A Cantrill - EC2 Basics & Advanced

Question 1

Can you use EBS (Elastic Block Store) in multiple AZs?

Answer 1

No. EBS is limited to ONE AZ only

Question 2

What type of storage is EBS?

Answer 2

EBS is a persistent data storage type.

EBS backups are called Snapshots which backup to S3.

Question 3

How is EBS billed?

Answer 3

EBS is billed on a GB per month basis

Question 4

Instance stores MUST be attached to an EC2 at launch, T or F?

Answer 4

True. Instance stores MUST be attached to an EC2 at launch.

Question 5

What type of storage is Instance Store?

Answer 5

Ephemeral. If the instance is stopped or moves hosts, the instance datastore is lost.

Question 6

What is the pricing for instance store?

Answer 6

It is included in the price of your EC2 instance.

Question 7

What type of backups are EBS Snapshots?

Answer 7

Incremental volume copies to S3.

Question 8

what is the difference between restarting an EC2 AND “stopping and starting” an EC2?

Answer 8

-Restarting an EC2, the EC2 will stay on its host
-Stopping and starting an EC2, the EC2 will move hosts

Question 9

What kind of a key is used for each EBS volume? Default KMS key or single unique DEK?

Answer 9

Each volume uses 1 unique DEK. And these snapshots and future volumes will use the SAME DEK

Question 10

Every EC2 has at least one __?

Answer 10

ENI.
All EC2s need at least 1 ENI.

Question 11

All ENIs have what ?

Answer 11

MAC Address and a primary IPv4 IP. The IPs are on the ENI, NOT the actual EC2

Question 12

What happens to an IPv4 public IP when the EC2 is Stopped & Started?
What can be done to prevent a public IPv4 address from changing on an EC2?

Answer 12

-IPv4 public IPs are dynamic, so when you stop and start the EC2, the Public IP WILL change.
-Assign the EC2 an Elastic IP

Question 13

AMI work only in 1 region (t or f)?

Answer 13

AMIs work in only one region. But can be copied into a other regions.

Question 14

What is AMI baking?

Answer 14

Creating an AMI from configured AMI plus an application loaded automatically

Question 15

Are AMIs editable?

Answer 15

No, once an AMI is created you cannot change it. Need to make a new AMI

Question 16

If an AMI snapshot is copied over to another Region, is it the same AMI ?

Answer 16

When an AMI snapshot is copied over to another region, the new AMI is a different AMI. Same data but it is a different ID

Question 17

If a company is moving off regular servers (EC2s) and onto serverless or container architecture (Lambda, Fargate) what should they utilize to save $?

Answer 17

EC2 savings plan can be a good tool for a company moving off ec2s

Question 18

What service can be used to automatically recover EC2s that fail status checks ?

Answer 18

CloudWatch alarms can monitor the EC2 and automatically recover the instance if it becomes impaired due to an underlying hardware failure or a problem that requires AWS involvement to repair.

Question 19

What is the instance metadata address inside ALL instances?

Answer 19

http://169.254.169.254
http://169.254.169.254/latest/meta-data

Question 20

What kind of use-case suits using IO1 EBS volumes?

Answer 20

When Maximum Consistent IOPS is a priority and data is important

Question 21

What is the limit of size for user data in EC2?

Answer 21

Data size limit for user data is 16KB

Question 22

What is EC2 instance role?

Answer 22

Allow EC2 instances to securely interact with other AWS services without the need for manually managing API keys or credentials

Question 23

What IAM feature allows Lambda to interact with other AWS services?

Answer 23

Lambda Execution Roles: Provide permissions for Lambda functions to interact with other AWS services.

Question 24

Where is Parameter Store located? (what service)

Answer 24

Parameter Store is located in AWS Systems Manager.

Question 25

What is the advantage of Cluster Placement Groups?

Answer 25

Performance. EC2s are always in the same rack, SOMETIMES on the same host.

**One AZ only

Recomended that same type is launched. AND VERY recommended to launch at the same time

Question 26

What is the Advantage of Spread Placement Groups?

Answer 26

Resilience, infrastructure isolation. Each instance has its own rack and power source.

Use Case: Small # of critical instances that need to be kept isolated from each other

Question 27

What is the Advantage of Partition Placement Groups?

Answer 27

designed for huge scale parallel processing systems.

Topology Awareness. More control than Spread. 7 Partitions per AZ

Question 28

What is the difference between Spread and Partition placement groups?

Question 29

If you run a large application which uses 100’s of EC2 instances and it needs exposure to physical location for performance and availability reasons. Which placement group should you use?

Answer 29

Partition placement group

Question 30

How can permissions be provided to an application running in EC2 using best practices?

Answer 30

Instance Profile and IAM role.

Question 31

How many AZs can be used by a cluster placement group?

Answer 31

cluster placement group can utilize ONE AZ only

Question 32

How many instances can be within a spread placement group?

Answer 32

7 Instances per AZ

Question 33

What is the cost of each EC2 running on a dedicated host?

Answer 33

There is no cost for EC2s on a dedicated host, only the cost of the HOST itself.