port: 8080
  initialDelaySeconds: 10
  periodSeconds: 5

HEALTHCHECK --interval=5s --timeout=3s --retries=3 \
  CMD curl -f http://localhost:8080/health || exit 1

#!/bin/bash
response=$(curl -s http://localhost:8080/health)
status=$(echo $response | jq -r '.status')

if [ "$status" != "ok" ]; then
  echo "ALERT: Load balancer unhealthy"
  # Send alert
fi
If you have multiple UltraBalancer instances behind a load balancer:
upstream ultrabalancer_cluster {
  server ultra1:8080;
  server ultra2:8080;
}

# Health check
health_check interval=5s fails=3 passes=2 uri=/health;

​
Status Interpretation

​
ok
All configured backends are healthy. The load balancer is fully operational.
​
degraded
One or more backends are unhealthy, but at least one backend is available. Service continues with reduced capacity.
​
down
No backends are available. The load balancer cannot serve requests.

​
Uptime Calculation

The uptime_seconds field represents how long the load balancer has been running since its last start. This counter resets to 0 when:
  • The process is restarted
  • Configuration is reloaded (in future versions)
  • The system reboots
Use this field to track restart frequency and overall stability.

​
Integration Examples

​
Prometheus Blackbox Exporter

Monitor health endpoint availability:
prometheus.yml
scrape_configs:
  - job_name: 'ultrabalancer-health'
    metrics_path: /probe
    params:
      module: [http_2xx]
    static_configs:
      - targets:
        - http://ultrabalancer:8080/health
    relabel_configs:
      - source_labels: [__address__]
        target_label: __param_target
      - source_labels: [__param_target]
        target_label: instance
      - target_label: __address__
        replacement: blackbox-exporter:9115

​
Grafana Alert

Create alert when health degrades: 
alert: UltraBalancerDegraded
expr: ultrabalancer_healthy_backends_ratio < 1
for: 5m
labels:
  severity: warning
annotations:
  summary: "UltraBalancer has unhealthy backends"
  description: "Only {{ $value }} backends are healthy"

​
Next Steps

Metrics Endpoint

Get detailed performance metrics

Health Checks

Configure health checking

Monitoring Guide

Set up comprehensive monitoring

Prometheus

Prometheus metrics format