A spread placement group places instances on distinct underlying hardware across multiple Availability Zones (or within a single AZ), providing the highest level of fault tolerance by isolating critical instances from each other.

A spread placement group distributes EC2 instances across distinct underlying hardware, ensuring that each instance runs on a separate rack with independent power and network connectivity. This provides the highest level of fault tolerance among placement group strategies, as a failure of one rack affects only that instance. Spread groups can span multiple Availability Zones, and within each AZ, you can launch up to 7 running instances per AZ. This limitation makes spread groups ideal for small-scale critical applications like master databases, bastion hosts, or core application servers that require maximum isolation.

Create and Use a Spread Placement Group

Spread Placement Group Characteristics

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Maximum of 7 running instances per Availability Zone
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Can span multiple Availability Zones, increasing total capacity (e.g., 7 instances in AZ-A and 7 in AZ-B)
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Provides the highest fault tolerance among placement group strategies
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Ideal for critical applications requiring physical hardware isolation
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Instances are placed on separate racks, each with independent power and network
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Reduces impact of hardware failures to a single instance

Best Use Cases

1
Master database nodes requiring high availability
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Bastion hosts or jump servers
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Critical microservices that must remain operational despite hardware failures
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Small-scale HA clusters (e.g., 3-node etcd or ZooKeeper)
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Instances running compliance workloads requiring physical separation