Phusion Passenger opens random ports

Question

I'm experiencing same problem as described here Strange public listening ports in Passenger.

Phusion Passenger is randomly opening ports and I have no idea how to further investigate it.

• Passenger Version : 6.0.14
• ruby-2.4.1
• nginx version: nginx/1.20.2
• Ubuntu 18.04.6 LTS
• Linux 4.15.0-192-generic

netstat -lp
tcp        0      0 localhost:45363         0.0.0.0:*               LISTEN      13226/Passenger Rub
tcp        0      0 localhost:34515         0.0.0.0:*               LISTEN      7653/Passenger Ruby

ps -p 7653 -o pid,vsz=MEMORY -o user,group=GROUP -o comm,args=ARGS
7653 427776 user1    user1    ruby            Passenger RubyApp: /home/user1/apps/application1/current (production)

Thank you in advance for any tips how to solve this problem.

Answer 1

It looks like this is by design. They can be used to manage the associated backend apps in some ways. See here: https://github.com/phusion/passenger/pull/2173 for a discussion.