Check Alive Function

## Background

Reserve Application function is commonly used for large-scale applications, which typically consume a lot of resources and start up slowly. Running the application for a long time may cause server resources to be exhausted or high GPU temperature, which can lead to the application freezing abnormally.

Under this circumstance, the application process may not fully exit, the rendering service cannot perceive the abnormal state of the application. To solve this problem, a Check Alive function under Reserve Application has been introduced. Once the application freezes, the rendering server will automatically restart the application.

## Prerequisite

- LarkXR has been upgraded to version V3.3.4.2.
- The target application must be integrated with the data channel and periodically send messages to it (The message content is not limited, e.g.: "heartbeat").

## Procedure

### Step 1: Enable Check Alive Function

- Log in to the management console and go to the Reserve Application page
- In the configuration of "Reserve Set", select "Yes" for the "Check Alive" (the option is by default "No"), and further configure the "Check Alive Time" (in seconds)
- If the application requires long startup time, extend the detection interval accordingly to avoid the application being mistakenly judged as frozen and restarted during startup.
- Note: The detection interval should be adjusted according to the actual startup time and runtime characteristics of the application.

![Check Alive Function Position](/media/202512/7f3cd66261f848369978e4e3a3a32fce3336.jpeg)

### Step 2: Integrate with Data Channel

Refer to the user manual https://docs.paraverse.cc/doc/1197/

- Ensure the application sends keep alive message(s) to the data channel withing the time interval configured in "Check Alive Time" in Step 1.
- Important: If the application does not send a message within the configured interval, the rendering server will determine the application as "hang" state and will restart it proactively. Hence, be sure the application can send messages on time to avoid unnecessary restarts.