Tomcat startup parameter specifies the port by way of

1. The start port is modified in server.xml variable placeholders.

<Connector port="${http.port}" protocol="HTTP/1.1"
               connectionTimeout="20000"
               redirectPort="8443" />

2. First start the next test, as expected, it failed.
   
3. Increase in the startup.sh

JAVA_OPTS="$JAVA_OPTS  -Dhttp.port='50000'"

4. start up.