Load Balancers and High Availability

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What is the goal of high availability?

To vertically scale an application

To increase the number of systems for an application

To survive a data center loss (correct)

To provide unlimited scalability

Which type of scalability is common for modern web applications?

Static scalability

Horizontal scalability (correct)

Vertical scalability

Diagonal scalability

What is the key difference between vertical and horizontal scaling?

Vertical scaling involves adding more instances, while horizontal scaling increases instance size

Vertical scaling increases instance size, while horizontal scaling adds more instances/systems (correct)

Vertical scaling is used in cloud environments, while horizontal scaling is used in on-premise setups

Vertical scaling implies distributed systems, while horizontal scaling is limited to single-server setups

In the context of EC2, what is the role of Load Balancers?

Elastic Load Balancers are servers that forward traffic to multiple servers downstream Signup and view all the answers

Which term refers to increasing the number of instances of an application?

Horizontal Scalability Signup and view all the answers

What does running instances for the same application across multi AZ contribute to?

High Availability Signup and view all the answers

In the context of high availability, what does passive high availability refer to?

Having redundant systems in place but only one actively handling traffic Signup and view all the answers

Elastic Load Balancer helps in ensuring what aspect of an application?

Load Distribution and High Availability Signup and view all the answers

What does Auto Scaling Group facilitate in terms of scalability?

Automatically adjusting instance sizes based on demand Signup and view all the answers

What feature of SSL certificates does the Application Load Balancer (v2) support?

Supports multiple listeners with multiple SSL certificates Signup and view all the answers

Which Load Balancer type uses Server Name Indication (SNI) to support multiple SSL certificates?

Application Load Balancer (v2) Signup and view all the answers

What is the purpose of Connection Draining in Elastic Load Balancers?

Ensure in-flight requests complete before de-registering instances Signup and view all the answers

Which Load Balancer type stops sending new requests to an EC2 instance that is de-registering?

Classic Load Balancer (v1) Signup and view all the answers

What does an Auto Scaling Group (ASG) aim to achieve?

Scale in or out based on load fluctuations Signup and view all the answers

What is the key function of Server Name Indication (SNI) in Load Balancers?

Allow serving multiple SSL certificates on a single IP address Signup and view all the answers

What is a key feature of Application Load Balancers in handling downstream instances?

Exposing only a single point of access (DNS) Signup and view all the answers

How does an Application Load Balancer ensure high availability?

By seamlessly handling failures of downstream instances Signup and view all the answers

In what way does SSL termination (HTTPS) play a role in Application Load Balancers?

It integrates with AWS Certificate Manager (ACM) Signup and view all the answers

Why is spreading the load across multiple downstream instances essential for a load balancer?

To handle increased traffic and prevent overload on individual instances Signup and view all the answers

Which factor makes using an Elastic Load Balancer more appealing compared to setting up your own load balancer?

Guaranteed high availability and managed maintenance by AWS Signup and view all the answers

How does enforcing stickiness with cookies contribute to the efficiency of an Application Load Balancer?

It ensures that requests from the same client go to the same instance Signup and view all the answers

What does the health check response '200 (OK)' indicate about an instance in the context of Load Balancers?

The instance is healthy Signup and view all the answers

Which layer of the OSI model does the Application Load Balancer (ALB) operate at?

Layer 7 (Application layer) Signup and view all the answers

What is a feature of Application Load Balancers (ALB) that makes them a great fit for microservices and container-based applications?

Capability to route based on Query String and Headers Signup and view all the answers

In an Application Load Balancer (ALB), what type of routing is based on the path in a URL such as 'example.com/users'?

Path-based routing Signup and view all the answers

What is a notable feature of Application Load Balancers (ALB) related to handling HTTP/2 and WebSockets?

Ability to handle HTTP/2 and WebSockets Signup and view all the answers

How can Application Load Balancers (ALB) route traffic based on different target groups?

Routing based on different target group configurations Signup and view all the answers

In an Application Load Balancer (ALB), what does the X-Forwarded-For header provide for the application servers?

The true IP of the client Signup and view all the answers