Azure Virtual Machine Scale Sets Documentation

Azure Virtual Machine Scale Sets

Virtual Machine Scale Sets (VMSS) allow you to deploy and manage a set of identical, load-balanced virtual machines. They simplify the deployment and management of a large number of VMs, providing high availability and scalability for your applications.

What are Virtual Machine Scale Sets?

VMSS enables you to automatically scale your virtual machines in or out manually or in response to detected demand or a schedule. This ensures that you have the right number of VMs available to handle your application load, improving performance and availability.

Key Features

Automatic Scaling: Define rules to automatically adjust the number of VM instances based on metrics like CPU usage, network traffic, or custom metrics.
High Availability: Distribute VM instances across multiple fault domains and update domains to ensure resilience.
Automated Orchestration: Manage VM lifecycle, including upgrades, patching, and deployments, with automated processes.
Load Balancing Integration: Seamlessly integrate with Azure Load Balancer or Application Gateway to distribute incoming traffic across your VM instances.
Customizable Images: Deploy VMs from custom VM images or Marketplace images.

Use Cases

Web server farms requiring elastic scaling.
Batch processing and high-performance computing (HPC) workloads.
Microservices architectures where instances need to scale independently.
Applications requiring a consistent deployment and management experience for multiple identical servers.

Creating a Virtual Machine Scale Set

You can create a VMSS using various methods:

Azure Portal: A user-friendly graphical interface for creating and managing resources.
Azure CLI: A powerful command-line tool for automating Azure deployments.
Azure PowerShell: Another scripting option for managing Azure resources.
ARM Templates / Bicep: Infrastructure as Code (IaC) for declarative deployment.

Example using Azure CLI:

az vmss create \
  --resource-group myResourceGroup \
  --name myScaleSet \
  --image UbuntuLTS \
  --vm-sku Standard_DS1_v2 \
  --instance-count 3 \
  --upgrade-policy-mode automatic \
  --admin-username azureuser \
  --generate-ssh-keys
            

Configuring Scaling

To configure automatic scaling, you can set up scale-in and scale-out rules based on performance metrics.

Note: Ensure your application is designed to be stateless or to handle state externally for effective scaling.

Managing Scale Sets

VMSS provides operations to:

Manually scale the number of instances.
Perform rolling upgrades of VM instances.
Re-image VM instances to the latest model.
Troubleshoot instance issues.

For more detailed information, explore the official Azure Virtual Machine Scale Sets documentation.