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Session host statuses and health checks in Azure Virtual Desktop

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The Azure Virtual Desktop Agent regularly runs health checks on the session host. The agent assigns these health checks various statuses that include descriptions of how to fix common issues. This article tells you what each status means and how to act on them during a health check.

Session host statuses

The following table lists all statuses for session hosts in the Azure portal each potential status. Available is considered the ideal default status. Any other statuses represent potential issues that you need to take care of to ensure the service works properly.

Note

If an issue is listed as non-fatal, the service can still run with the issue active. However, we recommend you resolve the issue as soon as possible to prevent future issues. If an issue is listed as fatal, it prevents the service from running. You must resolve all fatal issues to make sure your users can access the session host.

Session host status Description Load balancing How to resolve related issues
Available This status means that the session host passed all health checks and is available to accept user connections. If a session host has reached its maximum session limit but has passed health checks, it's still listed as “Available." New user sessions are load balanced here. N/A
Needs Assistance The session host didn't pass one or more of the following non-fatal health checks: the Geneva Monitoring Agent health check, the Azure Instance Metadata Service (IMDS) health check, or the URL health check. In this state, users can connect to VMs, but their user experience may degrade. You can find which health checks failed in the Azure portal by going to the Session hosts tab and selecting the name of your session host. New user sessions are load balanced here. Follow the directions in Error: Session hosts are stuck in "Needs Assistance" state to resolve the issue.
Shutdown The session host has been shut down. If the agent enters a shutdown state before connecting to the broker, its status changes to Unavailable. If you've shut down your session host and see an Unavailable status, that means the session host shut down before it could update the status, and doesn't indicate an issue. You should use this status with the VM instance view API to determine the power state of the VM. Not available for load balancing. Turn on the session host.
Unavailable The session host is either turned off or hasn't passed fatal health checks, which prevents user sessions from connecting to this session host. Not available for load balancing. If the session host is off, turn it back on. If the session host didn't pass the domain join check or side-by-side stack listener health checks, refer to the table in Health check for ways to resolve the issue. If the status is still "Unavailable" after following those directions, open a support case.
Upgrade Failed This status means that the Azure Virtual Desktop Agent couldn't update or upgrade. This status doesn't affect new nor existing user sessions. New user sessions are load balanced here. Follow the instructions in the Azure Virtual Desktop Agent troubleshooting article.
Upgrading This status means that the agent upgrade is in progress. This status updates to “Available” once the upgrade is done and the session host can accept connections again. New user sessions are load balanced here. If your session host is stuck in the "Upgrading" state, then reinstall the agent.

Health check

The health check is a test run by the agent on the session host. The following table lists each type of health check and describes what it does.

Health check name Description What happens if the session host doesn't pass the check
Domain joined Verifies that the session host is joined to a domain controller. If this check fails, users won't be able to connect to the session host. To solve this issue, join your session host to a domain.
Geneva Monitoring Agent Verifies that the session host has a healthy monitoring agent by checking if the monitoring agent is installed and running in the expected registry location. If this check fails, it's semi-fatal. There may be successful connections, but they'll contain no logging information. To resolve this issue, make sure a monitoring agent is installed. If it's already installed, contact Microsoft support.
Side-by-side (SxS) Stack Listener Verifies that the side-by-side stack is up and running, listening, and ready to receive connections. If this check fails, it's fatal, and users won't be able to connect to the session host. Try restarting your virtual machine (VM). If restarting doesn't work, contact Microsoft support.
App attach health check Verifies that the MSIX app attach service is working as intended during package staging or destaging. If this check fails, it isn't fatal. However, certain apps stop working for end-users.
Domain trust check Verifies the session host isn't experiencing domain trust issues that could prevent authentication when a user connects to a session. If this check fails, it's fatal. The service won't be able to connect if it can't reach the authentication domain for the session host.
Metadata service check Verifies the metadata service is accessible and returns compute properties. If this check fails, it isn't fatal.

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