Since there is no default way of monitoring the unavailable Session hosts. Follow the simple steps below to monitor and alert on the health status of the WVD Session hosts.
You need to enable WVD Diagnostics to create this alert. If you have not configured yet please refer this link
Verifying the logs in log analytics workspace
WVDAgentHealthStatus | where EndpointState contains “Unhealthy”This displays the logs of unhealthy Session hosts
Click on “New Alert Rule”
Specify the Rule name and action group to send notification to.
You should get a notification as below, Whenever the session host health goes to unhealthy state. This is a workaround to monitor the unavailability of the session hosts.