Background on OpenShift Infra nodes (TL;DR: customers can deploy control plane pieces on infra nodes and do not require licenses): https://access.redhat.com/solutions/5034771

These are described here in the docs: https://docs.openshift.com/container-platform/4.9/machine_management/creating-infrastructure-machinesets.html

At the bottom of the doc, there are instructions for moving components to infra nodes:

https://docs.openshift.com/container-platform/4.9/machine_management/creating-infrastructure-machinesets.html#moving-resources-to-infrastructure-machinesets

Several customers have requested to deploy OSSM control plane components on Infra nodes. This is something we'd like to provide, though need to be sure that we have documentation for this setup, similar to other components - and that those instructions work. 

While there is a related OSSM issue (https://issues.redhat.com/browse/OSSM-459), the work should be primarily a documentation task with some QE. Service Mesh already allows for control plane components to be placed on particular nodes. We don't document this in the context of OpenShift infra nodes yet though. The goal would be go have a section for Service Mesh that is similar to: https://docs.openshift.com/container-platform/4.9/machine_management/creating-infrastructure-machinesets.html#infrastructure-moving-monitoring_creating-infrastructure-machinesets.