Which TWO options are valid ways to scale an Azure Functions app running on the Premium plan?
Configuring pre-warmed instances is a key feature of the Azure Functions Premium plan designed to mitigate cold start latency. By specifying a number of pre-warmed instances, the platform ensures that these instances are always running and ready to process incoming requests, significantly improving the responsiveness of your function app, especially after periods of inactivity. This is a direct and effective scaling strategy.
Why this answer
Pre-warmed instances in the Premium plan reduce cold start latency by keeping a specified number of instances always loaded and ready to handle requests. Option C is correct because the Premium plan allows you to set both minimum and maximum instance counts, giving you control over baseline capacity and scaling limits. These settings are configured in the function app's scale settings and are not available in the Consumption plan.
Exam trap
The trap here is that candidates confuse the Premium plan's scaling capabilities with the Consumption plan's, mistakenly thinking that options like disabling scale-to-zero or configuring queue-length-based scaling rules are directly configurable in the Premium plan, when in fact the Premium plan's scaling is automatic and only allows setting min/max instance counts and pre-warmed instances.