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 performed without any impact to the hosted virtual machines. However, there are cases where updates do have an impact.
How do I know maintenance is happening?
What can I do to minimize downtime?
Links
https://docs.microsoft.com/en-us/azure/virtual-machines/windows/maintenance-notifications
https://docs.microsoft.com/en-us/azure/virtual-machines/windows/maintenance-and-updates
https://docs.microsoft.com/en-us/azure/virtual-machines/windows/scheduled-events