Hello Varsha Zutshi,
Thanks for your question.
AKS node pools must be comprised of Azure VMs. It is not possible to add a VM outside of AKS directly to an AKS cluster node pool.
Every agent node of a system or user node pool is a VM provisioned as part of Azure Virtual Machine Scale Sets and managed by the AKS cluster. See reference documents here:
https://video2.skills-academy.com/en-us/azure/aks/concepts-clusters-workloads#nodes
Please let me know if you have further questions.
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