A PlacementGroup node supports different strategies to place Amazon EC2 instances.
When you launch a new Amazon EC2instance, the Amazon EC2 service attempts to place the instance in such a way that all of your instances are spread out across underlying hardware to minimize correlated failures. You can use placement groups to influence the placement of a group of interdependent instances to meet the needs of your workload.
Syntax
tosca.nodes.AWS.Compute.PlacementGroup
properties:
strategy: String
partition_count: Integer
tags: ListProperties
-
strategy -
The strategy to use to place Amazon EC2 instances.
Required: Yes
Type: String
Possible values: CLUSTER | PARTITION | SPREAD_HOST | SPREAD_RACK
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CLUSTER – packs instances close together inside an Availability Zone. This strategy enables workloads to achieve the low-latency network performance necessary for tightly-coupled node-to-node communication that is typical of high-performance computing (HPC) applications.
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PARTITION – spreads your instances across logical partitions such that groups of instances in one partition do not share the underlying hardware with groups of instances in different partitions. This strategy is typically used by large distributed and replicated workloads, such as Hadoop, Cassandra, and Kafka.
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SPREAD_RACK – places a small group of instances across distinct underlying hardware to reduce correlated failures.
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SPREAD_HOST – used only with Outpost placement groups. Places a small group of instances across distinct underlying hardware to reduce correlated failures.
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partition_count -
The number of partitions.
Required: Required only when
strategyis set toPARTITION.Type: Integer
Possible values: 1 | 2 |3 | 4 | 5 | 6 | 7
-
tags -
The tags that you can attach to the placement group resource.
Required: No
Type: List
Example
ExamplePlacementGroup:
type: tosca.nodes.AWS.Compute.PlacementGroup
properties:
strategy: "PARTITION"
partition_count: 5
tags:
- tag_key=tag_value