This tutorial uses a simple Node.js application, but is applicable to most, if not all, others as well (be they Ruby, Python, etc). For PHP web applications, it is recommended to use a more specialized LAMP or LEMP stack instead.

Commands will be provided for both Fedora and Arch, do keep a lookout for which is which to avoid misconfiguration and/or confusion. When not indicated, the command is the same for both systems. It is also recommended you read through the entire tutorial before attempting it step-by-step, so as to get an idea of what it entails and whether it is appropriate for your situation.

System Preliminaries

—
- A server withsystemd. Arch Linux and Fedora server instance are configured thus by default, but systemd can be installed on other distributions as well; refer to yours' documentation: Ubuntu, Debian.

• Nginx, to be used as a reverse-proxy http and websocket server.

• Git, to install nvm, and to pull your application if using git.

• Root access. It is also possible to login as a normal user and sudo all commands, or to su -or sudo su - to a root prompt.

Install packages

—
Arch:

# pacman -Sy
# pacman -S nginx git

Fedora:

# yum install nginx git

Application Preliminaries

—
These are settings you can customise to your liking, but they have to be decided upon and set before starting.

User

—
The application will run in its own separate user account. Pick a name, it should relate to the application to make it easy to remember and maintain. Here, srv-node-sample is used.

# useradd -mrU srv-node-sample

Port

—
To avoid conflicts, pick a high port. Here, "15301” is used.

Application Setup

—
Start by installing what is necessary for the application to run. For Node.js (and Ruby, Python...), there are two choices: either use the system's runtime, or a user-specific installation (e.g. using nvm, rbenv, RVM, virtualenv, etc).

Using the system node

—
Arch:

# pacman -S nodejs

Fedora:

# yum install nodejs

Using a user-specific install

—
This has to be installed in the application's home directory, i.e./home/srv-node-sample, which is most easily done by logging in as that user:

# su srv-node-sample

$ cd
$ curl https://raw.github.com/creationix/nvm/master/install.sh | sh
$ source ~/.nvm/nvm.sh
$ nvm install 0.10
$ nvm alias default 0.10

Then take note of where the node binary is installed:

$ which node
/home/srv-node-sample/.nvm/v0.10.22/bin/node

Deploy your application

—
While logged in tosrv-node-sample, deploy your code. This is an example only, your process will vary.

$ git clone [email protected]:user/repo.git .
$ npm install
$ grunt deploy

For this tutorial, the following sample application is used:

var http = require('http');
http.createServer(function(req, res) {
    res.end('<h1>Hello, world.</h1>');
}).listen(15301);

Then return to root:

$ exit

Nginx Setup

—
Place this in your server block:

location / {
    proxy_pass http://localhost:15301/;
    proxy_set_header Host $host;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
}

Then set up its daemon:

# systemctl enable nginx
# systemctl restart nginx

Systemd Setup

—
Create a service file for the application, in/etc/systemd/system/node-sample.service.

There's a few variables that need to be filled in:

• [node binary] This is the output of "which node” as the srv-node-sample user. Either/usr/bin/nodeor the~/.nvm/...path noted above.

• [main file] This is the main file of your application. Here, ‘index.js`.

• Don't forget to replacesrv-node-sample!

[Service]
ExecStart=[node binary] /home/srv-node-sample/[main file]
Restart=always
StandardOutput=syslog
StandardError=syslog
SyslogIdentifier=node-sample
User=srv-node-sample
Group=srv-node-sample
Environment=NODE_ENV=production

[Install]
WantedBy=multi-user.target

Now start the service:

# systemctl enable node-sample
# systemctl start node-sample

Usage

—

Status

—
~~~~

systemctl status node-sample

node-sample.service
Loaded: loaded (/etc/systemd/system/node-sample.service; enabled)
Active: active (running) since Fri 2013-11-22 01:12:15 UTC; 35s ago
Main PID: 7213 (node)
CGroup: name=systemd:/system/node-sample.service
└─7213 /home/srv-node-sample/.nvm/v0.10.22/bin/node /home/srv-nod...

Nov 22 01:12:15 d02 systemd[1]: Started node-sample.service.
~~~~

Logs

—
~~~~

journalctl -u node-sample

-- Logs begin at Thu 2013-11-21 19:05:17 UTC, end at Fri 2013-11-22 01:12:15 UTC. --
Nov 22 01:12:15 d02 systemd[1]: Starting node-sample.service...
Nov 22 01:12:15 d02 systemd[1]: Started node-sample.service.
Nov 22 01:12:30 d02 node-sample[7213]: Sample message from application
~~~~

Restart, stop, etc

—
Force a restart:

# systemctl restart node-sample

Stop the application:

# systemctl stop node-sample

The application will be automatically restarted if it dies or is killed:

# systemctl status node-sample
node-sample.service
   Loaded: loaded (/etc/systemd/system/node-sample.service; enabled)
   Active: active (running) since Fri 2013-11-22 01:12:15 UTC; 35s ago
 Main PID: 7213 (node)
   CGroup: name=systemd:/system/node-sample.service
           └─7213 /home/srv-node-sample/.nvm/v0.10.22/bin/node /home/srv-nod...

Nov 22 01:12:15 d02 systemd[1]: Started node-sample.service.

# kill 7213

# systemctl status node-sample
node-sample.service
   Loaded: loaded (/etc/systemd/system/node-sample.service; enabled)
   Active: active (running) since Fri 2013-11-22 01:54:37 UTC; 6s ago
 Main PID: 7236 (node)
   CGroup: name=systemd:/system/node-sample.service
           └─7236 /home/srv-node-sample/.nvm/v0.10.22/bin/node /home/srv-nod...

Nov 22 01:54:37 d02 systemd[1]: node-sample.service holdoff time over, sch...t.
Nov 22 01:54:37 d02 systemd[1]: Stopping node-sample.service...
Nov 22 01:54:37 d02 systemd[1]: Starting node-sample.service...
Nov 22 01:54:37 d02 systemd[1]: Started node-sample.service.

The PID has changed, showing the application has indeed been killed and restarted.

Websockets

—
If the application uses websockets, the following lines have to be added to the Nginx configuration:

proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
proxy_http_version 1.1;

and Nginx has to be reloaded:

# systemctl reload nginx