Public Preview: Upgrade Policies for Virtual Machine Scale Sets with Flexible Orchestration

The upgrade policy of a Virtual Machine Scale Set determines how virtual machines can be brought up to date with the latest scale set model. Before today, upgrade policies were available for Virtual Machine Scale Sets with Uniform Orchestration. Now the same upgrade policies available for Uniform Orchestration are available for Virtual Machine Scale Sets with Flexible Orchestration.

The upgrade policies available for Virtual Machine Scale Sets are Automatic, Manual and Rolling. Additionally, if using a Rolling upgrade policy, you can choose to enable MaxSurge to create new instances with the updated scale set model to replace virtual machines using the old model.

Automatic upgrade policy

With an automatic upgrade policy, the scale set makes no guarantees about the order of virtual machines being brought down. The scale set might take down all virtual machines at the same time to perform upgrades.

Automatic upgrade policy is best suited for DevTest scenarios where you aren't concerned about the uptime of your instances while making changes to configurations and settings.

Manual upgrade policy

With a manual upgrade policy, you choose when to update the scale set instances. Nothing happens automatically to the existing virtual machines when changes occur to the scale set model. New instances added to the scale set use the most update-to-date model available.

Manual upgrade policy is best suited for workloads where you require more control over when and how instances are updated.

Rolling upgrade policy + MaxSurge  

With a rolling upgrade policy, the scale set performs updates in batches. You also get more control over the upgrades with settings like batch size, max healthy percentage, prioritizing unhealthy instances and enabling upgrades across availability zones. Additionally, you can enable MaxSurge which will create new virtual machines to replace virtual machines running in the old model. Using MaxSurge ensures your scale set does not see any reduced capacity during an upgrade. 

Rolling upgrade policy is best suited for production workloads that require a set number of instances always be available. Rolling upgrades is the safest way to upgrade instances to the latest model without compromising availability and uptime.

Try the upgrade policies for Virtual Machine Scale sets today.