1---2name: azure-vm-scalesets3description: Expert knowledge for Azure Virtual Machine Scale Sets development including troubleshooting, best practices, decision making, architecture & design patterns, limits & quotas, security, configuration, integrations & coding patterns, and deployment. Use when configuring autoscale, standby pools, Spot mixes, disk encryption, or Shared Image Gallery images, and other Azure Virtual Machine Scale Sets related development tasks. Not for Azure Virtual Machines (use azure-virtual-machines), Azure Kubernetes Service (AKS) (use azure-kubernetes-service), Azure Container Instances (use azure-container-instances), Azure App Service (use azure-app-service).4---5# Azure Virtual Machine Scale Sets Skill67This 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.89## How to Use This Skill1011> **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 file1213This skill requires **network access** to fetch documentation content:14- **Preferred**: Use `mcp_microsoftdocs:microsoft_docs_fetch`. Returns Markdown.15- **Fallback**: Use `WebFetch`. Returns Markdown.1617## Category Index1819| Category | Lines | Description |20|----------|-------|-------------|21| Troubleshooting | L33-L39 | Diagnosing and fixing issues with VMSS instance mix, standby pools behavior, and autoscale (rules, scaling delays, capacity mismatches, and common error scenarios). |22| Best Practices | L40-L45 | Configuring rolling upgrades for VM scale sets, tuning MaxSurge settings, and strategies to minimize downtime and maintain high availability during production updates. |23| Decision Making | L46-L62 | 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. |24| Architecture & Design Patterns | L63-L67 | 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 |25| Limits & Quotas | L68-L73 | Limits, quotas, and behaviors of VM Scale Sets, including placement groups, max instance counts, capacity constraints, and how scaling and distribution work under these limits. |26| Security | L74-L85 | 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. |27| Configuration | L86-L129 | Configuring VM Scale Sets: templates, networking, disks, images, zones, upgrades, autoscale, repairs, standby pools, instance mix/protection, maintenance, and CLI/PowerShell/API management. |28| Integrations & Coding Patterns | L130-L135 | Configuring VM scale set standby pools with Log Analytics for monitoring and integrating scale sets with Azure DSC extension for automated configuration management. |29| Deployment | L136-L142 | Creating VM scale sets from generalized/specialized Shared Image Gallery images, migrating flexible sets to zonal, and deploying apps onto scale set instances. |3031### Troubleshooting32| Topic | URL |33|-------|-----|34| FAQ and troubleshooting for VM scale set instance mix | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/instance-mix-faq-troubleshooting |35| FAQ and troubleshooting for VM scale set standby pools | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/standby-pools-faq |36| Troubleshoot autoscale issues in Azure VM scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-troubleshoot |3738### Best Practices39| Topic | URL |40|-------|-----|41| 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 |42| Use MaxSurge rolling upgrades to improve uptime | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-maxsurge |4344### Decision Making45| Topic | URL |46|-------|-----|47| Apply Azure Hybrid Benefit to Linux scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/azure-hybrid-benefit-linux |48| 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 |49| Decide when to use instance mix in VM scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/instance-mix-overview |50| Compare Uniform and Flexible VMSS APIs | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/orchestration-modes-api-comparison |51| Use Spot Placement Score to plan deployments | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/spot-placement-score |52| Balance Spot and standard VMs with Priority Mix | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/spot-priority-mix |53| Use standby pools to reduce VM scale set latency | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/standby-pools-overview |54| Use Spot VMs in scale sets for cost savings | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/use-spot |55| 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 |56| 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 |57| 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 |58| 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 |59| 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 |6061### Architecture & Design Patterns62| Topic | URL |63|-------|-----|64| Use proximity placement groups with scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/proximity-placement-groups |6566### Limits & Quotas67| Topic | URL |68|-------|-----|69| Azure VM Scale Sets FAQs on limits and behavior | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-faq |70| 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 |7172### Security73| Topic | URL |74|-------|-----|75| Create and encrypt VM Scale Sets via ARM | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/disk-encryption-azure-resource-manager |76| Encrypt VM Scale Set disks with Azure CLI | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/disk-encryption-cli |77| Sequence extensions for VMSS disk encryption | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/disk-encryption-extension-sequencing |78| Configure Key Vault for VMSS disk encryption | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/disk-encryption-key-vault |79| Enable Azure Disk Encryption for VM Scale Sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/disk-encryption-overview |80| Encrypt VM Scale Set disks with PowerShell | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/disk-encryption-powershell |81| Apply built-in Azure Policy to VM Scale Sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/policy-reference |82| Configure RBAC permissions for VM scale set standby pools | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/standby-pools-configure-permissions |8384### Configuration85| Topic | URL |86|-------|-----|87| Alert on Automatic Instance Repairs ServiceState changes | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/alert-rules-automatic-repairs-service-state |88| Enable Automatic Zone Balance on scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/auto-zone-balance-enable |89| Use Automatic Zone Balance for VM Scale Sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/auto-zone-balance-overview |90| 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 |91| Configure instance mix for Azure VM scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/instance-mix-create |92| Update instance mix settings on Azure VM scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/instance-mix-update |93| Inspect instance mix configuration on VM scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/instance-mix-view |94| Enable resilient create and delete for scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/resilient-vm-create-delete |95| Create and configure standby pools for VM scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/standby-pools-create |96| 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 |97| 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 |98| 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 |99| Configure Spot instances in VM scale set standby pools | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/standby-pools-spot-instances |100| 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 |101| 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 |102| 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 |103| Configure automatic OS image upgrades for VMSS | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-automatic-upgrade |104| 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 |105| Sequence VM extensions in Azure scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-extension-sequencing |106| Configure Application Health extension for scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-health-extension |107| 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 |108| Configure instance protection on VM Scale Sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-instance-protection |109| Handle maintenance notifications for VM Scale Sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-maintenance-notifications |110| 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 |111| Manage VM Scale Sets with Azure PowerShell | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-manage-powershell |112| 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 |113| 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 |114| 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 |115| 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 |116| Configure networking for Azure VM Scale Sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-networking |117| 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 |118| 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 |119| 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 |120| 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 |121| 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 |122| 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 |123| Enable terminate notifications for scale set instances | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-terminate-notification |124| 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 |125| 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 |126| 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 |127128### Integrations & Coding Patterns129| Topic | URL |130|-------|-----|131| 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 |132| Integrate VM Scale Sets with Azure DSC extension | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-dsc |133134### Deployment135| Topic | URL |136|-------|-----|137| Create scale sets from generalized gallery images | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/instance-generalized-image-version |138| Create scale sets from specialized gallery images | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/instance-specialized-image-version |139| Migrate regional flexible scale sets to zonal sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/migrate-scale-set-flex-to-availability-zones |140| Deploy applications to VM Scale Set instances | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-deploy-app |
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