Read configuration /home/pi/volkszaehler.org/etc/middleware.json, modified by command arguments.
/home/pi
+---------------------------+-----------------------------------------+
| host                      | 0.0.0.0                                 |
| port                      | 8080                                    |
| workers                   | 8                                       |
| static-directory          | /var/www/volkszaehler.org/htdocs        |
| logging                   | 0                                       |
| max-requests              | 1000                                    |
| bridge                    | HttpKernel                              |
| bootstrap                 | Volkszaehler\Server\PPMBootstrapAdapter |
| app-env                   | dev                                     |
| debug                     | 0                                       |
| max-execution-time        | 30                                      |
| memory-limit              | -1                                      |
| limit-concurrent-requests |                                         |
| request-body-buffer       |                                         |
| ttl                       | 0                                       |
| populate-server-var       | 1                                       |
| socket-path               | .ppm/run/                               |
| pidfile                   | .ppm/ppm.pid                            |
| reload-timeout            | 30                                      |
| cgi-path                  | /usr/bin/php                            |
+---------------------------+-----------------------------------------+

In TcpServer.php line 165:
                                                                    
  Failed to listen on "tcp://0.0.0.0:8080": Address already in use  
                                                                    

start [--bridge BRIDGE] [--host HOST] [--port PORT] [--workers WORKERS] [--app-env APP-ENV] [--debug DEBUG] [--logging LOGGING] [--static-directory STATIC-DIRECTORY] [--max-requests MAX-REQUESTS] [--max-execution-time MAX-EXECUTION-TIME] [--memory-limit MEMORY-LIMIT] [--limit-concurrent-requests LIMIT-CONCURRENT-REQUESTS] [--request-body-buffer REQUEST-BODY-BUFFER] [--ttl TTL] [--populate-server-var POPULATE-SERVER-VAR] [--bootstrap BOOTSTRAP] [--cgi-path CGI-PATH] [--socket-path SOCKET-PATH] [--pidfile PIDFILE] [--reload-timeout RELOAD-TIMEOUT] [-c|--config CONFIG] [--] [<working-directory>]

Server is shutting down.
Stopping the process manager.
PHP Fatal error:  Uncaught ErrorException: Warning: file_get_contents(.ppm/ppm.pid): failed to open stream: No such file or directory in /home/pi/volkszaehler.org/vendor/php-pm/php-pm/src/ProcessManager.php:562
Stack trace:
#0 /home/pi/volkszaehler.org/vendor/php-pm/php-pm/src/ProcessManager.php(311): PHPPM\ProcessManager->removePidFile()
#1 /home/pi/volkszaehler.org/vendor/php-pm/php-pm/src/ProcessManager.php(268): PHPPM\ProcessManager->quit()
#2 [internal function]: PHPPM\ProcessManager->shutdown()
#3 {main}
  thrown in /home/pi/volkszaehler.org/vendor/php-pm/php-pm/src/ProcessManager.php on line 562