EC2 - Placement Groups Flashcards
What are Placement Groups?
They allow you to control the placement strategy of EC2 Instances
List the three types of Placement Groups?
Cluster
Spread
Partition
What is a Cluster placement group?
It compiles instances into a low-latency group in a single AZ
What are the pros of a Cluster placement group?
Low latency between instances and high bandwidth
What are the cons of a Cluster placement group?
If the AZ fails, all instances fail at the same time
Name two use cases for a Cluster placement group?
- Big Data jobs that need to be completed fast.
- Applications that need extremely low latency and high network throughput/
What is a Spread placement group?
Instances are spread across multiple hardware that span multiple AZ’s.
What are the pros of Spread placement groups?
Reduced risk of simultaneous failure as the instances are spread out.
What are the cons of Spread placement groups?
You are limited to 7 instances per AZ per placement group.
Name two use cases for a Spread placement group?
- Applications that need to maximise high availability.
- Critical applications where each instance must be isolated from potential failures of other instances.
What are Partition placement groups?
Instances are spread across multiple partitions. Partitions represent a rack within an AZ.
How many partitions can be setup per AZ?
Up to 7
True or False? Partitions are locked to a single AZ.
False. Partitions can span across multiple AZs within the same region.
How are instance failures reduced by using a Partition placement group?
Failure of a partition doesn’t affect another partition. The hardware in each partition isn’t shared with other racks.
How many instances can be run by using a Partition placement group?
Up to 100s of EC2 Instances.
What are the cons of using a Partition placement group?
A partition failure can affect many EC2 instances. However this won’t affect other partitions.
What is a use case for using a Partition placement group?
Big data applications e.g. Kafka
