EC2 and Storage

Question 1

What is the point of EC2 Instance Roles?

Answer 1

They allow for the instance to perform API calls on behalf of the instance to other AWS resources (i.e. Calls to IAM or S3)

Question 2

What is the difference between the On-Demand and Reserved Instance options?

Answer 2

On-Demand has no up-front costs, and is payed for by the second. You have full control over its lifecycle.

Reserved Instances are physically the same as On-Demand, however a billing discount is applied and must have certain attributes applied.

Question 3

What are Spot Fleets?

Answer 3

Spot fleets are a set of Spot Instances + (optional) On-Demand instances that are managed by AWS. The Spot Fleet will try to meet the target capacity with price constraints.

We must define multiple launch pools.

Question 4

What is a storage optimized Instance?

Answer 4

Instances designed for workloads that require high, sequential read and write access to very large data sets.

Question 5

What are the three Placement Group strategies?

Answer 5

Cluster: Clusters instances into a low-latency group in a single AZ, same hardware, low-latency

Spread: Spreads instances across underlying hardware

Partition: Spreads instances across many different partitions within an AZ, such that groups in one partition do not share underlying hardware with groups of instances in another partition

Question 6

What is the max number of Partitions you can have per AZ for a Placement Group partition strategy?

Answer 6

Seven

Question 7

Why would you create your own ENIs?

Answer 7

When instances are deleted, the default ENIs are deleted with them. With the creation of our own ENIs, we get to move them to instances we need them to be attached to and assign certain IP Addresses.

Question 8

What is a Spot Instance?

Answer 8

Spot instances are instances that are ran when capacity is available and the spot price is lower than our maximum rates.

Question 9

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 9

Cluster Placement

Question 10

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 10

Spread

Question 11

Why would you use a Partition Placement strategy?

Answer 11

This is a good balance between High Performance and High Availability; we can have multiple instances in the same rack for High Performance and instances in other racks for High Availability.

Question 12

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

Answer 12

False. ENIs are bounded to a specific AZ

Question 13

What storage type must be used to enable EC2 Hibernate?

Answer 13

EBS. The data persisting in RAM is migrated to EBS when the instance is hibernated. Only works with GP and Provisioned IOPS

Question 14

How does EBS attach to an Instance?

Answer 14

Through a network drive. This allows us to attach and detach

Question 15

True or False: EBS can be bound across AZs?

Answer 15

False. If we want to move it across AZs, we need to create a snapshot and recreate it in another AZ

Question 16

If we want to move EBS volume across an AZ or Region, what can we do?

Answer 16

Create an EBS snapshot

Question 17

What is an AMI?

Answer 17

Amazon Machine Image. It provides the information needed to launch an Instance.

Question 18

Why would you use an EC2 Instance Store over an EBS volume?

Answer 18

The EC2 Instance Store will be more high performance than the EBS volume as it is physically located on the same disk

Question 19

What are the downsides on an EC2 Instance Store?

Answer 19

An Instance Store is lost under the following circumstances: underlying disk fails, instance stops, hibernated or terminates

We can also not transfer an Instance Store like we can an EBS Volume

Question 20

What volume types are provided by EBS?

Answer 20

General Purpose SSD, Provisioned IOPS SSD, Throughput Optimized HDD and Cold HDD

Question 21

If we need an EBS Volume type for intensive and frequent database workloads, which Volume type should we use?

Answer 21

Provisioned IOPS

Question 22

What two EBS Volume types can be Boot volumes?

Answer 22

General Purpose and Provisioned IOPS

Question 23

We want to attach an EBS to multiple instances. What can we do?

Answer 23

Use EBS Multi-Attach. Only works for Provisioned IOPS

Question 24

True or False: EFS can be in multi-AZ

Answer 24

True

Question 25

What is the difference between EFS and EBS

Answer 25

EBS will store data in the system in equal sized blocks. Allowing for faster retrieval. EFS has an extra layer consisting of a file system to process before accessing the data. EFS is also multi-AZ by default.

Question 26

You have just terminated an EC2 instance in us-east-1a, and its attached EBS volume is now available. Your teammate tries to attach it to an EC2 instance in us-east-1b but he can't. What is a possible cause for this?

Answer 26

EBS volumes are locked to an AZ

Question 27

You have launched an EC2 instance with two EBS volumes, Root volume type and the other EBS volume type to store the data. A month later you are planning to terminate the EC2 instance. What's the default behavior that will happen to each EBS volume?

Answer 27

The Root volume type will be deleted and the other EBS volume type will not be deleted

Question 28

What is EBS Multi-Attach?

Answer 28

Attaches the same EBS volume to multiple EC2 instances in the same AZ

Question 29

You would like to encrypt an unencrypted EBS volume attached to your EC2 instance. What should you do?

Answer 29

Create an EBS snapshot of your EBS volume. Copy the snapshot and with encryption. Then, use the encrypted snapshot to create a new EBS volume

Question 30

You would like to have a high-performance local cache for your application hosted on an EC2 instance. You don't mind losing the cache upon the termination of your EC2 instance. Which storage mechanism do you recommend as a Solutions Architect?

Answer 30

Instance Store

Question 31

You are running a high-performance database that requires an IOPS of 310,000 for its underlying storage. What do you recommend?

Answer 31

Use an EC2 Instance Store. EBS io2 has a max 256,000 IOPS and EBS io1 has a max 64,000 IOPS

Question 32

What are the two types of Spot Fleet requests?

Answer 32

Requests - If you configure the request type as request, it is only a one-time request. Spot Fleet does not attempt to replenish Spot Instances. Maintain - Spot Fleet will attempt to maintain capacity by automatically replenishing any interrupted Spot Instances.

Question 33

What is a Spot Instance Pool

Answer 33

A Spot Instance Pool is a set of unused Instances with the same instance type (e.g. m5.large) and AZ

Question 34

Can we attach and detach root volumes from EC2 instances?

Answer 34

Yes, we can https://serverfault.com/questions/588435/detatch-an-ebs-volume-from-one-instance-and-attach-to-another

Question 35

True or False: We can have multiple EBS volumes attached to a single EC2 instance

Answer 35

Yes

Question 36

What is EBS Snapshot Archive?

Answer 36

EBS Snapshot Archive moves a snapshot to an "archive tier" within S3 which is 75% cheaper. However, restoring from the snapshot takes within 24 to 72 hours

Question 37

Where do EBS snapshots reside?

Answer 37

In S3 storage

Question 38

How can we prevent accidental deletions of EBS snapshots?

Answer 38

We can setup rules to send deleted snapshots in a "recycle bin". Recycle Bin is an AWS resource

Question 39

We need to recover an EBS snapshot with no latency when needed. What can we do?

Answer 39

Put it in Fast Snapshot Restore. Costs more money

Question 40

Which has better IOPS performance, Instance store or Block storage?

Answer 40

Instance Store usually has better IOPS performance; that's because they are a hardware disk attached to the EC2 instance

Question 41

We need a high-performance storage option for an EC2 instance for cache and buffering data. What can we use?

Answer 41

EC2 Instance Store

Question 42

How many EC2 instances can be connected to one EBS Multi-Attach?

Answer 42

Up to 16

Question 43

What are EFS throughput modes?

Answer 43

Bursting: Throughput allowance is increased as workload increases (if credits are available). Depends on size of the file system Elastic: Scales up or down to meet throughput needs; not dependent on credits Provisioned: Users specify the level of throughput regardless of file system size or credits