Azure Site recovery unsupported ubuntu kernel

Question

Hello, as the title says I get an error when trying to replicate a Azure Ubuntu 20.4 VM to another availability zone.

"This version of mobility service doesn't support the operating system kernel version (5.11.0-1021-azure) running on the source machine."

When is this kernel version supported on Azure? Will it take long or do I have to downgrade the kernel?

Thanks in advance

Answer 1

Hello @keloken

There are prerequisites for disaster recovery of Azure VMs, using the Azure Site Recovery service.

Here is kernel Support matrix - https://learn.microsoft.com/en-us/azure/site-recovery/azure-to-azure-support-matrix#supported-ubuntu-kernel-versions-for-azure-virtual-machines

You may try to downgrade kernel. Here is an example for Ubuntu 20.04
Identify actual kernel with command:
sudo uname -a

Linux test 5.11.0-1021-azure #22~20.04.1-Ubuntu SMP Fri Oct 29 01:11:25 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

First step is to identify the necessary packages that you need to install. This is done by executing the following command.
sudo apt search linux-azure | grep 5.4.0-1062

Afterwards you know which package needs to be installed.
sudo apt install linux-image-5.4.0-1062-azure

In the next step the actual kernel gets removed.
sudo apt remove linux-image-5.11.0-1021-azure

During the process you confirm with <No> that you do not want to abort the removal process.

Kernel removal confirmation window

As the last step you initiate a reboot with sudo reboot

The welcome screen should now state the target kernel version.
Check the kernel version
sudo uname -a
Linux test 5.4.0-1062-azure #65-Ubuntu SMP Sun Oct 10 02:30:34 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

https://www.danielstechblog.io/downgrade-the-linux-kernel-on-an-azure-ubuntu-vm/

Answer 2

This issue is still not fixed, i.e. the kernel that comes with Ubuntu 20.04 is still not supported with the mobility agent for site recovery.