PassengerWatchdog

Hi,
i just set up a new server running debain 8.9 and ISPConfig Stable version 3.1.8. using the tutorial - The Perfect Server - Debian 8.4 Jessie (Apache2, BIND, Dovecot, ISPConfig 3.1)

I noticed strange directory in /tmp "passenger.(random number)" created at 4:33 AM and got a little scared because I never saw this before in the older version of Debian 7 and ISPConfig 3.0.5.3
The contents were with some txt files ie. "admin-manipulation-password.txt" etc. After reasearch it seems this is a Apache2 module "libapache2-mod-passenger". And there are some apache error.log entires lke this:

Code:

[Fri Nov 17 04:33:02.824904 2017] [:notice] [pid 15669] FastCGI: process manager initialized (pid 15669)
[ 2017-11-17 04:33:02.8384 15673/7f92108d5740 agents/Watchdog/Main.cpp:538 ]: Options: { 'analytics_log_user' => 'nobody', 'default_group' => 'nogroup', 'default_python' => 'python', 'default_ruby' => '/usr/bin/ruby', 'default_user' => 'nobody', 'log_level' => '0', 'max_pool_size' => '6', 'passenger_root' => '/usr/lib/ruby/vendor_ruby/phusion_passenger/locations.ini', 'passenger_version' => '4.0.53', 'pool_idle_time' => '300', 'temp_dir' => '/tmp', 'union_station_gateway_address' => 'gateway.unionstationapp.com', 'union_station_gateway_port' => '443', 'user_switching' => 'true', 'web_server_passenger_version' => '4.0.53', 'web_server_pid' => '28838', 'web_server_type' => 'apache', 'web_server_worker_gid' => '33', 'web_server_worker_uid' => '33' }
[ 2017-11-17 04:33:02.8518 15676/7ff45c0e1740 agents/HelperAgent/Main.cpp:650 ]: PassengerHelperAgent online, listening at unix:/tmp/passenger.1.0.28838/generation-3/request
[ 2017-11-17 04:33:02.8658 15682/7fdc7ddbb780 agents/LoggingAgent/Main.cpp:321 ]: PassengerLoggingAgent online, listening at unix:/tmp/passenger.1.0.28838/generation-3/logging
[ 2017-11-17 04:33:02.8731 15673/7f92108d5740 agents/Watchdog/Main.cpp:728 ]: All Phusion Passenger agents started!

Checking the running proceses I aslo see that several instances of "PassengerWatchdog", "PassengerHelperAgent", and "PassengerLogingAgent" are running for user root and nobody.

Searching the forums I can find some similar log entries in various posts but only some vague information. One post said passenger was not part of ISPConfig3 but I notice in the tutorial the libapache2-mod-passenger mod is installed. One other post mentioned this is related to Let's Encrypt. Which is also installed in the tutorial.

I deleted the folder in /tmp and noticed that after a dialog message appears in ISPConfig3 backend, the directory is recreated under a differnt random number. So it appears to be related to ISPConfig3.

So my question is what exactly is this Passenger / Watchdog ? Is it part of ISPConfig? Is it needed by ISPConfig? I hope I didn't miss any information about this somehwere, I wasn not able to find any documentation related to this.

Thanks!

 

Ok thanks for the reply.

So I'm safe in assuming that by installing that libapache2-mod-passenger with apache2 and then activating the mod, those services were automatically started? and this is normal behavior?

Code:

 5282 root       20   0  217M  1968  1648 S  0.0  0.0  0:00.00 PassengerWatchdog
5296 root       20   0  217M  1968  1648 S  0.0  0.0  0:00.00 PassengerWatchdog
5297 root       20   0  217M  1968  1648 S  0.0  0.0  0:00.00 PassengerWatchdog
5280 root       20   0  217M  1968  1648 S  0.0  0.0  0:00.00 PassengerWatchdog
5285 root       20   0  500M  2356  1984 S  0.0  0.0  0:00.00 PassengerHelperAgent
5286 root       20   0  500M  2356  1984 S  0.0  0.0  0:00.64 PassengerHelperAgent
5287 root       20   0  500M  2356  1984 S  0.0  0.0  0:00.00 PassengerHelperAgent
5291 root       20   0  500M  2356  1984 S  0.0  0.0  0:00.00 PassengerHelperAgent
5292 root       20   0  500M  2356  1984 S  0.0  0.0  0:00.00 PassengerHelperAgent
5293 root       20   0  500M  2356  1984 S  0.0  0.0  0:00.00 PassengerHelperAgent
5294 nobody     20   0  221M  4888  3692 S  0.0  0.0  0:00.00 PassengerLoggingAgent
5295 nobody     20   0  221M  4888  3692 S  0.0  0.0  0:00.00 PassengerLoggingAgent
5289 nobody     20   0  221M  4888  3692 S  0.0  0.0  0:00.05 PassengerLoggingAgent

-Thanks!