How to boot a AWS Elastic Disaster Recovery Failback client on Azure VM.

Question

Hello everyone out there! 

 

I am trying to setup the AWS Elastic Disaster Recovery for the production hosted on Azure Cloud.

I have created the VPN Connection between Azure and AWS VPCs and installed the AWS Replication Agent on every source instance/VM. 

 

The replication agent done it's job and completed the replication of Azure VMs to AWS. After replication the drill was successfully performed and created a recovery instance in AWS Elastic Disaster Recovery Console to perform the failback to original server or we can failback to another server which have same or more configurations than source server.

 

Now, AWS provide the failback agent in .iso format which is a live Linux image that acts as a connector to replicate the data from AWS to Destination Server.  But Azure doesn't support .iso to boot any VM as it uses .vhd or .vhdx as supported disc types.

 

I have tried creating VHD using various convertors (V2V Convertor, ISOBuster 2.0 etc,) and Hyper-V by creating a blank VHD and then mounted that ISO on Hyper-V VM.

But the problem is that it is a live image that will act only as a connector and credentials verification to check the replication server on AWS, and we can not install it as a OS. 

 

I want to use this image as bootable VHD that can provision an Azure VM and perform failback on that Virtual Machine.

Please help me in this event. 

 

Regards,

Rahul Somra

Answer 1

It would be really helpful if someone can give the solution to boot the cloud VM from that live .iso or can manually install the GRUB and Kernel on the disc.

Answer 2

Hi, @Rahul Somra

I don't think this restriction can be circumvented.

AWS DRS defines a fallback client boot mode.
On the other hand, Azure cannot boot from ISO.

You need to create his VHD volume from the ISO using local Hyper-V etc. and upload it back to Azure as described in the following article.
https://stackoverflow.com/questions/45217911/is-it-possible-to-boot-an-azure-vm-with-a-different-bootable-iso

Answer 3

Hi @Rahul Somra ,

Good night!

Like you, I have been trying to test the same process. I found the following article: Building a disaster recovery site on AWS for workloads on Microsoft Azure (https://aws.amazon.com/pt/blogs/storage/building-a-disaster-recovery-site-on-aws-for-workloads-on-microsoft-azure/#:~:text=Configure%20AWS%20DRS%20on%20Azure,back%20from%20AWS%20to%20Azure.

)

Look at the section "3.1. Prepare Failback Client", where the author is proposing a method to generate a bootable disk using the iso image as source. He created a script that aims to create the bootable disk in: https://github.com/aws-samples/aws-drs-failback-client-azure-gcp

I followed the procedure using VM Workstation and found a problem with it. The script will fail due to lack of space in the "/root" folder to perform the activities. After that, I used Hyper-V to execute the script adjusting it to download the iso image and perform the activities in a "disk 1" with enough space and setting up a separate disk "disk 2" as target for the bootable disk creation.

I was able to complete the script "successfully" and then follow these steps:

1) Converting VHDX to VHD (Powershell with Administrator Mode)

Convert-VHD -Path "<name_source>.vhd" -DestinationPath "<name_target>.vhd" -VHDType Fixed

2)Upload the VHD file to an Azure Blob:

.\azcopy.exe cp "<name_target>.vhd" "<accessSas for blob>"

3)Create a managed disk in Azure based on the VHD file:

az disk create -g <resource group> -n <disk name> -l <region> --os-type Linux --sku standard_lrs --hyper-v-generation V1 --source <blob URL>

4)Create a VM using this disk as source

Unfortunately, after the VM creation, it didn't boot properly in Azure. I tried to boot also in Hyper-V using the VHD created by the script and it didn´t work.

You may be able to troubleshoot the problem and if so please share your advances.

Best Regards, Luis