Migrating a CentOS Virtual Appliance to Azure

I had an interesting ask to migrate an on premise virtual appliance to Azure. I thought this would be straight forward, but here I am writing why this situation wasn’t, lol.

This particular operating system was CentOS 7. The vendor said it is supported to migrate to Azure and I found that Microsoft has documentation on how to prep a VM for Azure here. I followed all the steps except deprovisioning as I was migrating a single VM. Once I shutdown the VM, I used PowerShell to upload the vhd. I recommend using PowerShell since it handles making sure the virtual size of the vhd is aligned to 1 MiB. Azure Storage Explorer does not do this, fyi.

connect-azaccount -Environment azureusgovernment
select-azsubscription <sub>
$resourceGroup = 'rg-<project>'
new-azresourcegroup $resourceGroup -location 'usgovvirginia'
$path = 'C:\Temp\export\va\Virtual Hard Disks\va.vhd'
$location = 'usgovvirginia'
$name = 'va-os-disk'
Add-AzVhd -LocalFilePath $path -ResourceGroupName $resourceGroup -Location $location -DiskName $name -OsType Linux -Verbose 

After running the above command, the disk will be uploaded and you can create a new VM off of it. Once I did all of that, I tried to SSH into the VM and it was rejecting my credentials. I was confused, so I restored the VM into Hyper-V and I had the same issue.

Knowing it is a SSH issue, I looked at the sshd_config file and noticed PasswordAuth was set to no. The appliance had this set to Yes, so something changed it during VM prep.

After some trial and error, I narrowed it down to this part:

Now that I know what step it is happening, I accessed the terminal instead of using my ssh client to change passwordAuthentication back to yes which fixed it. Re-uploaded and I was able to SSH into the VM. But wait, that’s not all.

The Linux agent was not in a ready state. I cat /var/log/waagent.log and saw Waiting for cloud-init to copy ovf-env.xml to /var/lib/waagent/ovf-env.xml

That file did not exist in /var/lib/waagent and was lost why it wasn’t there. After reading a couple open GitHub issues about this, I found a post https://thomasthornton.cloud/2020/04/16/cloud-init-does-not-appear-to-be-running-error-after-installing-walinuxagent/ that had the same issue I had. The fix is just to manually create the ovf-env.xml file and edit the username and hostname. I did exactly that, restarted the waagent service and everything automagically started working.

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