EC2 Placement Groups

Question 1

What is an EC2 Placement Group?

Answer 1

Placement Groups are logical groupings or clusters of instances in an AWS region

Question 2

What are the three types of EC2 Placement Groups?

Answer 2

• Clustered
• Spread
• Partitioned

Question 3

What is a Clustered Placement Group?

Answer 3

A grouping of EC2 instances within a single availability zone

Question 4

What is the recommended use case for a clustered placement group?

Answer 4

• Apps that need low latency, high throughput, or both

Question 5

Can any type of EC2 instance be launched into a placement group?

Answer 5

No, only certain instance types can be launched into a placement group.

Question 6

What is a Spread Placement Group?

Answer 6

• A group of EC2 instances that are placed on distinct underlying hardware.
• Think individual instances

Question 7

What is the recommended use case for spread placement groups?

Answer 7

• Apps with a small number of critical instances that should be kept separate from one another

Question 8

What is a Partitioned Placement Group?

Answer 8

• EC2 divides each group into logical instances called partitions
• Each partition within a placement group has its own set of racks
• Each rack has its own network and power source
• No two partitions within a placement group share the same racks, allowing you to isolate the impact of hardware failure within your application
• Think multiple instances (per rack)

Question 9

Can you have a clustered placement group spanning multiple AZs?

Answer 9

No

Question 10

What are the namespace rules for EC2 Placement Groups?

Answer 10

The name you specify for a placement group must be unique within your AWS account

Question 11

Can you put instances of different types in the same clustered placement group?

Answer 11

Yes, but AWS recommends against it.

Question 12

Can you merge two placement groups?

Answer 12

No.

Question 13

Can you move an existing EC2 instance into a placement group?

Answer 13

• Yes, but before moving the instance, it must be in the stopped state.
• You can move or remove using CLI and SDK, but not the console yet.

Question 14

How, using the console, can I move an EC2 instance into a placement group?

Answer 14

You can’t yet

Question 15

What is the limit on the number of running instances per AZ in a Spread Placement Group?

Answer 15

7