Managing Nginx Processes

The second in a series of Nginx posts.

Nginx runs two different types of processes: the master process and worker processes.

Master Process

This should be started as root, because this will allow Nginx to open sockets below 1024 (it needs to be able to listen on port 80 for HTTP and 443 for HTTPS).

Worker Processes

These are spawned by the master process, and the user and group will as specified

The Nginx binary accepts command-line arguments, of which a full list can be obtained by:

/usr/local/nginx/sbin $ ./nginx -h

-V tells you about Nginx as well as the options it was built with:

$ nginx -V
nginx version: nginx/1.4.6 (Ubuntu)
built by gcc 4.8.2 (Ubuntu 4.8.2-19ubuntu1)
TLS SNI support enabled
configure arguments: --with-cc-opt='-g -O2 -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security -D_FORTIFY_SOURCE=2' --with-ld-opt='-Wl,-Bsymbolic-functions -Wl,-z,relro' --prefix=/usr/share/nginx --conf-path=/etc/nginx/nginx.conf ... (redacted) ...

Starting

To start Nginx, simply run the binary without any switches:

/usr/local/nginx/sbin $ ./nginx

Stopping

There are two ways to stop Nginx - immediately using the TERM signal, or gracefully using the QUIT signal:

/usr/local/nginx/sbin $ ./nginx -s stop

/usr/local/nginx/sbin $ ./nginx -s quit

Reloading Configuration

/usr/local/nginx/sbin $ ./nginx -s reload

All of the above commands will verify the configuration file each time they are run, even when you’re trying to stop Nginx. When you’re unable to stop Nginx using ./nginx -s stop, you may use kill or killall:

$ killall nginx

Testing Your Configuration

Optionally, you can specify a path with -c so that you can test another configuration file:

$ ./nginx -t -c /home/siawyoung/test.conf

#Nginx as a system service

Adding Nginx as a system service allows us to:

1. Control it with standard commands
2. Have it launch and quit at system startup and shutdown automatically

To add Nginx as a system service, we simply need to include a script in /etc/init.d/ called nginx¹. There’re many resources out there which covers Nginx init scripts.

This one seems quite popular and well-documented. Install it into your etc/init.d and make the script executable:

$ sudo wget https://raw.github.com/JasonGiedymin/nginx-init-ubuntu/master/nginx -O /etc/init.d/nginx
$ sudo chmod +x /etc/init.d/nginx

Then, we need to associate the script with the operation system’s default runlevel² so that the system runs this script on startup:

$ sudo update-rc.d -f nginx defaults

At this point, you should be able to start, stop, restart, or poll for Nginx status (assuming you used the script above):

$ service nginx start # or stop | restart | status