Sampleruntime might crash at boot when an additional App is installed

[OWarneke]

FW Version: 2021.0
PLC: AXC F 2152

If the System is under heavy load at boot it might happen that the Runtime startup is delayed.
This results in a timeout of the FW process.

19.01.21 11:48:50.052 Arp.System.Acf.Internal.Sm.ProcessesController               ERROR - Could not start process 'runtime'.
19.01.21 11:48:50.059 Arp.System.Acf.Internal.ApplicationBase                      FATAL - Fatal error occurs in application 'MainProcess':
19.01.21 11:48:50.061 Arp.System.Acf.Internal.ApplicationBase                      FATAL - Exception occurs: Exception of type 'Arp::System::Commons::InvalidOperationException' was thrown
Could not start all processes
    at Arp::System::Acf::Internal::Sm::ProcessesController::StartProcesses()
    at Arp::System::Acf::Internal::Sm::SystemManager::SetupSystemSettings()
    at Arp::System::Acf::Internal::Sm::SystemManager::SetupSystem()
    at Arp::System::Acf::Internal::ApplicationBase::SetupBasicComponents(Arp::System::Acf::Internal::ApplicationSetupKind, Arp::System::Acf::Internal::ProcessKind)
    at Arp::System::Acf::Internal::ApplicationBase::Setup(Arp::System::Commons::Diagnostics::Logging::LogLevel, char const*)
    at Arp::System::Acf::Internal::ApplicationBase::Main(int, char**, Arp::System::Commons::Diagnostics::Logging::LogLevel)
    at Arp.System.Application(+0x2000c) [0x42800c]
    at /lib/libc.so.6(__libc_start_main+0x97) [0xb67009a4]
19.01.21 11:48:50.066 Arp.System.Acf.Internal.ApplicationBase                      INFO  - Application 'ExternalIoProcess' terminates.

[OWarneke]

This is error shows up due to a timeout in the PLCnext Runtime boot process.
The Timeout is caused by some non PLCnext Runtime Processes blocking the PLCnext runtime with a high/equal priority.

By fixing the init.d script of said processes to wait for the PLCnext Runtime start or starting these additional processes way before or after the PLCnext Runtime it is possible to fix this issue.

Possible workaround

@/etc/init.d/SomeScriptThatBlockstheFW.

...
start(){
...
sleep 10
start_daemon_command

}

You need to be carefull when running other applications then the PLCnext Runtime with Realtime priorities those applications might block the PLCnext Runtime.

This is not a defect of the SampleRuntime example -> wont fix here.

Later PLCnext Runtime versions offer the possibility to increase the Timeout value.