Availability Zones

[mathieu-benoit]

• https://docs.microsoft.com/en-us/azure/aks/availability-zones

• https://channel9.msdn.com/Shows/Azure-Friday/Preview-of-Availability-Zones-for-your-Kubernetes-cluster-in-Azure

• You can only enable availability zones when the cluster is created

• Availability zone settings can't be updated after the cluster is created. You also can't update an existing, non-availability zone cluster to use availability zones

• You can't disable availability zones for an AKS cluster once it has been created

• The node size (VM SKU) selected must be available across all availability zones

• Clusters with availability zones enabled require use of Azure Standard Load Balancers for distribution across zones

• Volumes that use Azure managed disks are currently not zonal resources. Pods rescheduled in a different zone from their original zone can't reattach their previous disk(s). It's recommended to run stateless workloads that don't require persistent storage that may come across zonal issues.

• Supported regions: https://docs.microsoft.com/en-us/azure/availability-zones/az-overview#services-support-by-region

• Cross AZ traffic is charged if you have very chatty services you may want to allocate them in one Zone

  • Affinity with Pods could be used to achieve this, see example here.

[mathieu-benoit]

Depends on Standard Load Balancer #42

[mathieu-benoit]

AZ now GA with AKS: https://aka.ms/aks/zones

[mathieu-benoit]

Done via #49