An Azure service that is used to provision Windows and Linux virtual machines.
If automatic VM guest patching is enabled on a VM, then the available Critical and Security patches are downloaded and applied automatically on the VM. This process kicks off automatically every month when new patches are released. Patch assessment and installation are automatic, and the process includes rebooting the VM as required.
Patches are applied during off-peak hours in the VM's time zone.
refer- https://learn.microsoft.com/en-us/azure/virtual-machines/automatic-vm-guest-patching
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