Hello Abhishek Kumar Jha
Welcome to Microsoft Q&A Platform, thanks for posting your query here.
Adding a data disk to the VM should not affect the Azure VM agent status. It's possible that there might be a conflict or compatibility issue between the VM agent and the newly added data disk.
Try to detach the data disk, you can try detaching it temporarily and check if the VM agent status returns to "ready."
If detaching the data disk resolves the issue, it's likely that there is a configuration problem with the disk.
Review the VM's system and application logs to check for any disk-related errors or warnings.
Ensure that the VM agent on the virtual machine is up to date.
Also, if the Azure VM agent status is not ready and the only issue you can see is that python2 is not installed under diagnostic settings, the VM agent relies on Python 2 for certain functionalities. Ensure that Python 2 is installed on your virtual machine.
Double-check the diagnostic settings for your VM. Ensure that the correct versions of Python are specified in the diagnostic settings. Verify that the correct extension is installed and properly configured to use Python 2.
Restart the VM and see if that helps resolve the issue.
Hope this helps.