IPs, EC2 placement groups, ENI, EC2 hibernate

Question 1

What is Elastic IP

Answer 1

an AWS static IP

Question 2

What is the default limit of Elastic IPs per account

Answer 2

5

Question 3

Should you use Elastic IPs

Answer 3

Avoid if possible, use DNS instead

Question 4

List the types of EC2 placement groups

Answer 4

Cluster, Spread, Partition

Question 5

Describe Cluster placement group

Answer 5

Places instances into a low-latency group in a single availability zone (single rack), pro: great network connectivity and throughput, con: single point of failure

Question 6

Describe Spread type placement group

Answer 6

spreads instances across different underlying hardware, can span across AZ
pro: minimize failure risk con: max 7 instances per AZ , app cannot be too big

Question 7

Describe partition placement group

Answer 7

spreads instances across many partitions(represents a rack),
pro: safe from rack failure. Use case: big data

Question 8

What is ENI?

Answer 8

Elastic Network Interface, logical component in a VPC, represents and virtual network card

Question 9

What attributes can an ENI have?

Answer 9

Primary private IPv4, one or more secondary IPv5, one Elastic IP, one public IP, one or more security groups, a MAC address.

Question 10

True or False, ENI can be bound to multiple
AZs

Answer 10

false, can only be bound to one AZ

Question 11

Why would you create and attach ENIs to different EC2s on the fly?

Answer 11

For failover