Automation runbooks allows you to automatically perform standard remediations in response to VM alerts, like restarting or stopping the VM.
Previously, during VM alert rule creation you were able to specify an Automation webhook to a runbook in order to run the runbook whenever the alert triggered. However, this required you to do the work of creating the runbook, creating the webhook for the runbook, and then copying and pasting the webhook during alert rule creation. With this new release, the process is much easier because you can directly choose a runbook from a list during alert rule creation, and you can choose an Automation account which will run the runbook or easily create an account.
Reference:
https://azure.microsoft.com/en-us/blog/automatically-remediate-azure-vm-alerts-with-automation-runbooks/