You can use infrastructure machine sets to create machines that host only infrastructure components, such as the default router, the integrated container image registry, and the components for cluster metrics and monitoring. These infrastructure machines are not counted toward the total number of subscriptions that are required to run the environment.
For information about infrastructure nodes and which components can run on infrastructure nodes, see the "Red Hat OpenShift control plane and infrastructure nodes" section in the OpenShift sizing and subscription guide for enterprise Kubernetes document.
In a production deployment, it is recommended that you deploy at least three machine sets to hold infrastructure components. Both OpenShift Logging and {SMProductName} deploy Elasticsearch, which requires three instances to be installed on different nodes. Each of these nodes can be deployed to different availability zones for high availability. A configuration like this requires three different machine sets, one for each availability zone. In global Azure regions that do not have multiple availability zones, you can use availability sets to ensure high availability.
Use the sample machine set for your cloud.
Machine sets running on AWS support non-guaranteed Spot Instances. You can save on costs by using Spot Instances at a lower price compared to
On-Demand Instances on AWS. Configure Spot Instances by adding spotMarketOptions to the MachineSet YAML file.
Machine sets running on Azure support non-guaranteed Spot VMs. You can save on costs by using Spot VMs at a lower price compared to standard VMs on Azure. You can configure Spot VMs by adding spotVMOptions to the MachineSet YAML file.
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Note
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Machine sets running on Azure Stack Hub do not support non-guaranteed Spot VMs. |
Machine sets running on GCP support non-guaranteed preemptible VM instances. You can save on costs by using preemptible VM instances at a lower price
compared to normal instances on GCP. You can configure preemptible VM instances by adding preemptible to the MachineSet YAML file.
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See Node configuration management with machine config pools for more information on grouping infra machines in a custom pool.
After creating an infrastructure machine set, the worker and infra roles are applied to new infra nodes. Nodes with the infra role applied are not counted toward the total number of subscriptions that are required to run the environment, even when the worker role is also applied.
However, with an infra node being assigned as a worker, there is a chance user workloads could get inadvertently assigned to an infra node. To avoid this, you can apply a taint to the infra node and tolerations for the pods you want to control.
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See Controlling pod placement using the scheduler for general information on scheduling a pod to a node.
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See Moving resources to infrastructure machine sets for instructions on scheduling pods to infra nodes.
Some of the infrastructure resources are deployed in your cluster by default. You can move them to the infrastructure machine sets that you created.
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See the monitoring documentation for the general instructions on moving {product-title} components.