High Availability and Scalability

You are running an application in three az, with an auto scaling group and a classic load balancer. It seems that the traffic si not evenly distributed amongst all the backend C2 instances, with some az being overloaded. Which feature should help distribute the traffic across all EC2 instances?

Cross Zone load balancing

You quickly created an ELB and it turns out your users are complaining about the fact that sometimes, the servers just don't work. You realize that indeed, your servers do crash ferom time to time. How to protect your users from seeing these crashes?

Enable health checks

The application load balancer can route to different target groups based on all these except...

Geography. Can route based on Hostname, request path, and source IP

Running an application on an auto scaling group that scales the number of instances in and out is called

Horizontal scalability

Your application is using an application load balancer. It turns out your application only sees traffic coming from private IP which are in fact your load balancer's. What should you doto find the true ip of the clients connected to your website?

Look into the X-Forwarded-For header in the backend

You are designing a high performance application that will require millions of connections to be handled as well as low latency. Best LB for this is...

Network Load Balancer

The Application load balancers target groups can be all of these except

Network load balancers Can target EC2 instances, IP addresses, and lambda functions

You would like to expose a fixed static IP to your end users for compliance purposes. So they can write firewall rules that will be stable and approved bty regulators. Which LB should you use

Network load balancers. Application and classic use static DNS (URL)

You are running at desired capacity of 3 and the maximum capacity of 3. You have alarms set at 60% CPU to scale out your app. Your app is now running at 80% capacity. What will happen?

Nothing

A web application hosted in EC2 is managed by an ASG. you are exposing this application through an application load balancer. The ALB is deployed on the VPC with the following CIDR: 192.168.0.0/18. How do you configure the EC2 instance security group to ensure only the ALB can access the port 80

Open up the EC2 security on port 80 to the ALB's security group

Your application load balancer currently is routing to two target groups. Ech of them is routed to based on hostname rules. You have been tasked with enabling HTTPS traffic for each hostname and have loaded the certificates onto the ALB. which ALB feature will help it choose the right certificate for your clients?

Server name indication (SNI)

Load balancers provide a

Static DNS name we can use in our application

Application Load Balancers handle all these protocols except

TCP

An application is deployed with an Application load balancer and an auto scaling group. Currently the scaling of the auto scaling group is done manually and you would like to define a scaling policy that will ensure the average number of connections to your EC2 instances is averaging around 1000. Which scaling policy should you use?

Target Tracking

I have an ASG and an ALB and I setup my ASG to get health status of instances thanks to my ALB. One instance has just been reported unhealthy. What will happen?

The ASG will terminate the EC2 instance

An ASG spawns across two availability zones. AZ-A has three EC2 instances and AZ-B has four EC2 instances. The ASG is about to go into a scale-in event. What will happen?

The AZ-B will terminate an instance with the oldest launch config

You are running a website with a load balancer and ten ec2 instances. Your users are complaining about the fact that your website always asks them to reauthenticate when they switch pages. You are puzzled, because it's working just fine on your machine and in the dev environment with 1 server. What could be the reason?

The Load Balancer does not have stickiness enabled

Your application load balancer is hosting three target groups with hostnames being users.example.com, api.external.example.com, and checkout.example.com. You would like to expose HTTPS traffic for each of these hostnames. How do you configure your ALB ssl certificates to make this work?

Use SNI SNI allows you to expose multiple SSL certs if the client supports it

Scaling an instance from an r4.large to r4.4xlarge is called

Vertical scalability

Your boss wants to scale your ASG based on the number of requests per minute your application makes to your database.

You create a CloudWatch custom metric and build an alarm on this to scale your ASG