SLA for API Service
A formal SLA for the AKS API that's not simply based on the worker nodes (VM SLA). The reason behind this is that in some cases the component of the service that is the slowest or can become unresponsive is the API, not the deployed nodes, at least during preview testing. Also, if the API is not accessible for an extended period of time, the inability to deploy or update services on the cluster could impact business.
John Rusk commented
Is this what you're looking for? https://docs.microsoft.com/en-us/azure/aks/uptime-sla