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--- title: Feature Analysis Cloud Services vs Virtual Machine Scale Sets description: Learn about the feature set available in Cloud Services and Virtual Machine Scale Sets ms.topic: concept-article ms.service: azure-cloud-services-classic author: surbhijain ms.author: surbhijain ms.reviewer: mimckitt ms.date: 07/24/2024 ms.update-cycle: 1095-days ms.custom: cloud-services-extended-support # Customer intent: As a cloud solution architect, I want to compare the features of Cloud Services and Virtual Machine Scale Sets, so that I can select the best deployment model for my organization's scalability, availability, and management needs. --- # Feature Analysis: Cloud Services (extended support) and Virtual Machine Scale Sets > [!IMPORTANT] > As of March 31, 2025, cloud Services (extended support) is deprecated and will be fully retired on March 31, 2027. [Learn more](https://aka.ms/csesretirement) about this deprecation and [how to migrate](https://aka.ms/cses-retirement-march-2025). 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](/azure/virtual-machine-scale-sets/overview) ## 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](https://azure.microsoft.com/support/legal/sla/cloud-services/v1_5/)|[SLA](https://azure.microsoft.com/support/legal/sla/virtual-machine-scale-sets/v1_1/)|[SLA](https://azure.microsoft.com/support/legal/sla/virtual-machine-scale-sets/v1_1/)| |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](deploy-prerequisite.md) for Cloud Services (extended support). - View [frequently asked questions](faq.yml) for Cloud Services (extended support).