EC2 - Solutions Architect Associate Level

Question 1

Describe an Elastic IP (EIP)

Answer 1

An EIP is a public IPv4 IP you own and doesn’t change, as long as you own it.

Question 2

Describe cluster placement groups, their pros/cons, and when they should be used

Answer 2

Clusters instances into a low-latency group within a single Availability Zone. This is high performance, but high risk.

Pros: Great network
Cons: If rack fails, all instances fail at the same time

Use for big data job that needs to complete fast, or app that needs extremely low latency and high network throughput.

Question 3

Describe spread placement groups, their pros/cons, and when they should be used

Answer 3

Instances are spread across underlying hardware (max 7 instances per group per AZ)

Pros: Minimizes simultaneous failure risk. Can span across AZ. EC2 instances are on different physical hardware

Cons: Limit of 7 per AZ per placement group

Best for apps with high availability needed, or critical applications where failures must be isolated.

Question 4

Describe partition placement groups, their pros/cons, and when they should be used

Answer 4

Spreads instances across many different partitions within an AZ. Scales to 100s of EC2 instances per group.

Pros: Distributed amongst many racks, so protected against rack failure. Can span multiple AZs. Up to 100s of EC2 instances.

Cons:

Best for large apps that can be partition aware. Big data applications.

Question 5

Describe an Elastic Network Interface (ENI)

Answer 5

Logical component in a VPC that represents a virtual network card.

Question 6

True of False:

Elastic Network Interfaces (ENI) are bound to a specific availability zone.

Answer 6

True.

Question 7

Describe EC2 Hibernate and best use cases

Answer 7

Space is allocated on the root volume to store the instance memory (RAM). To use hibernation, the root volume must be an encrypted EBS volume.

Use cases: long-running processing, saving the RAM state, services that take time to initialize

Question 8

What is EC2 Nitro?

Answer 8

The underlying platform for the next gen of EC2 instances. It has new virtualization technology, and allows for better performance.

Higher speed EBS IOPS - up to 64,000
(max 32,000 EBS IOPS on non-nitro)

+ better underlying security & better networking options

Question 9

What type of instances are using EC2 Nitro?

Answer 9

Any virtualized instances are using nitro,..
a1, c5, c6, d3, g4, i3, m5
bare metal

Question 10

When might you want to specify CPU options to decrease the number of CPU cores?

Answer 10

To decrease licensing costs where bill is based on the number of cores used.

Question 11

When might you want to decrease the number of threads per core?

Answer 11

For high performance computing (HPC) workloads

Question 12

Describe EC2 capacity reservations?

Answer 12

Reservations ensure you have capacity when it’s needed. Specifies AZ (only one), number of instances to reserve, and instance attributes.

Capacity access is immediate, you get billed as soon as it starts.

Can combine with reserved instances and savings plans for cost saving.

Question 13

You have launched an EC2 instance that will host a NodeJS application. After installing all the required software and configured your application, you noted down the EC2 instance public IPv4 so you can access it. Then, you stopped and then started your EC2 instance to complete the application configuration. After restart, you can’t access the EC2 instance, and you found that the EC2 instance public IPv4 has been changed. What should you do to assign a fixed public IPv4 to your EC2 instance?

Answer 13

Allocate an elastic IP and assign it to your instance. Elastic IP is a public IPv4 that you own as long as you want and you can attach it to one EC2 instance at a time.

Question 14

Spot Fleet is a set of Spot Instances and optionally…

Answer 14

On-demand instances.

Spot Fleet is a set of Spot Instances and optionally On-demand Instances. It allows you to automatically request Spot Instances with the lowest price.

Question 15

You have an application performing big data analysis hosted on a fleet of EC2 instances. You want to ensure your EC2 instances have the highest networking performance while communicating with each other. Which EC2 Placement Group should you choose?

Answer 15

Cluster Placement Group

Cluster Placement Groups place your EC2 instances next to each other which gives you high-performance computing and networking.

Question 16

You have a critical application hosted on a fleet of EC2 instances in which you want to achieve maximum availability when there’s an AZ failure. Which EC2 Placement Group should you choose?

Answer 16

Spread Placement Group

Spread Placement Group places your EC2 instances on different physical hardware across different AZs.

Question 17

True or False

Elastic Network Interface (ENI) can be attached to EC2 instances in another AZ.

Answer 17

False.

Elastic Network Interfaces (ENIs) are bounded to a specific AZ. You can not attach an ENI to an EC2 instance in a different AZ.

Question 18

True or False

To enable EC2 Hibernate, EC2 instance root volume type must be an EBS volume.

Answer 18

True.

To enable EC2 Hibernate, the EC2 Instance Root Volume type must be an EBS volume and must be encrypted to ensure the protection of sensitive content.