Placement Groups for EC2 instances

This section provides an overview of Placement Groups in EC2.

To optimize your workload's performance, you can arrange multiple EC2 instances within a placement group, which influences how they are allocated within AWS's infrastructure. Depending on the specific needs of your workload, you can choose from one of the following placement strategies:

1. Cluster:

This strategy groups instances closely within a single Availability Zone, enabling ultra-low latency communication between them. It’s ideal for workloads requiring high-speed interactions between instances, like those found in high-performance computing (HPC) applications.

2. Partition:

This strategy spreads your instances across different logical partitions, ensuring that instances in one partition are isolated from those in another. This means that they do not share the same underlying hardware, making it a good choice for large-scale, distributed applications such as Hadoop, Cassandra, or Kafka, where minimizing the risk of simultaneous failures across instances is important.

3. Spread:

This strategy places each instance on separate physical hardware, reducing the likelihood of simultaneous failures. It's especially useful for small-scale workloads where resilience and fault tolerance are critical.

Note:

Using a placement group is optional. If you don’t specify one, EC2 will automatically attempt to distribute your instances across the available hardware to minimize the risk of correlated failures, where multiple instances could be affected by the same underlying hardware issue.