Announcing Public Preview of Instance Mix on Virtual Machine Scale Sets

Today, we are excited to announce the ability to specify multiple different VM sizes in Virtual Machine Scale Sets (VMSS) using flexible orchestration mode. Instance Mix. This new feature allows you to specify up to five different VM sizes to use for your VMSS deployment. This not only simplifies the management of your scale sets, but also allows you to optimize your deployments based on price or capacity through allocation strategies.

profit

1. Single API call: You can specify and deploy up to five VM sizes in a scale set with a single API call.
2. Optimized distribution: Using CapacityOptimized to optimize available capacity in an Azure region/zone can give you more confidence that you’ll get the capacity you request. For cost-sensitive customers who still want to leverage capacity signals, the LowestPrice allocation strategy takes both factors into account.
3. Auto allocation: Allocation strategies allow Azure to determine which VMs are most readily available and most cost-effective among a given set of VMs.
4. Easily scalable by combining multiple VM offerings: Spot Priority Mix lets you deploy a mix of VM sizes with Spot and On-Demand pricing across your scale set.
5. Simplified Management: Instead of manually deploying multiple VMs into a scale set, you can now deploy multiple different VM sizes into a scale set.
6. Secure the required capacity: By leveraging a mix of VM sizes, you can leverage a larger capacity pool, increasing your ability to get the capacity you need.

What’s new

VMSS Instance Mix introduces several new properties to the VMSS API, including:

• sku profile: Comprehensive properties for the vmSizes and allocationStrategy lists.
• vm size: A list of VM sizes to deploy.
• Allocation Strategy: The property specifies the allocation strategy. There are currently two options: LowestPrice and CapacityOptimized.
  • Lowest price: When evaluating which VM size split to use, Azure first looks at the least expensive VM size specified, and then looks at the capacity of that VM. It tries to deploy as many of the least expensive VMs as possible before moving on to the next least expensive VM size that has available capacity.
  • Capacity Optimization: Azure only considers available capacity by default when evaluating which VM size split to use, and does not consider price when determining which SKU split to deploy.

The VMSS instance mix call creates a new section in the ARM template.

 "skuProfile": {
      "vmSizes": [
        {
          "name": "Standard_D16s_v4"
        },
        {
          "name": "Standard_E16s_v5"
        },
        {
          "name": "Standard_D16s_v5"
        }
      ],
      "allocationStrategy": "CapacityOptimized" | ”LowestPrice”
    },

Learn more about how Instance Mix works and sign up for a preview. documentation.