Azure Virtual Machine Scale Sets Skill

This skill provides expert guidance for Azure Virtual Machine Scale Sets. Covers troubleshooting, best practices, decision making, architecture & design patterns, limits & quotas, security, configuration, integrations & coding patterns, and deployment. It combines local quick-reference content with remote documentation fetching capabilities.

How to Use This Skill

> IMPORTANT for Agent: Use the Category Index below to locate relevant sections. For categories with line ranges (e.g., L35-L120), use read_file with the specified lines. For categories with file links (e.g., [security.md](security.md)), use read_file on the linked reference file

> IMPORTANT for Agent: If metadata.generated_at is more than 3 months old, suggest the user pull the latest version from the repository. If mcp_microsoftdocs tools are not available, suggest the user install it: Installation Guide

This skill requires network access to fetch documentation content:

• Preferred: Use mcp_microsoftdocs:microsoft_docs_fetch with query string from=learn-agent-skill. Returns Markdown.
• Fallback: Use fetch_webpage with query string from=learn-agent-skill&accept=text/markdown. Returns Markdown.

Category Index

| Category | Lines | Description | |----------|-------|-------------| | Troubleshooting | L37-L43 | Diagnosing and fixing issues with VMSS instance mix, standby pools behavior, and autoscale (rules, scaling delays, capacity mismatches, and common error scenarios). | | Best Practices | L44-L49 | Configuring rolling upgrades for VM scale sets, tuning MaxSurge settings, and strategies to minimize downtime and maintain high availability during production updates. | | Decision Making | L50-L66 | Guidance on choosing VMSS orchestration/upgrade modes, autoscale, Spot vs standard/priority mix, fault domains, standby pools, and cost-optimized configurations for different workload patterns. | | Architecture & Design Patterns | L67-L71 | Designing scale sets with proximity placement groups to minimize latency, improve performance, and ensure VMs are co-located for tightly coupled or high-performance workloads | | Limits & Quotas | L72-L77 | Scale set capacity, instance, and resource limits; placement group behavior; scaling constraints; and how limits affect deployment, availability, and distribution of VMs. | | Security | L78-L89 | Encrypting VMSS disks (CLI, PowerShell, ARM), configuring Azure Disk Encryption with Key Vault and extensions, and securing scale sets via Azure Policy and RBAC for standby pools. | | Configuration | L90-L133 | Configuring VM Scale Sets: templates, networking, disks, images, zones, upgrades, autoscale, repairs, standby pools, instance mix/protection, maintenance, and CLI/PowerShell/API management. | | Integrations & Coding Patterns | L134-L139 | Configuring VM scale set standby pools with Log Analytics for monitoring and integrating scale sets with Azure DSC extension for automated configuration management. | | Deployment | L140-L146 | Creating VM scale sets from generalized/specialized Shared Image Gallery images, migrating flexible sets to zonal, and deploying/rolling out applications to scale set instances |

Troubleshooting

| Topic | URL | |-------|-----| | FAQ and troubleshooting for VM scale set instance mix | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/instance-mix-faq-troubleshooting | | FAQ and troubleshooting for VM scale set standby pools | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/standby-pools-faq | | Troubleshoot autoscale issues in Azure VM scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-troubleshoot |

Best Practices

| Topic | URL | |-------|-----| | Configure rolling upgrades for production scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-configure-rolling-upgrades | | Use MaxSurge rolling upgrades to improve uptime | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-maxsurge |

Decision Making

| Topic | URL | |-------|-----| | Apply Azure Hybrid Benefit to Linux scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/azure-hybrid-benefit-linux | | Migrate workloads to Flexible orchestration scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/flexible-virtual-machine-scale-sets-migration-resources | | Decide when to use instance mix in VM scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/instance-mix-overview | | Compare Uniform and Flexible VMSS APIs | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/orchestration-modes-api-comparison | | Use Spot Placement Score to plan deployments | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/spot-placement-score | | Balance Spot and standard VMs with Priority Mix | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/spot-priority-mix | | Use standby pools to reduce VM scale set latency | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/standby-pools-overview | | Use Spot VMs in scale sets for cost savings | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/use-spot | | Select autoscale options for Azure VM scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-autoscale-overview | | Design and choose features for VM Scale Sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-design-overview | | Choose and configure fault domains for scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-manage-fault-domains | | Choose VM scale set orchestration mode in Azure | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-orchestration-modes | | Choose upgrade policy modes for VM Scale Sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-upgrade-policy |

Architecture & Design Patterns

| Topic | URL | |-------|-----| | Use proximity placement groups with scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/proximity-placement-groups |

Limits & Quotas

| Topic | URL | |-------|-----| | Reference limits and behaviors for VM Scale Sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-faq | | Understand placement groups and scale set capacity limits | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-placement-groups |

Security

| Topic | URL | |-------|-----| | Create and encrypt VM Scale Sets via ARM | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/disk-encryption-azure-resource-manager | | Encrypt VM Scale Set disks with Azure CLI | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/disk-encryption-cli | | Sequence extensions for VMSS disk encryption | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/disk-encryption-extension-sequencing | | Configure Key Vault for VMSS disk encryption | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/disk-encryption-key-vault | | Enable Azure Disk Encryption for VM Scale Sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/disk-encryption-overview | | Encrypt VM Scale Set disks with PowerShell | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/disk-encryption-powershell | | Apply built-in Azure Policy to VM Scale Sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/policy-reference | | Configure RBAC permissions for VM scale set standby pools | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/standby-pools-configure-permissions |

Configuration

| Topic | URL | |-------|-----| | Alert on Automatic Instance Repairs ServiceState changes | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/alert-rules-automatic-repairs-service-state | | Enable Automatic Zone Balance on scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/auto-zone-balance-enable | | Use Automatic Zone Balance for VM Scale Sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/auto-zone-balance-overview | | Define VM scale set configuration with ARM templates | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/flexible-virtual-machine-scale-sets-rest-api | | Configure instance mix for Azure VM scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/instance-mix-create | | Update instance mix settings on Azure VM scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/instance-mix-update | | Inspect instance mix configuration on VM scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/instance-mix-view | | Enable resilient create and delete for scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/resilient-vm-create-delete | | Create and configure standby pools for VM scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/standby-pools-create | | Retrieve standby pool and instance details for VM scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/standby-pools-get-details | | Understand and query standby pool health state in VM scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/standby-pools-health-state | | Get prediction results to size VM scale set standby pools | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/standby-pools-prediction-results | | Configure Spot instances in VM scale set standby pools | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/standby-pools-spot-instances | | Update or delete standby pools for Azure VM scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/standby-pools-update-delete | | Configure attached data disks for VM Scale Sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-attached-disks | | Configure automatic instance repairs for scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-automatic-instance-repairs | | Configure automatic OS image upgrades for VMSS | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-automatic-upgrade | | Change upgrade policy mode on existing scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-change-upgrade-policy | | Sequence VM extensions in Azure scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-extension-sequencing | | Configure Application Health extension for scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-health-extension | | Understand and use instance IDs in scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-instance-ids | | Configure instance protection on VM Scale Sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-instance-protection | | Handle maintenance notifications for VM Scale Sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-maintenance-notifications | | Manage VM Scale Sets using Azure CLI commands | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-manage-cli | | Manage VM Scale Sets with Azure PowerShell | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-manage-powershell | | Reference custom images in scale set templates | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-mvss-custom-image | | Use existing virtual networks in VMSS templates | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-mvss-existing-vnet | | Configure guest-metric autoscale for Linux VM scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-mvss-guest-based-autoscale-linux | | Author basic ARM templates for VM Scale Sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-mvss-start | | Configure networking for Azure VM Scale Sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-networking | | Perform manual instance upgrades in VM Scale Sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-perform-manual-upgrades | | Reimage virtual machines in a scale set | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-reimage-virtual-machine | | Configure custom metrics for rolling upgrades | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-rolling-upgrade-custom-metrics | | Configure scale-in policies for Azure VM scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-scale-in-policy | | Define scaling profiles for Azure VM scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-scaling-profile | | Set upgrade policy mode on VM Scale Sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-set-upgrade-policy | | Enable terminate notifications for scale set instances | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-terminate-notification | | Modify VM Scale Set model and configuration via APIs | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-upgrade-scale-set | | Configure VM Scale Sets with availability zones | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-use-availability-zones | | Configure and manage zone balancing in scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-zone-balancing |

Integrations & Coding Patterns

| Topic | URL | |-------|-----| | Integrate VM scale set standby pools with Azure Log Analytics | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/standby-pools-monitor-pool-events | | Integrate VM Scale Sets with Azure DSC extension | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-dsc |

Deployment

| Topic | URL | |-------|-----| | Create scale sets from generalized gallery images | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/instance-generalized-image-version | | Create scale sets from specialized gallery images | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/instance-specialized-image-version | | Migrate regional flexible scale sets to zonal | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/migrate-scale-set-flex-to-availability-zones | | Deploy applications to VM Scale Set instances | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-deploy-app |