VMSS

🔁 Auto-Scaling in Azure

Azure VM auto-scaling is supported through Virtual Machine Scale Sets (VMSS).

🌀 What is VMSS?

A Virtual Machine Scale Set allows you to:

• Automatically increase/decrease VM count based on demand.

• Distribute traffic using a load balancer.

• Ensure high availability.

⚙️ Configure Auto-scaling

1. Go to Virtual Machine Scale Sets

2. Click Create

3. Fill in basic info and choose the OS image

4. Enable Auto-scaling:

   • Metric-based (e.g., CPU > 75%)

   • Schedule-based (e.g., scale on weekends)

5. Attach to a Load Balancer (optional)

🧠 Example Auto-scale Rule

• Scale-out: If CPU > 70% for 10 min → Add 1 instance

• Scale-in: If CPU < 30% for 10 min → Remove 1 instance

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