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?
- In the Azure portal you can add the "Maintenance" column
- Scheduled maintenance is reported to Azure Activity Logs so you can create a Health Alert based on that
What can I do to minimize downtime?
- If the host does not require a reboot, Azure will pause your VM, patch the host, and then resume the VM
- If the host does require a reboot, you will, typically, get notice 35 days in advance
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