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, instance mix, disk encryption with Key Vault, or rolling upgrades, and other Azure Virtual Machine Scale Sets related development tasks. Not for Azure Virtual Machines (use azure-virtual-machines), SQL Server on Azure Virtual Machines (use azure-sql-virtual-machines), Azure Kubernetes Service (AKS) (use azure-kubernetes-service), Azure Container Instances (use azure-container-instances).4---5# Azure Virtual Machine Scale Sets Skill
6
7This 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.
8
9## How to Use This Skill
10
11> **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
12
13> **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](https://github.com/MicrosoftDocs/mcp/blob/main/README.md)
14
15This skill requires **network access** to fetch documentation content:
16- **Preferred**: Use `mcp_microsoftdocs:microsoft_docs_fetch` with query string `from=learn-agent-skill`. Returns Markdown.
17- **Fallback**: Use `fetch_webpage` with query string `from=learn-agent-skill&accept=text/markdown`. Returns Markdown.
18
19## Category Index
20
21| Category | Lines | Description |
22|----------|-------|-------------|
23| 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). |
24| 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. |
25| Decision Making | L50-L66 | Guidance on choosing VM scale set modes, features, autoscale, Spot vs standard, instance mix, fault domains, upgrade policies, Hybrid Benefit, and migration/latency tradeoffs. |
26| 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 |
27| 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. |
28| 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. |
29| 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. |
30| 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. |
31| 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 |
32
33### Troubleshooting
34| Topic | URL |
35|-------|-----|
36| FAQ and troubleshooting for VM scale set instance mix | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/instance-mix-faq-troubleshooting |
37| FAQ and troubleshooting for VM scale set standby pools | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/standby-pools-faq |
38| Troubleshoot autoscale issues in Azure VM scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-troubleshoot |
39
40### Best Practices
41| Topic | URL |
42|-------|-----|
43| 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 |
44| Use MaxSurge rolling upgrades to improve uptime | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-maxsurge |
45
46### Decision Making
47| Topic | URL |
48|-------|-----|
49| Apply Azure Hybrid Benefit to Linux scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/azure-hybrid-benefit-linux |
50| 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 |
51| Decide when to use instance mix in VM scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/instance-mix-overview |
52| Compare Uniform and Flexible VMSS APIs | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/orchestration-modes-api-comparison |
53| Use Spot Placement Score to plan deployments | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/spot-placement-score |
54| Balance Spot and standard VMs with Priority Mix | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/spot-priority-mix |
55| Use standby pools to reduce VM scale set latency | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/standby-pools-overview |
56| Use Spot VMs in scale sets for cost savings | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/use-spot |
57| 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 |
58| 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 |
59| 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 |
60| Choose orchestration mode for Azure VM scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-orchestration-modes |
61| 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 |
62
63### Architecture & Design Patterns
64| Topic | URL |
65|-------|-----|
66| Use proximity placement groups with scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/proximity-placement-groups |
67
68### Limits & Quotas
69| Topic | URL |
70|-------|-----|
71| Reference limits and behaviors for VM Scale Sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-faq |
72| 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 |
73
74### Security
75| Topic | URL |
76|-------|-----|
77| Create and encrypt VM Scale Sets via ARM | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/disk-encryption-azure-resource-manager |
78| Encrypt VM Scale Set disks with Azure CLI | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/disk-encryption-cli |
79| Sequence extensions for VMSS disk encryption | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/disk-encryption-extension-sequencing |
80| Configure Key Vault for VMSS disk encryption | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/disk-encryption-key-vault |
81| Enable Azure Disk Encryption for VM Scale Sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/disk-encryption-overview |
82| Encrypt VM Scale Set disks with PowerShell | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/disk-encryption-powershell |
83| Apply built-in Azure Policy to VM Scale Sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/policy-reference |
84| Configure RBAC permissions for VM scale set standby pools | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/standby-pools-configure-permissions |
85
86### Configuration
87| Topic | URL |
88|-------|-----|
89| Alert on Automatic Instance Repairs ServiceState changes | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/alert-rules-automatic-repairs-service-state |
90| Enable Automatic Zone Balance on scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/auto-zone-balance-enable |
91| Use Automatic Zone Balance for VM Scale Sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/auto-zone-balance-overview |
92| 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 |
93| Configure instance mix for Azure VM scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/instance-mix-create |
94| Update instance mix settings on Azure VM scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/instance-mix-update |
95| Inspect instance mix configuration on VM scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/instance-mix-view |
96| Enable resilient create and delete for scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/resilient-vm-create-delete |
97| Create and configure standby pools for VM scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/standby-pools-create |
98| 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 |
99| 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 |
100| 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 |
101| Configure Spot instances in VM scale set standby pools | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/standby-pools-spot-instances |
102| 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 |
103| 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 |
104| 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 |
105| Configure automatic OS image upgrades for VMSS | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-automatic-upgrade |
106| 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 |
107| Sequence VM extensions in Azure scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-extension-sequencing |
108| Configure Application Health extension for scale sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-health-extension |
109| 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 |
110| Configure instance protection on VM Scale Sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-instance-protection |
111| Handle maintenance notifications for VM Scale Sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-maintenance-notifications |
112| 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 |
113| Manage VM Scale Sets with Azure PowerShell | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-manage-powershell |
114| 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 |
115| 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 |
116| 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 |
117| 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 |
118| Configure networking for Azure VM Scale Sets | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-networking |
119| 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 |
120| 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 |
121| 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 |
122| 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 |
123| 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 |
124| 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 |
125| Enable terminate notifications for scale set instances | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-terminate-notification |
126| 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 |
127| 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 |
128| 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 |
129
130### Integrations & Coding Patterns
131| Topic | URL |
132|-------|-----|
133| 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 |
134| Integrate VM Scale Sets with Azure DSC extension | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-dsc |
135
136### Deployment
137| Topic | URL |
138|-------|-----|
139| Create scale sets from generalized gallery images | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/instance-generalized-image-version |
140| Create scale sets from specialized gallery images | https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/instance-specialized-image-version |
141| 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 |
142| 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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