I am getting a little confused on this based on the current documentation. The question is simple, does AKS support HA for master nodes?
From here it reads:
The AKS control plane components for your cluster are also spread across zones in the highest available configuration when you define the --zones parameter at cluster creation time.
From here it reads:
AKS provides a single-tenant control plane, with a dedicated API server, Scheduler, etc.
And from the documentation, the --zones parameter specifies that it's where agent nodes are placed.
So are master nodes HA across multi-az or not?
Yes, AKS provides HA for master nodes. This doc explains it well (https://docs.microsoft.com/en-us/azure/aks/operator-best-practices-multi-region). In AKS, it suggests to deploy nodes in multiple zones for disaster recovery.