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Important
As of March 31, 2025, cloud Services (extended support) is deprecated and will be fully retired on March 31, 2027. Learn more about this deprecation and how to migrate.
This article provides a feature analysis of Cloud Services (extended support) and Virtual Machine Scale Sets. For more information on Virtual Machine Scale Sets, visit the documentation here
Basic setup
| Feature | CSES | Virtual Machine Scale Sets (Flex) | Virtual Machine Scale Sets (Uniform) |
|---|---|---|---|
| Virtual machine type | Basic Azure PaaS VM (Microsoft.compute/cloudServices) | Standard Azure IaaS VM (Microsoft.compute/virtualmachines) | Scale Set specific VMs (Microsoft.compute /virtualmachinescalesets/virtualmachines) |
| Maximum Instance Count (with FD guarantees) | 1100 subject to capacity and load balancer support | 1000 | 3000 (1000 per Availability Zone) |
| SKUs supported | D, Dv2, Dv3, Dav4 series, Ev3, Eav4 series, G series, H series | D series, E series, F series, A series, B series, Intel, AMD; Specialty SKUs (G, H, L, M, N) aren't supported | All SKUs |
| Full control over VM, NICs, Disks | Limited control over NICs and VM via CS-ES APIs. No support for Disks | Yes | Limited control with virtual machine scale sets VM API |
| RBAC Permissions Required | Compute Virtual Machine Scale Sets Write, Compute VM Write, Network | Compute Virtual Machine Scale Sets Write, Compute VM Write, Network | Compute Virtual Machine Scale Sets Write |
| Accelerated networking | No | Yes | Yes |
| Spot instances and pricing | No | Yes, you can have both Spot and Regular priority instances | Yes, instances must either be all Spot or all Regular |
| Mix operating systems | Limited Windows support | Yes, Linux and Windows can reside in the same Flexible scale set | No, instances are the same operating system |
| Disk Types | No Disk Support | Managed disks only, all storage types | Managed and unmanaged disks, All Storage Types |
| Disk Server Side Encryption with Customer Managed Keys | No | Yes | |
| Write Accelerator | No | No | Yes |
| Proximity Placement Groups | No | Yes, read Proximity Placement Groups documentation | Yes |
| Azure Dedicated Hosts | No | No | Yes |
| Managed Identity | No | User Assigned Identity Only | System Assigned or User Assigned |
| Azure Instance Metadata Service | No | Yes | Yes |
| Add/remove existing VM to the group | No | No | No |
| Service Fabric | No | No | Yes |
| Azure Kubernetes Service (AKS) / AKE | No | No | Yes |
| UserData | No | Yes | Yes |
Autoscaling and instance orchestration
| Feature | Cloud Services (extended Support) | Virtual Machine Scale Sets (Flex) | Virtual Machine Scale Sets (Uniform) |
|---|---|---|---|
| List VMs in Set | No | Yes | Yes |
| Automatic Scaling (manual, metrics based, schedule based) | Yes | Yes | Yes |
| Auto-Remove NICs and Disks when deleting VM instances | Yes | Yes | Yes |
| Upgrade Policy (VM scale sets) | AutoUD and ManualUD policies. No support for Rolling. Cloud Services - Create Or Update - REST API (Azure Compute) | No, upgrade policy must be null or [] during create | Automatic, Rolling, Manual |
| Automatic OS Updates | Yes | No | Yes |
| Customer Defined OS Images | No | Yes | Yes |
| In Guest Security Patching | No | Yes | No |
| Terminate Notifications (VM scale sets) | No | Yes, read Terminate Notifications documentation | Yes |
| Monitor Application Health | No | Application health extension | Application health extension or Azure Load balancer probe |
| Instance Repair (VM scale sets) | No | Yes, read Instance Repair documentation | Yes |
| Instance Protection | No | No, use Azure resource lock | Yes |
| Scale In Policy | No | No | Yes |
| Get Instance View | Yes | No | Yes |
| VM Batch Operations (Start all, Stop all, delete subset, etc.) | Yes | Partial, Batch delete is supported. Other operations can be triggered on each instance using VM API) | Yes |
High availability
| Feature | Cloud Services (extended Support) | Virtual Machine Scale Sets (Flex) | Virtual Machine Scale Sets (Uniform) |
|---|---|---|---|
| Availability SLA | SLA | SLA | SLA |
| Availability Zones | No | Specify instances land across 1, 2, or 3 availability zones | Specify instances land across 1, 2, or 3 availability zones |
| Assign VM to a Specific Availability Zone | No | Yes | No |
| Fault Domain – Max Spreading (Azure maximally spreads instances) | Yes | Yes | Yes |
| Fault Domain – Fixed Spreading | Five update domains | 2-3 FDs (depending on regional maximum FD Count); 1 for zonal deployments | 2, 3 5 FDs 1, 5 for zonal deployments |
| Assign VM to a Specific Fault Domain | No | Yes | No |
| Update Domains | Yes | Depreciated (platform maintenance performed FD by FD) | Five update domains |
| Perform Maintenance | No | Trigger maintenance on each instance using VM API | Yes |
| VM Deallocation | No | Yes | Yes |
Networking
| Feature | Cloud Services (extended Support) | Virtual Machine Scale Sets (Flex) | Virtual Machine Scale Sets (Uniform) |
|---|---|---|---|
| Default outbound connectivity | Yes | No, must have explicit outbound connectivity | Yes |
| Azure Load Balancer Standard SKU | No | Yes | Yes |
| Application Gateway | No | Yes | Yes |
| Infiniband Networking | No | No | Yes, single placement group only |
| Azure Load Balancer Basic SKU | Yes | No | Yes |
| Network Port Forwarding | Yes (NAT Pool for role instance input endpoints) | Yes (NAT Rules for individual instances) | Yes (NAT Pool) |
| Microsoft Edge Sites | No | Yes | Yes |
| Ipv6 Support | No | Yes | Yes |
| Internal Load Balancer | No | Yes | Yes |
Backup and recovery
| Feature | Cloud Services (extended Support) | Virtual Machine Scale Sets (Flex) | Virtual Machine Scale Sets (Uniform) |
|---|---|---|---|
| Azure Backup | No | Yes | No |
| Azure Site Recovery | No | Yes (via PowerShell) | No |
| Azure Alerts | Yes | Yes | Yes |
| VM Insights | No | Can be installed into individual VMs | Yes |
Next steps
- View the deployment prerequisites for Cloud Services (extended support).
- View frequently asked questions for Cloud Services (extended support).