Creating an App Service Plan

What Is an App Service Plan?#

An Azure App Service Plan defines the underlying compute and networking infrastructure on which your App Service applications run. Think of it as the container for resources:

• Plan = infrastructure (VMs, networking, scaling rules)
• App = your code running on top of that infrastructure

Multiple App Services (web apps, APIs, etc.) can share a single App Service Plan and its resources.

Pricing Tiers#

The pricing tier controls VM size, number of instances, and which features are available.

Exam tip: Free/Shared tiers share compute and network. Basic/Standard/Premium tiers get dedicated compute but share the network. Isolated gets dedicated compute and network.

Hosting Environment Types#

1. Shared (Multi-tenant)#

• Apps share compute and network with other customers
• Cheapest option; lowest performance and isolation
• Free and Shared tiers only

2. Dedicated#

• Your own dedicated VM worker nodes inside a shared scale unit
• Network is still shared with other tenants
• Most common production setup (Basic, Standard, Premium)

3. Isolated (Single-tenant)#

• Dedicated compute and networking
• App Service runs inside your own VNet (App Service Environment)
• Used for compliance, security-sensitive, and enterprise workloads

Region Scope#

• An App Service Plan is tied to a single Azure region
• Apps on the plan must be deployed in the same region
• You cannot move an App Service Plan between regions — you must recreate it

Scaling Concepts#

Scale Up (Vertical Scaling)#

Change the pricing tier to get a bigger VM:

S1 → P1V3  (more CPU, RAM, storage, features)

Use when: your app needs more power per instance.

Scale Out (Horizontal Scaling)#

Increase the number of running instances:

1 instance → 5 instances

Options:

• Manual — set a fixed number
• Rules-based — trigger on CPU %, memory, schedule
• Automatic (Preview) — platform-managed autoscale

Use when: traffic increases and you need high availability.

Exam tip: Scale up = bigger machine. Scale out = more machines.

Important Features by Tier#

Real-World Decision Factors#

When choosing a plan tier, consider:

• Compute — how CPU/memory-intensive is your workload?
• Traffic — do you need autoscaling for variable load?
• Networking — do you need VNet integration or private access?
• Compliance/Security — isolated environment required? → Isolated tier (ASE)
• Cost — dev/test can use Basic; production typically uses Standard or Premium

Key Exam Takeaways#

• App Service Plan = compute infrastructure; App Service = your code
• Multiple apps can share one plan and split its resources
• Pricing tier determines available features, not just cost
• Scale up = change tier (bigger machine)
• Scale out = increase instance count (more machines)
• Isolated tier = full single-tenant isolation inside a VNet (App Service Environment)
• Plan is region-bound; apps must be in the same region

Quick Revision Cheat Sheet#

Plan = infrastructure
App = runs on plan
Tiers: Free → Basic → Standard → Premium → Isolated
Scale UP = change tier
Scale OUT = increase instances
Region-bound
Multiple apps can share one plan
Isolated = single-tenant + VNet = App Service Environment

Reference Documentation#

• App Service Plan overview and pricing
• Scale up an App Service app
• Autoscale configuration in Azure Monitor
• App Service Environment (Isolated tier)