3.5.2 - Elastic Load Balancing (ELB)
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Introduction to Elastic Load Balancing
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Today, weβre diving into Elastic Load Balancing, or ELB for short. Can anyone tell me why load balancing is important in cloud applications?
Is it to distribute traffic evenly across servers?
Exactly, Student_1! By distributing traffic, ELB ensures that one server is not overwhelmed while others are underutilized.
What happens if one of the servers goes down?
Great question, Student_2! ELB will automatically reroute traffic away from unhealthy servers, maintaining application availability.
Remember, 'ELB = Traffic + Availability + Resilience'.
Types of Elastic Load Balancers
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Now letβs talk about the different types of ELB. What do you think the Application Load Balancer does?
Does it handle web traffic since it operates at Layer 7?
Correct! The Application Load Balancer is perfect for web applications that need advanced routing features.
What about Network Load Balancer?
The Network Load Balancer operates at Layer 4, ideal for applications that require low latency, such as gaming or financial applications. Keep this in mind: 'Layer 7 = App, Layer 4 = Speed'.
Integration of Auto Scaling with ELB
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How does ELB collaborate with Auto Scaling? Any thoughts?
Doesnβt Auto Scaling adjust the number of running instances based on traffic?
Yes, thatβs correct! It scales the number of instances while ELB manages the distribution of traffic to those instances.
So if traffic increases, Auto Scaling adds more instances, and ELB routes traffic to them?
Perfect, Student_2! This synergy ensures optimal performance even under varying loads. Remember the phrase: 'Scale when needed, balance as you grow'.
Introduction & Overview
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Quick Overview
Standard
This section explains how Elastic Load Balancing (ELB) works in conjunction with Auto Scaling to ensure high availability and scalability for applications. Different types of ELB, including Application Load Balancer, Network Load Balancer, and Classic Load Balancer, are discussed along with their use cases.
Detailed
Elastic Load Balancing (ELB)
Elastic Load Balancing (ELB) is a key feature of AWS that intelligently distributes incoming application traffic across multiple Amazon EC2 instances. By distributing the traffic, ELB increases your application's fault tolerance, ensuring that users continue to receive consistent performance even when some instances are under heavy load or fail. ELB works closely with Auto Scaling, which automatically adjusts the number of EC2 instances based on demand.
Key Types of Elastic Load Balancers
- Application Load Balancer (ALB): Works at the HTTP/HTTPS layer (Layer 7), supports advanced routing based on content type. Ideal for microservices.
- Network Load Balancer (NLB): Operates at the TCP layer (Layer 4) for ultra-low latency. Suitable for applications requiring extreme performance and static IP addresses.
- Classic Load Balancer: A legacy option supporting both Layer 4 and Layer 7, used for applications built within the EC2 classic network.
How ELB Works with Auto Scaling
Together, ELB and Auto Scaling ensure that your application remains highly available and can dynamically scale up or down based on user demands and the health of instances. ELB routes traffic only to healthy instances, while Auto Scaling adjusts the number of instances according to the preset policies, maintaining optimal performance and cost efficiency.
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Overview of Elastic Load Balancing (ELB)
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Chapter Content
Elastic Load Balancing (ELB) Distributes incoming network traffic across multiple instances. Increases fault tolerance by rerouting traffic away from unhealthy instances.
Detailed Explanation
Elastic Load Balancing (ELB) is a service that helps manage incoming network traffic to ensure that no single instance becomes overwhelmed with requests. By distributing the traffic across multiple instances, ELB enhances the reliability of your application. If one instance becomes unhealthy or fails, ELB will automatically redirect the traffic to healthy instances, thus maintaining the availability of your service.
Examples & Analogies
Think of ELB like a traffic director at a busy intersection. Just as the director ensures that cars are evenly distributed between lanes to avoid bottlenecks, ELB ensures that user requests are evenly distributed among multiple servers to maintain smooth operation.
Types of Elastic Load Balancers
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Chapter Content
Supports different types: Application Load Balancer: Works at HTTP/HTTPS layer (Layer 7), supports advanced routing. Network Load Balancer: Works at TCP layer (Layer 4), supports ultra-low latency. Classic Load Balancer: Legacy option supporting both Layer 4 and 7.
Detailed Explanation
ELB offers various types of load balancers suited for different use cases. The Application Load Balancer operates at the application layer (Layer 7), allowing for more complex routing decisions based on HTTP requests, which is useful for applications that need advanced features like host-based routing. The Network Load Balancer functions at the transport layer (Layer 4) and is designed for extreme performance and low latency, making it ideal for real-time traffic. Finally, the Classic Load Balancer is an older option that supports both layers but lacks some of the features of the newer types.
Examples & Analogies
Imagine a restaurant with different dining areas. An Application Load Balancer is like a host who directs customers to specific tables based on their preferences (such as a quiet area or a place with a view). A Network Load Balancer is akin to a waiter who swiftly serves customers without any unnecessary delay. The Classic Load Balancer is similar to a general seating arrangement where anyone can sit anywhere without much thought.
How ELB and Auto Scaling Work Together
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Chapter Content
ELB sends incoming traffic to healthy instances. Auto Scaling changes the number of instances dynamically. Together, they ensure your application is highly available, scalable, and fault-tolerant.
Detailed Explanation
ELB and Auto Scaling work in tandem to provide a robust infrastructure for your applications. While ELB manages the distribution of traffic to ensure that user requests are handled by healthy instances, Auto Scaling adjusts the number of instances based on the traffic. During high demand, Auto Scaling can launch new instances to handle the additional load, and when demand decreases, it can terminate unnecessary instances to save costs, maintaining efficiency.
Examples & Analogies
Consider a concert venue. ELB is like the ushers who direct attendees to open seats, while Auto Scaling is like the management team that decides to add more rows of chairs when a large crowd shows up and remove extra chairs when the crowd thins out. Together, they ensure that everyone has a seat without wasting resources.
Key Concepts
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Elastic Load Balancing (ELB): A service that balances traffic across multiple EC2 instances for fault tolerance.
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Application Load Balancer: A type of ELB focused on HTTP traffic with advanced routing capabilities.
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Network Load Balancer: A type of ELB designed for rapid TCP traffic with ultra-low latency.
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Auto Scaling: A feature that automatically adjusts the number of EC2 instances based on real-time demand.
Examples & Applications
Using ELB to route traffic for an e-commerce website ensures that during high sales events, the traffic is distributed to multiple healthy instances.
In a financial application, a Network Load Balancer provides fast transaction processing by directing requests to the least busy instances.
Memory Aids
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Rhymes
If traffic is high, don't be shy, ELB will balance as the minutes fly.
Stories
Imagine a restaurant with multiple chefs; when many customers arrive, they call in more help to keep the kitchen running smoothly. ELB does the same for your servers.
Memory Tools
A + N = Better - Remember Application and Network Load Balancers for different traffic needs.
Acronyms
ELB
Everyone Loves Balance - Think of it as providing balance to traffic management.
Flash Cards
Glossary
- Elastic Load Balancing (ELB)
A service that distributes incoming application traffic across multiple targets, such as EC2 instances.
- Application Load Balancer (ALB)
A load balancer that operates at the HTTP layer to provide advanced routing features.
- Network Load Balancer (NLB)
A load balancer that operates at the TCP layer, ideal for ultra-low latency connections.
- Auto Scaling
An AWS service that automatically adjusts the number of EC2 instances based on demand.
- Fault Tolerance
The ability of a system to continue operating without interruption when one or more components fail.
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