Using linger with Ruby on Rails

How do I install Ruby and Rails?

Ruby: View the Ruby Version Manager (RVM) article to install a new version of Ruby on your Managed VPS.

Rails: View steps #1-7.3 in this guide to configure Rails. The guide uses the Rails app name of blog, but you can name it anything you like.

How do I install Puma?

View the following guides for steps on installing Puma:

• github.com/puma/puma
• rubygems.org/gems/puma

Edit the puma.rb file

Navigate into the following directory:

[server]$ cd /home/username/example.com/blog/config

Edit the puma.rb file to change the default port # to the port you chose when creating the Proxy Server in the panel. This example uses port 8003:

port ENV.fetch("PORT") {8003}

Start the Puma web server

Navigate into the following directory:

[server]$ cd /home/username/example.com/blog/

Run the following command:

[server]$ bin/rails server

To stop the server, press CTRL + C.

Troubleshooting an error

If you get a blocked host error about your app domain, you'll need to add a line to the development.rb file. Navigate into the following directory:

[server]$ cd /home/username/example.com/blog/config/environments/

Edit the development.rb file. Under the config.enable_reloading = true line, add the following:

config.hosts << /example\.com/

Restart your Managed VPS and relaunch Puma. The error should now be resolved.

How do I install Linger?

To install linger under your user, log in to your server via SSH and run the following command:

[server]$ loginctl enable-linger

How do I configure Puma for Systemd user units?

This step configures Puma for Systemd user units. View the official guide for further details.

1. Create a file named puma.service in the .config/systemd/user directory:

   [server]$ nano ~/.config/systemd/user/puma.service

2. Add the following code to this file:

   [Unit]
   Description=Puma instance to serve application
   After=network.target
   
   [Service]
   WorkingDirectory=/path/to/your/app
   ExecStart=/path/to/your/app/bin/puma -C config/puma.rb -e production
   ExecReload=/bin/kill -s HUP $MAINPID
   KillMode=mixed
   TimeoutStopSec=5
   PrivateTmp=true
   Restart=on-failure
   
   [Install]
   WantedBy=default.target

3. Edit the highlighted lines above as follows:

   • WorkingDirectory: The path to your website application.
   • ExecStart: The path to your puma installation.

   If you are using a custom environment for your Ruby/Puma setup, be sure to define your environment directory paths in the [Service] section of your Linger Systemd service file.

   [Unit]
   Description=Puma server to serve application
   After=network.target
   
   [Service]
   WorkingDirectory=/path/to/your/app
   ExecStart=/path/to/your/app/bin/puma  -C config/puma.rb -e production
   ExecReload=/bin/kill -s HUP $MAINPID
   Environment=GEM_PATH=/path/to/your/.rvm/gem-VERSION@global
   Environment=GEM_HOME=/path/to/your/.rvm/gems/ruby-VERSION
   Environment=PATH=/path/to/your/.rvm/gems/ruby-VERSION/bin:/path/to/your/.rvm/gem-VERSION@global/bin:/path/to/your..rvm/rubies/ruby-VERSION/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/APP:/usr/local/APP:/snap/bin:/path/to/your/.rvm/bin
   KillMode=mixed
   TimeoutStopSec=5
   PrivateTmp=true
   Restart=on-failure
   PIDFile=/tmp/puma.pid
   
   [Install]
   WantedBy=default.target

4. Enable the user unit for puma:

   [server]$ systemctl --user enable puma

5. Start the unit with puma:

   [server]$ systemctl --user start puma

6. Confirm it is running:

   [server]$ systemctl --user status puma