Azure update management center onetime update vs Guest patching with update management center

Question

I want to know the difference , in update management center there are two options-

1 - "one time update "

2- When we opt for scheduling with Maintenance Configuration it will show "Guest patching with update management center"

Is there any difference in both the way update management center apply patch on OS ? like in first method there is no need to add any extension on vms, it will be taken care by Update management center . will it be same for second case also (Guest patching with update management center) .

or anything is required in second case. because we are planning to patch bulk VMs so we are trying to understand opting for scheduling .

--- is there any option we can integrate any script before the update management center apply the patches on VM? in update management using automation account, there are option available to add pre and post script.

Answer 1

@Azuretech Thank you for this question. Please find below the response to your questions related to update management center:

1. The difference between the methods available for update installation (scheduled or onetime) is based on the schedule of updates - they are both done by the "update management center" extension. This extension is automatically installed when you initiate any update management center operations such as check for updates, install one time update, periodic assessment on your machine and there is no manual intervention required for managing/installing this extension. Please see the details in this link (especially the description after the image). For managing updates on multiple machines, please see this link.
2. Update management center (preview version as available now) does not support pre/post installation script as of now.

Please let me know if you have any question.