Whenever you start the Kernel and WebRunner on Linux OS, a Process ID (PID) is assigned to both the Kernel and WebRunner. These PIDs are stored in the separate PID files for Kernel and WebRunner. The PID file for Kernel is kernel.pid and the PID file for WebRunner is webrunner.pid.
These files can be accessed from the following location:
The Linux users can use these PID files to read the PID assigned to the Kernel or the WebRunner. These PIDs can be further used in the Adeptia Suite.
Whenever you stop the Kernel or the WebRunner, these PID files are automatically deleted by the OS. However, in case of unexpected system shutdown or in case the Kernel and WebRunner are stopped unexpectedly, you need to manually delete these PID files. In case, you do not delete these PID files, the following error message is displayed:
"PID file already exists."
You then will be required to delete the PID files, restart the system or the Kernel and WebRunner and only then you can proceed further.