// Module included in the following assemblies:
//
// * machine_management/cluster_api_machine_management/cluster-api-about.adoc

:_mod-docs-content-type: REFERENCE
[id="capi-arch-resources_{context}"]
= Cluster API primary resources

[role="_abstract"]
The Cluster API consists of the following primary resources. For the Technology Preview of this feature, you must create some of these resources manually in the `openshift-cluster-api` namespace.

Cluster:: A fundamental unit that represents a cluster that is managed by the Cluster API.

Infrastructure cluster:: A provider-specific resource that defines properties that all of the compute machine sets in the cluster share, such as the region and subnets.

Machine template:: A provider-specific template that defines the properties of the machines that a compute machine set creates.

Machine set:: A group of machines.
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Compute machine sets are to machines as replica sets are to pods.
To add machines or scale them down, change the `replicas` field on the compute machine set custom resource to meet your compute needs.
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With the Cluster API, a compute machine set references a `Cluster` object and a provider-specific machine template.

Machine:: A fundamental unit that describes the host for a node.
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The Cluster API creates machines based on the configuration in the machine template.