In Amazon Web Services (AWS), a placement group is a logical grouping of instances within a single Availability Zone. It allows you to influence the placement of instances to meet specific requirements for your applications or workloads. By launching instances in a placement group, you can take advantage of low-latency networking and high-bandwidth connectivity between the instances.
Placement groups are commonly used for applications that benefit from low network latency and high network throughput. These include high-performance computing (HPC) clusters, big data analytics frameworks, and distributed file systems.
There are two types of placement groups available in AWS:
Cluster Placement Group: This type of placement group is designed for tightly coupled workloads that require low-latency networking. Instances within a cluster placement group are placed in close physical proximity to achieve the lowest possible network latency between them. However, the availability of cluster placement groups is limited to a single Availability Zone.
Spread Placement Group: Spread placement groups are suitable for critical applications that require high availability and are designed to minimize the risk of simultaneous failures. Instances within a spread placement group are placed on distinct underlying hardware to reduce the likelihood of correlated failures. Spread placement groups can span multiple Availability Zones within a region.
It's important to note that placement groups have certain limitations. For example, you cannot merge placement groups or move an existing instance into a placement group. Additionally, the availability of placement groups varies across different AWS regions.
By leveraging placement groups in AWS, you can optimize the performance and reliability of your applications by strategically placing instances in close proximity or across multiple underlying hardware components, depending on your specific requirements.
Check out this AWS Course to learn more.