question

ManivelRajarathinam-9286 avatar image
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ManivelRajarathinam-9286 asked ·

Azure DR Query

Hi Team,

We have 2 sites.
UK South -->Protected site-->It has a dedicated AD/DNS server in the forest called"contoso.com"
UK West --->DR Site--->It has a dedicated AD/DNS server in the same forest called"contoso.com"

VPN is there between 2 sites.

1)UK South --> 3 VMs are there
app01,app02 & app03.All these 3 VMs are tagged to EUS-VNET01
These 3 VMs are having static public IP.
Subnet range is 10.100.25.0/24

APP01-->10.100.25.10
APP02-->10.100.25.11
APP03-->10.100.25.12

2)UK West ---> DR Site.

Customer request.

After doing failover(app02 only) from UK south to UK West,the app02 should be turned on and it should come in to network also public ip should be the same

I failed over from UK SOUTH to UK WEST and the VM has turned on but it does not have NETWORK connectivity.I could not reach via web/rdp.

"This the default design ?.,Azure protected & recovery site cannot act
as an Active/Active model.When perform the DR drill,all the protected sites virtual machines should be part of DR drill then only the recovery site VMs will continue to run without any connectivity issue.
We cannot run app1 in UK South and another app2 in UK WEST with the same subnet/same IP."


?

Can someone give some inputs?

Thank you,
Raj






azure-site-recovery
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1 Answer

SadiqhAhmed-MSFT avatar image
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SadiqhAhmed-MSFT answered ·

@ManivelRajarathinam-9286 Thank you for your post and I apologize for the delayed response!

Public IP is regionally based. You can’t have the same public IP in a different region.
For the private IPs, when you are in the portal, you have the option to modify the target Vnet associated, also you can use Network mapping: https://docs.microsoft.com/en-us/azure/site-recovery/azure-to-azure-network-mapping

Regarding the problem that you can’t log in, this is not the expected behavior. Validate if there is a RDP rule missing in the subnet / vnic NSGs.

About Active Active model this is not what ASR was designed for.
For this kind of solution for web apps, you should work with Load Balancer, such as Azure Front Door, Traffic Manager, or Azure Load Balancer.


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Thanks Sadigh.

I have one final doubt.Please help if you have any idea.

Example.

APP1 VM is located on protected site.
Configured static IP from Azure portal also enabled static IP address in guest OS(TCP/IP settings IPv4).

Post failover,I noticed these.
I see,the same static IP address from DR site which is good.
From guest OS,the same IP address is providing via DHCP not static.

Is this default behavior?

Thanks,
Raj

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SadiqhAhmed-MSFT avatar image SadiqhAhmed-MSFT ManivelRajarathinam-9286 ·

@ManivelRajarathinam-9286 This is expected behavior.
When a VM is failed over, we create a new VM in target region and a new NIC is attached with platform level properties assigned to the NIC object in Azure.
Any time in Azure when you Attach a NIC to a VM it will use DHCP by default within the OS.
ASR will not make any OS level changes to the NIC properties.


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