Cluster Placement Group Rules and Limitations

The following rules apply to Cluster Placement Groups

• Multiple Availability Zones cannot be covered by a cluster placement group. Cluster Placement Groups are limited to a single Availability Zone within a Region, so all instances within a Cluster Placement Group must reside in the same Availability Zone.
• The slower of the two instances in a cluster placement group has a limit on the maximum network throughput speed of traffic between them. Select an instance type with network connectivity that satisfies your needs if your applications have high throughput requirements.
• A cluster placement group can launch different instance kinds. This lessens the possibility that the necessary capacity will be accessible for your launch to be successful, though. All instances in a cluster placement group should be of the same instance type, per our recommendation.
• Not all EC2 instance types are supported in Cluster Placement Groups. For example, T2 and T3 instances are not supported.

Guidelines when improved Networking is enabled

• A Cluster Placement Group’s instances can use up to 10 Gbps of single-flow bandwidth. For single-flow traffic, instances outside of a cluster placement group can use up to 5 Gbps.
• All available instance aggregate bandwidth can be used for traffic to and from Amazon S3 buckets located in the same Region when it is routed across the public IP address space or through a VPC endpoint. Instances within a Cluster Placement Group are connected to multiple high-bandwidth, low-latency networks, which provides improved network performance compared to other placement strategies.
• The Maximum Amount of network traffic that can be sent to the internet or over an AWS Direct Connect connection to on-premises resources is 5 Gbps.
• Cluster Placement Group names must be unique within a region and cannot be changed once created.

Pre-requisite: EC2

Placement groups are a mechanism used in Amazon Elastic Compute Cloud (EC2) for controlling the placement of instances in a cluster. They have some rules and limitations that you need to be aware of when using them.

Here are some of the rules and limitations of Placement Groups:

• General Rules and Limitations
• Cluster Placement Group Rules and Limitations
• Partition Placement Group Rules and Limitations
• Spread Placement Group Rules and Limitations