Azure Load Balancer is a Layer 4 (TCP/UDP) load balancer that enables you to distribute network traffic. It can balance incoming traffic across multiple virtual machines or containers. Azure Load Balancer operates at the transport layer and uses a hash-based distribution algorithm. There are two types of Azure Load Balancers:
Standard Load Balancer
The Standard Load Balancer offers advanced features and capabilities for high availability and scalability. It's designed for production workloads requiring robust performance and reliability.
Key Features:
- High availability and fault tolerance.
- Supports both inbound and outbound load balancing.
- Advanced health probes to monitor backend instance health.
- Network Security Group (NSG) integration for enhanced security.
- Support for Availability Zones for maximum resilience.
- Supports TCP, UDP, and HTTPS (SSL/TLS termination can be handled by Application Gateway or other services).
- Customizable load balancing rules and session persistence.
- Gateway Load Balancer integration for network virtual appliances.
Use Cases:
- Mission-critical applications requiring high availability.
- Web applications with fluctuating traffic.
- Applications that need to scale horizontally.
- Scenarios requiring granular control over traffic distribution.
Basic Load Balancer
The Basic Load Balancer is a simpler, more cost-effective solution suitable for development, testing, and non-critical workloads. It provides basic load balancing capabilities.
Key Features:
- Basic inbound load balancing.
- Supports TCP and UDP protocols.
- Standard health probes.
- Does not support Availability Zones.
- Limited SKU features compared to Standard.
- Generally recommended for non-production environments or simple workloads.
Use Cases:
- Development and testing environments.
- Simple, non-critical applications.
- Scenarios where cost is a primary concern and advanced features are not required.
Load Balancer Type Comparison
| Feature | Basic Load Balancer | Standard Load Balancer |
|---|---|---|
| HA & Fault Tolerance | Basic | High |
| Availability Zones Support | No | Yes |
| NSG Integration | No | Yes |
| Outbound Load Balancing | No (only inbound) | Yes |
| Gateway Load Balancer Integration | No | Yes |
| SKU Features | Limited | Advanced |
| Recommended For | Dev/Test, Non-production | Production, Mission-critical |
| Cost | Lower | Higher |