EC2 Placement Groups Flashcards
What is an EC2 Placement Group?
Placement Groups are logical groupings or clusters of instances in an AWS region
What are the three types of EC2 Placement Groups?
- Clustered
- Spread
- Partitioned
What is a Clustered Placement Group?
A grouping of EC2 instances within a single availability zone
What is the recommended use case for a clustered placement group?
- Apps that need low latency, high throughput, or both
Can any type of EC2 instance be launched into a placement group?
No, only certain instance types can be launched into a placement group.
What is a Spread Placement Group?
- A group of EC2 instances that are placed on distinct underlying hardware.
- Think individual instances
What is the recommended use case for spread placement groups?
- Apps with a small number of critical instances that should be kept separate from one another
What is a Partitioned Placement Group?
- 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)
Can you have a clustered placement group spanning multiple AZs?
No
What are the namespace rules for EC2 Placement Groups?
The name you specify for a placement group must be unique within your AWS account
Can you put instances of different types in the same clustered placement group?
Yes, but AWS recommends against it.
Can you merge two placement groups?
No.
Can you move an existing EC2 instance into a placement group?
- 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.
How, using the console, can I move an EC2 instance into a placement group?
You can’t yet
What is the limit on the number of running instances per AZ in a Spread Placement Group?
7
