What is a Load Balancer?
A load balancer is a device or software that distributes network or application traffic across multiple servers. This ensures no single server bears too much demand, improving responsiveness and availability.
How Load Balancers Work
When a user makes a request to a website or application, the load balancer intercepts the request and routes it to one of the available servers based on various algorithms and health checks.
Key Functions
- Traffic Distribution: Evenly distributes incoming requests across multiple servers
- Health Monitoring: Continuously checks server health and removes failed servers from the pool
- Scalability: Allows adding or removing servers without disrupting service
- Security: Can provide DDoS protection, SSL termination, and other security features
Types of Load Balancing Algorithms
1. Round Robin
Requests are distributed sequentially across servers in a list.
2. Least Connections
New requests are sent to the server with the fewest active connections.
3. IP Hash
The client’s IP address determines which server receives the request.
4. Weighted
Servers with more capacity receive more requests based on assigned weights.
Benefits
- High Availability: Ensures applications remain accessible even if servers fail
- Scalability: Easily handles increased traffic by adding more servers
- Performance: Reduces response time by distributing load efficiently
- Reliability: Provides redundancy and fault tolerance