Azure Cloud Services
An Azure platform as a service offer that is used to deploy web and cloud applications.
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@Mohit Kumar Apologies for the delay in response and all the inconvenience caused because of the issue.
Yes VM is multiple Fault Domain can be placed in same Update Domain also , but azure make sure atleast one Update Domain is up and running at any time.
Each virtual machine in your availability set is assigned an update domain and a fault domain by the underlying Azure platform. For a given availability set, five non-user-configurable update domains are assigned by default (Resource Manager deployments can then be increased to provide up to 20 update domains) to indicate groups of virtual machines and underlying physical hardware that can be rebooted at the same time. When more than five virtual machines are configured within a single availability set, the sixth virtual machine is placed into the same update domain as the first virtual machine, the seventh in the same update domain as the second virtual machine, and so on. The order of update domains being rebooted may not proceed sequentially during planned maintenance, but only one update domain is rebooted at a time. A rebooted update domain is given 30 minutes to recover before maintenance is initiated on a different update domain.
You can read more about it here.
For example this FD0 has UD0 only. FD1 can have UD1 or UD2 based upon backend logic and again backend logic we cannot predict but there is a registry for all these , based on which it will do Updates:
Hope it helps!!!
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