Azure-docs: wrong subnetmask parameter in the PowerShell Script?

[omnimose]

Why the subnet mask parameter is 255.255.255.255?
"SubnetMask"="255.255.255.255";

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Document Details

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• ID: 09504e18-c72f-07ee-3ef8-dc9ed44562ca
• Version Independent ID: 8058bb4f-2321-ddf2-9930-0cc767b68a62
• Content: Create a SQL Server availability group listener in Azure virtual machines
• Content Source: articles/virtual-machines/windows/sql/virtual-machines-windows-portal-sql-alwayson-int-listener.md
• Service: virtual-machines-sql
• GitHub Login: @MikeRayMSFT
• Microsoft Alias: mikeray

[Karishma-Tiwari-MSFT]

Thanks for the feedback! We are currently investigating and will update you shortly.

[Karishma-Tiwari-MSFT]

@MikeRayMSFT It looks like a sample value to me. Can you please help clarify on this one and do we need to make any doc changes for this? Please let me know. Thanks :)

[Karishma-Tiwari-MSFT]

@MikeRayMSFT Did you get a chance to take a look at this one? Thanks.

[Karishma-Tiwari-MSFT]

@MikeRayMSFT @cynthn Any suggestions on this? Let me know and I can edit the doc. Thanks.

[MikeRayMSFT]

@Karishma-Tiwari-MSFT thanks for your patience. Checking into it now. I've reached out to some PG resources to verify the requirement. As I recall, the subnet value isn't used in the cluster parameter, but it's required for the script to run.

[MashaMSFT]

Hi @omnimose, thank you for patience as we continue looking into this, and I apologize for the delay. I'm still investigating this.

Would you mind clarifying your question? Do you think the subnet mask should be something different? Or should the subnet mask not be included at all?

Thanks!
Masha from the SQL Docs team

[MashaMSFT]

Hi @omninose, I wanted to follow up once more and check on this. Would you mind providing some clarity around your request? Unfortunately, if we do not hear back from you, we'll have to close out this Git Issue :(

Thanks!
Masha from the SQL Docs team

[omnimose]

@MashaMSFT Although I am not sure, to me subnet mask seems not right. Anybody could explain why we need this step here? and why we need to set the subnet mask to 255.255.255.255?

[MashaMSFT]

Hi @omnimose , thanks again for reaching out, and my apologies for the delay in response. Typically when IP address is set, a subnet mask is assigned so that a VM can resolve network ID and host ID portions of an IP address. IP address and subnet mask go hand in hand and setting it to 255.255.255.255 in Always on doc is essentially forcing one to one mapping of load balancer IP with cluster IP.

The cluster subnet mask is 255.255.255.255, and the listener probe subnet mask must match that of the cluster subnet mask.

I hope that helps and please let me know if we can be of further assistance? If not, we will proceed with closing out this Git Issue in a few business days.

Thanks!
Masha from the SQL Docs team

[daveberm]

I always use 255.255.255.255 without a problem. My understanding is that by using that subnet you avoid an IP address conflict with the ILB, which shares the same IP address. /32 is creates a host specific route, so the node never tries to resolve that IP beyond itself. I've never tried to us it without that subnet mask so I can't confirm whether you will have issues or not. nut can confirm 255.255.255.255 works fine.

[MashaMSFT]

Hi @omnimose , it's been some time since we've heard from you, so we will assume that your question has been answered and proceed with closing out this Git Issue. Please feel free to comment should you need anything further.

Thanks!
Masha from the SQL Docs team

please-close

[fivefq]

I guess @davebern made a point. Because I always ran into IP conflict issue while bringing up the role when the same IP address is configured in the load balancer and listener.