Placement Groups

It is the strategy that we place the EC2 instance.

There are 3 strategies

1. Cluster

2. Spread

3. Partition

Cluster

It will places all EC2 instances in 1 AZ (Single AZ).

Pros

• Low network latency

Cons:

• Low High availability because If the AZ fails , all instances will fail.

Usecase:

• Big data needs to complete fast

• Application need low latency

Spread

It will places all instances on serparate AZ.

Pros

• can span across AZ

• reduce risk failure

Cons:

• limited 7 instance per AZ

Usecase

• application that needs to maximize high availablity

Partition

It is similarto Spread but It can span across multiple AZ in the same region. The instance in a partion do not shre racks with other partition.

Pros

• can span multiple AZ in same region

• reduce risk failure

Cons

• one partition fail all of instance in that partition will fail

Usecase

• Kafka, Cassandra