To monitor load balancing health on Horizon Connection Server, follow these best practices.
To avoid flooding Connection Server with a large number of health check requests, set the polling interval to 30 seconds, with a timeout of two or three times that period. Try to have no more than two load balancers sending probes to one Connection Server instance.
The only supported health check is a fetch of favicon.ico. To minimize the cost of the probe, use the HEAD method where possible. Whether or not the check is successful, you must drop the connection after the fetch by either adding a Connection: close header to the request or else using an HTTP/1.0 request.
An example of using the HEAD method in the send string of the load balancer:
HEAD /favicon.ico HTTP/1.1\r\nHost: \r\nConnection: Close\r\n
The HTTP status is typically 200. If the Connection Server is administratively disabled, the status will return as 503. See Disable or Enable Horizon Connection Server in Horizon Console for details.
Response codes
| HTTP Status | Description |
|---|---|
| 200 OK | The Connection Server is healthy and responsive to brokering requests. |
| 304 Not Modified | As 200, but the favicon file is unchanged and is not being served. This is in response to a GET or HEAD request with an If-None-Match header. |
| 500 Internal Server Error | The favicon file cannot be served, either because it is not accessible or there is a critical error. The Connection Server is not healthy. |
| 502 Bad Gateway | A subsystem is reporting a problem. The Connection Server is not healthy. |
| 503 Service Unavailable | The Connection Server has been administratively disabled and will not accept brokering requests. |
| 504 Gateway Timeout | The brokering subsystem is not responsive, due to service shutdown or resource exhaustion. The Connection Server is not healthy. |
For timeout settings and load balancer persistence values, see the KB article on Timeout Settings and Load Balancer Persistence.
Additional Configuration Options
A new property can be configured in the locked.properties file to control how frequently the Secure Gateway updates its cached favicon health check result:
faviconHealthCheckIntervalSeconds=30
By default, the favicon health check result will be refreshed every 60 seconds. This cache helps the Connection Server run less by serving load balancer health check requests. This limits the number of direct requests and the use of Tomcat threads.
Administrators can set the refresh interval to meet specific monitoring requirements. A shorter interval (such as 15 seconds) ensures more frequent status updates, whereas a longer interval (up to 60 seconds) conserves server resources. It is advisable to maintain the interval within the range of 15 to 60 seconds, with 60 seconds being considered the optimal practice.
Custom Health Check Options
Starting with the 2512 release, administrators can configure a custom health check endpoint served directly through the Secure Gateway. This provides more flexibility for monitoring Connection Server health.
A new custroot\health directory is available under:
C:\Program Files\Omnissa\Horizon\Server\sslgateway\conf\custroot\health
Note: The path shown assumes the default Connection Server installation directory (C:\Program Files). If the Horizon Connection Server is installed in a different location, adjust the path accordingly.
Static content placed under this directory can be used to host lightweight health check pages or status probes, which are then served from https://<server-address>/customer/health/.
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If the Connection Server is administratively disabled, the files are still served (HTTP 200).
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If the broker is unhealthy (
502 Bad Gateway,504 Gateway Timeout, or similar error), the files will not be served.
Only safe, static file types are supported, including:
-
image/jpeg,image/gif,image/png,image/x-icon -
text/html,text/css -
ico
This enhancement allows for the implementation of custom monitoring and health endpoints while maintaining the security and stability of the Connection Server.
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