Question

A company runs a stateless web API on a Virtual Machine Scale Set (VMSS) behind Azure Load Balancer. The deployment team wants to release new application versions with zero downtime and the ability to instantly roll back if error rates spike after a release. They also want to avoid maintaining double the compute capacity permanently. Which deployment strategy should the architect recommend?

Accepted Answer

Deploy a blue-green setup by provisioning a second identical VMSS and switching the load balancer backend pool, decommissioning the old scale set after validation.

Answer

Use VMSS rolling upgrades, which update instances in batches while the load balancer keeps healthy instances in rotation.

Answer

Enable VMSS automatic OS image upgrades so the platform replaces instances as new images become available.

Answer

Configure Azure App Service deployment slots and swap the staging slot into production.