Phusion Passenger & Nginx with Systemd Notes
The recommended way to add Nginx to systemd is via the following from https://www.nginx.com/resources/wiki/start/topics/examples/systemd/:
[Unit] Description=The NGINX HTTP and reverse proxy server After=syslog.target network.target remote-fs.target nss-lookup.target [Service] Type=forking PIDFile=/run/nginx.pid ExecStartPre=/usr/sbin/nginx -t ExecStart=/usr/sbin/nginx ExecReload=/bin/kill -s HUP $MAINPID ExecStop=/bin/kill -s QUIT $MAINPID PrivateTmp=true [Install] WantedBy=multi-user.target
However, if you’re using Phusion Passenger also and run the command sudo passenger-status, you may get the following error message:
ERROR: Phusion Passenger doesn't seem to be running. If you are sure that it is running, then the causes of this problem could be: 1. You customized the instance registry directory using Apache's PassengerInstanceRegistryDir option, Nginx's passenger_instance_registry_dir option, or Phusion Passenger Standalone's --instance-registry-dir command line argument. If so, please set the environment variable PASSENGER_INSTANCE_REGISTRY_DIR to that directory and run passenger-status again. 2. The instance directory has been removed by an operating system background service. Please set a different instance registry directory using Apache's PassengerInstanceRegistryDir option, Nginx's passenger_instance_registry_dir option, or Phusion Passenger Standalone's --instance-registry-dir command line argument.
This is because Phusion Passenger utilizes the /tmp directory, which has been modified via the systemd line above that reads PrivateTmp=true. So if you want Phusion Passenger to run without any problems, you’ll want to change PrivateTmp=true to PrivateTmp=false.
The correct systemd code for using Phusion Passenger with Nginx (and the default /opt/nginx path from the Phusion Passenger install) is:
[Unit] Description=The NGINX HTTP and reverse proxy server After=syslog.target network.target remote-fs.target nss-lookup.target [Service] Type=forking PIDFile=/opt/nginx/logs/nginx.pid ExecStartPre=/opt/nginx/sbin/nginx -t ExecStart=/opt/nginx/sbin/nginx ExecReload=/bin/kill -s HUP $MAINPID ExecStop=/bin/kill -s QUIT $MAINPID PrivateTmp=false [Install] WantedBy=multi-user.target
Update
Alternatively, as noted by Hongli Lai (the creator of Phusion Passenger) in the comments below, you can use the Phusion Passenger directive passenger_instance_registry_dir . For example, you can add the following line to your Nginx configuration file’s http block (assuming you’ve installed Nginx at /opt/nginx):
passenger_instance_registry_dir /opt/nginx/tmp;
You’ll first have to create the directory if it doesn’t exist (sudo mkdir /opt/nginx/tmp), and then specify the environment variable when running sudo passenger-status, for example:
PASSENGER_INSTANCE_REGISTRY_DIR=/opt/nginx/tmp sudo -E passenger-status