Scheduled maintenance for Azure VMs

Question

Dear support, we received a notification regarding scheduled maintenance for Azure Virtual Machines in set of regions.

Currently our workloads live in the mentioned regions. We have several AKS clusters based on node pools built on Virtual Machine Scale Sets of DCasv5 SKUs.

Does the mentioned scheduled maintenance affect our AKS node?

Answer 1

Hi @Aliaksandr Matskevich,

Welcome to the Microsoft Q&A Platform! Thank you for asking your question here.

Azure periodically performs updates to improve the reliability, performance, and security of the host infrastructure for virtual machines. Updates are changes like patching the hosting environment or upgrading and decommissioning hardware. A majority of these updates are completed without any impact to the hosted virtual machines. However, there are cases where updates do have an impact:

• If the maintenance doesn't require a reboot, Azure pauses the VM for few seconds while the host is updated. These types of maintenance operations are applied fault domain by fault domain. Progress is stopped if any warning health signals are received.
• If maintenance requires a reboot, you get a notice of when the maintenance is planned. You're given a time window of about 35 days where you can start the maintenance yourself, when it works for you.

Your application may experience a brief service interruption, typically in the form of a short pause or restart, as the system updates the underlying infrastructure. Most maintenance operations are designed to minimize downtime, with advance notifications provided so you can plan accordingly.

Maintenance on a VM generally results in a brief pause or reboot, aiming to keep application downtime to a minimum.

In certain situations, your VM might be automatically migrated to a different physical host during maintenance, ensuring that your application remains unaffected. However, brief performance degradation may occur during the update process.

During the update, your application may temporarily become unresponsive, and users could experience brief connection drops or errors. In some instances, your VM may automatically restart once the maintenance is completed.

If you have any further queries, do let us know.