How to track the place of a VM, if does not specifc Availability Zone for this VM

Question

How to track the place of a VM, if does not specifc Availability Zone for this VM

Zhiwen Zhou 20 Microsoft Employee

We can create a VM without using Availability Zone(choose the No infrastructure redundancy required option), and I have some confusions about it: 1) Is a VM not specific a zone will be allocate a random zone? 2) If all VM are allocated to the zones, how can I get the zone information of a VM if I don't select a zone when creating it (Can't see any availability information in Azure portal now)?

kobulloc-MSFT 26,811 Reputation points Microsoft Employee Moderator

2024-01-12T17:35:09.3733333+00:00
Hello, @Zhiwen Zhou !

This is a popular question and I need to get some additional sources to confirm this but what I remember is this:

What happens if I don't specify an availability zone when I create my VM?
In this case, the VM will be created somewhere in the Azure Region where they are deployed based on current availability.

How do I get the Availability Zone information of my VM?
Since the VM is being created in whatever Availability Zone is optimal each time it's allocated, there's no set Availability Zone and even when an Availability Zone is set on creation it's a much more complicated process because Availability Zone numbers don't match from subscription to subscription to avoid a mass use of "Availability Zone 1" for all subscriptions.
Zhiwen Zhou 20 Reputation points Microsoft Employee

2024-01-12T17:48:20.1733333+00:00

Thanks for your reply, I konw the logic zone number not equals to the physical zone for each subscription. So for question 1, I still need to know whether a VM will be create in a zone if not set zone value, in other words, whether there is have VM capacity that does not belong to any zone for a region which is support availability zone?
kobulloc-MSFT 26,811 Reputation points Microsoft Employee Moderator

2024-01-12T17:51:22.92+00:00

Hello, @Zhiwen Zhou ! If you do not set an availability zone when the VM is created, then it will have an availability zone of None which you can verify in the portal. This means that the VM will be deployed wherever it is most optimal each time it is allocated. Does that answer your question?
Zhiwen Zhou 20 Reputation points Microsoft Employee

2024-01-12T17:57:53.9033333+00:00

Sorry I still confuse that is the optimal location locate in a availability zone？Or can you answer are all VMs will be allocate to zones in a availability zone supported region？
kobulloc-MSFT 26,811 Reputation points Microsoft Employee Moderator

2024-01-12T18:19:56.0466667+00:00

No worries! Hopefully this will help to clarify: Datacenters are created to meet demand for services like virtual machines. Availability zones are logical groupings (like a datacenter) that provide redundancy and reliability that protects you from a disaster like a flood that might impact a whole datacenter. This means that an availability zone is just as much what it isn't as much as what it is in that availability zone 1 isn't going to be affected by a disaster that would affect availability zone 2.

So when the availability zone is set to None, then Azure picks a VM in a datacenter based on best availability. This datacenter may be separated enough from another datacenter to qualify as an availability zone (and in most regions datacenters do belong to an availability zone).
Mihai Tănăsescu 26 Reputation points

2024-07-15T11:27:02.4266667+00:00

sorry for reviving an older thread....
if Availability zone is set to None and the AZ that Azure picked suddenly goes down, will Azure migrate that VM to a new AZ or will it remain down until the AZ problems are fixed?
kobulloc-MSFT 26,811 Reputation points Microsoft Employee Moderator

2024-07-15T17:22:16.0566667+00:00

Hello, @Mihai Tănăsescu! If the availability zone is set to 1, 2, 3, or none, the result is the same in the case of an outage (if the availability zone goes down): resources in that availability zone will be unavailable until the outage is resolved.

To address this, you can deploy separate copies of your application and data in different availability zones.

Read more:

https://learn.microsoft.com/en-us/azure/reliability/availability-zones-overview

Accepted answer

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kobulloc-MSFT 26,811 Reputation points Microsoft Employee Moderator

2024-01-12T17:35:09.3733333+00:00

Hello, @Zhiwen Zhou !

This is a popular question and I need to get some additional sources to confirm this but what I remember is this:

What happens if I don't specify an availability zone when I create my VM?
In this case, the VM will be created somewhere in the Azure Region where they are deployed based on current availability.

How do I get the Availability Zone information of my VM?
Since the VM is being created in whatever Availability Zone is optimal each time it's allocated, there's no set Availability Zone and even when an Availability Zone is set on creation it's a much more complicated process because Availability Zone numbers don't match from subscription to subscription to avoid a mass use of "Availability Zone 1" for all subscriptions.
Zhiwen Zhou 20 Reputation points Microsoft Employee

2024-01-12T17:48:20.1733333+00:00

Thanks for your reply, I konw the logic zone number not equals to the physical zone for each subscription. So for question 1, I still need to know whether a VM will be create in a zone if not set zone value, in other words, whether there is have VM capacity that does not belong to any zone for a region which is support availability zone?
kobulloc-MSFT 26,811 Reputation points Microsoft Employee Moderator

2024-01-12T17:51:22.92+00:00

Hello, @Zhiwen Zhou ! If you do not set an availability zone when the VM is created, then it will have an availability zone of None which you can verify in the portal. This means that the VM will be deployed wherever it is most optimal each time it is allocated. Does that answer your question?
Zhiwen Zhou 20 Reputation points Microsoft Employee

2024-01-12T17:57:53.9033333+00:00

Sorry I still confuse that is the optimal location locate in a availability zone？Or can you answer are all VMs will be allocate to zones in a availability zone supported region？
kobulloc-MSFT 26,811 Reputation points Microsoft Employee Moderator

2024-01-12T18:19:56.0466667+00:00

No worries! Hopefully this will help to clarify: Datacenters are created to meet demand for services like virtual machines. Availability zones are logical groupings (like a datacenter) that provide redundancy and reliability that protects you from a disaster like a flood that might impact a whole datacenter. This means that an availability zone is just as much what it isn't as much as what it is in that availability zone 1 isn't going to be affected by a disaster that would affect availability zone 2.

So when the availability zone is set to None, then Azure picks a VM in a datacenter based on best availability. This datacenter may be separated enough from another datacenter to qualify as an availability zone (and in most regions datacenters do belong to an availability zone).
Mihai Tănăsescu 26 Reputation points

2024-07-15T11:27:02.4266667+00:00

sorry for reviving an older thread....
if Availability zone is set to None and the AZ that Azure picked suddenly goes down, will Azure migrate that VM to a new AZ or will it remain down until the AZ problems are fixed?
kobulloc-MSFT 26,811 Reputation points Microsoft Employee Moderator

2024-07-15T17:22:16.0566667+00:00

Hello, @Mihai Tănăsescu! If the availability zone is set to 1, 2, 3, or none, the result is the same in the case of an outage (if the availability zone goes down): resources in that availability zone will be unavailable until the outage is resolved.

To address this, you can deploy separate copies of your application and data in different availability zones.

Read more:

https://learn.microsoft.com/en-us/azure/reliability/availability-zones-overview

Answer 1

Hello, @Zhiwen Zhou !

What happens if I create a VM without selecting an availability zone?

If you create a VM without selecting an availability zone, then the VM's availability zone will be set to None . This means that Azure will select the best available location for the VM within in the region that it was deployed each time that it is allocated.

Original screenshot from Andreas Baumgarten:

User's image

So is the VM in an availability zone?

Most likely, yes. There is a high chance that the datacenter the VM is deployed to is part of an availability zone. This doesn't have any significant meaning though unless you are deploying multiple VMs where the goal is to make sure that redundant resources aren't simultaneously affected by availability zone level disasters like a flood. If that is your goal, then you will want to deploy your VMs with high availability.

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How to track the place of a VM, if does not specifc Availability Zone for this VM

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