Load Balancing Patterns

Distribute traffic across infrastructure using the appropriate load balancing approach, from simple round-robin to global multi-region failover.

When to Use This Skill

Use load-balancing-patterns when:

• Distributing traffic across multiple application servers
• Implementing high availability and failover
• Routing traffic based on URLs, headers, or geographic location
• Managing session persistence across stateless backends
• Deploying applications to Kubernetes clusters
• Configuring global traffic management across regions
• Implementing zero-downtime deployments (blue-green, canary)
• Selecting between cloud-managed and self-managed load balancers

Core Load Balancing Concepts

Layer 4 vs Layer 7

Layer 4 (L4) - Transport Layer:

• Routes based on IP address and port (TCP/UDP packets)
• No application data inspection, lower latency, higher throughput
• Protocol agnostic, preserves client IP addresses
• Use for: Database connections, video streaming, gaming, financial transactions, non-HTTP protocols

Layer 7 (L7) - Application Layer:

• Routes based on HTTP URLs, headers, cookies, request body
• Full application data visibility, SSL/TLS termination, caching, WAF integration
• Content-based routing capabilities
• Use for: Web applications, REST APIs, microservices, GraphQL endpoints, complex routing logic

For detailed comparison including performance benchmarks and hybrid approaches, see references/l4-vs-l7-comparison.md.

Load Balancing Algorithms