Manage Azure Load Balancers
Key Concepts
- Azure Load Balancer
- Load Balancing Rules
- Health Probes
- Outbound Rules
Azure Load Balancer
Azure Load Balancer distributes incoming traffic across multiple virtual machines (VMs) or services to ensure high availability and reliability. It operates at Layer 4 (Transport Layer) of the OSI model and supports both internal and public load balancing.
Example: Think of a load balancer as a traffic cop directing cars to different lanes to ensure smooth traffic flow. This prevents any single lane from becoming congested and ensures all lanes are utilized efficiently.
Load Balancing Rules
Load Balancing Rules define how incoming traffic is distributed across backend pool instances. These rules map a frontend IP configuration and port to multiple backend IP addresses and ports. Common load balancing methods include Round Robin, Least Connections, and Source IP affinity.
Analogy: Consider load balancing rules as the rules of a game where each player (backend instance) gets a turn (traffic) based on predefined criteria. For example, in Round Robin, each player gets an equal turn in sequence.
Health Probes
Health Probes monitor the health of backend instances to ensure traffic is only sent to healthy instances. Probes can check the status of a specific port and respond based on predefined criteria, such as HTTP status codes or TCP acknowledgments. If an instance fails a health probe, it is removed from the load balancer's rotation.
Example: Think of health probes as a doctor checking the health of patients. Only healthy patients (instances) are allowed to participate in activities (handle traffic), while unhealthy ones are sent to rest (removed from the rotation).
Outbound Rules
Outbound Rules configure how outbound connections from backend instances are handled. These rules allow you to define how traffic from backend instances to the internet is managed, including SNAT (Source Network Address Translation) and connection limits.
Analogy: Consider outbound rules as customs regulations for a country. They define how people (backend instances) can travel to other countries (the internet) and what they can bring with them (traffic management).
Conclusion
Managing Azure Load Balancers involves understanding and effectively using key concepts such as load balancing rules, health probes, and outbound rules. By leveraging these features, you can ensure your applications are highly available, reliable, and efficiently handle varying traffic loads.