For Multi-Arch Cluster Installation for IBM Z nothing it is not documented that Platform "none" is required to work. There should be a box with the restriction of the supported environment in the instruction.

    Documentation for Multi-Arch Compute 
https://docs.openshift.com/container-platform/4.16/post_installation_configuration/configuring-multi-arch-compute-machines/creating-multi-arch-compute-nodes-ibm-z-kvm.html

https://docs.openshift.com/container-platform/4.16/post_installation_configuration/configuring-multi-arch-compute-machines/creating-multi-arch-compute-nodes-ibm-z.html

https://docs.openshift.com/container-platform/4.16/post_installation_configuration/configuring-multi-arch-compute-machines/creating-multi-arch-compute-nodes-bare-metal.html#creating-multi-arch-compute-nodes-bare-metal

The following has restrictions but not really clear with the pre-requisuites.
https://docs.openshift.com/container-platform/4.16/post_installation_configuration/configuring-multi-arch-compute-machines/creating-multi-arch-compute-nodes-ibm-z-lpar.html

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