What is AWS application load balancer?
An AWS load balancer distributes incoming traffic across multiple targets, such as EC2 instances, containers, and IP addresses, within one or more availability zones. Load balancers are crucial in cloud computing, especially for applications requiring many users or high availability. Load balancers direct incoming traffic based on the request attributes to instances called targets.
The instances that serve as targets form a logical grouping called a target group.
AWS boad balancer uses listeners to assess the incoming requests and forward them to targets. Listeners use rules to evaluate incoming requests.
An Application load balancer (ALB) works at the application layer of the OSI model . ALBs are designed to route traffic based on the content of the request, making them ideal for applications that rely on HTTP/HTTPS protocols. After ALB receives a request, it examines the content of the request, including details like the URL, host, and headers.
Based on this information, it makes intelligent routing decisions. ALB simplifies and improves the application’s security, ensuring the latest TLS/SSL ciphers and protocols are always used.
Why do we need application load balancer?
Consider a real world scenario: An e-commerce website experiences significant traffic during a major sales event. Traffic is surging, and your website’s performance is crucial. Without an ALB, a single server would bear the burden, risking overloading and potential crash. However, an ALB intelligently distributes incoming requests across multiple servers, ensuring each handles a manageable load. It not only prevents server overload but also maintains a seamless user experience.
If one server fails, the ALB swiftly redirects traffic to healthy ones, ensuring uninterrupted service.
Advantages of application load balancer
High availability and fault tolerance: ALBs ensure traffic is automatically redirected to healthy instances, minimizing downtime even if one server or instance fails.
Advanced routing capabilities: ALBs operate at the application layer (layer 7) and can make routing decisions based on content such as URL, host, and headers. It allows for more granular control over traffic distribution.
Health checks and automatic failover: ALBs continuously monitor the health of registered targets. If a target becomes unhealthy, the ALB automatically routes traffic away, ensuring high availability.
Integration with AWS services: ALBs can seamlessly integrate with other AWS services like Amazon ECS, AWS Fargate, and AWS Lambda, making them a crucial component for various applications.
Auto scaling integration: ALBs work with AWS auto scaling to adjust the number of running instances based on traffic load. It helps in handling sudden spikes in traffic and vice versa.
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What is the primary function of an AWS load balancer?
Distributing incoming traffic across multiple destinations
Monitoring network latency
Shuts down the entire system
Sends an alert to the administrator
In summary, an AWS load balancer distributes incoming traffic across multiple targets, such as EC2 instances, containers, and IP addresses, within one or more availability zones, making it essential for applications with many users or requiring high availability.
It uses listeners and rules to evaluate and forward requests to appropriate targets within target groups.
The Application load balancer (ALB) operates at the application layer (layer 7) of the OSI model. It routes traffic based on request content, such as URLs and headers, to improve security and performance. ALBs provide high availability, fault tolerance, advanced routing features, and health checks.
They also integrate easily with AWS services. Because of these features, ALBs are essential for managing traffic during high-demand events, such as sales on an e-commerce site.
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