Load Balancing

Distribute traffic across multiple backend servers with intelligent load balancing strategies.

Strategies

Round-Robin (Default)

Distributes requests evenly across all healthy backends.

{
  "loadBalancing": {
    "strategy": "round-robin"
  },
  "backends": [
    { "url": "http://backend1:3000" },
    { "url": "http://backend2:3000" },
    { "url": "http://backend3:3000" }
  ]
}

Weighted

Distributes requests based on weight. Perfect for canary deployments and A/B testing.

{
  "loadBalancing": {
    "strategy": "weighted"
  },
  "backends": [
    { "url": "http://stable:3000", "weight": 90 },
    { "url": "http://canary:3000", "weight": 10 }
  ]
}

IP-Hash

Routes requests from the same IP to the same backend. Provides session affinity.

{
  "loadBalancing": {
    "strategy": "ip-hash"
  },
  "backends": [
    { "url": "http://backend1:3000" },
    { "url": "http://backend2:3000" }
  ]
}

Least-Connections

Routes to the backend with the fewest active connections. Best for variable request durations.

{
  "loadBalancing": {
    "strategy": "least-connections"
  },
  "backends": [
    { "url": "http://backend1:3000" },
    { "url": "http://backend2:3000" }
  ]
}

Health Checks

Monitor backend health automatically:

{
  "backends": [
    {
      "url": "http://backend1:3000",
      "healthCheck": {
        "enabled": true,
        "path": "/health",
        "interval": 30000,
        "timeout": 5000,
        "unhealthyThreshold": 3,
        "healthyThreshold": 2
      }
    }
  ]
}

Health Check Options

Option	Description	Default
path	Health check endpoint	/health
interval	Check interval (ms)	30000
timeout	Request timeout (ms)	5000
unhealthyThreshold	Failures before marking unhealthy	3
healthyThreshold	Successes before marking healthy	2

Failover

When a backend becomes unhealthy:

1. It's removed from the rotation
2. Traffic is redistributed to healthy backends
3. Health checks continue in the background
4. Backend is restored when healthy again

Use Cases

Blue-Green Deployment

// Switch traffic from blue to green
{
  "loadBalancing": { "strategy": "weighted" },
  "backends": [
    { "url": "http://blue:3000", "weight": 0 },
    { "url": "http://green:3000", "weight": 100 }
  ]
}

Canary Release

// Gradually increase canary traffic
{
  "loadBalancing": { "strategy": "weighted" },
  "backends": [
    { "url": "http://stable:3000", "weight": 95 },
    { "url": "http://canary:3000", "weight": 5 }
  ]
}

Geographic Distribution

// Route based on backend location
{
  "loadBalancing": { "strategy": "round-robin" },
  "backends": [
    { "url": "http://us-east:3000" },
    { "url": "http://us-west:3000" },
    { "url": "http://eu-west:3000" }
  ]
}