How to Install Passenger + Apache in Ubuntu 16.04 LTS

Note: This assumes that you already have a running Ubuntu server. To install basic security in Ubuntu, see Basic Security Installs for Ubuntu. This instructions was extracted from here.

1. Install Apache Server

     sudo apt-get update
     sudo apt-get install apache2
     

2. Set Global ServerName to Suppress Syntax Warnings: "AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.1.1. Set the 'ServerName' directive globally to suppress this message"

     sudo vim /etc/apache2/apache2.conf
     

   and enter at the end of the file:

     ServerName server_domain_or_IP
     

3. Test config so far

     sudo apache2ctl configtest
     

4. Restart Apache for the changes to take effect

     sudo systemctl restart apache2
     

5. Install Passenger packages.

   # Install our PGP key and add HTTPS support for APT
   sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 561F9B9CAC40B2F7
   sudo apt-get install -y apt-transport-https ca-certificates
   
   # Add our APT repository
   sudo sh -c 'echo deb https://oss-binaries.phusionpassenger.com/apt/passenger xenial main > /etc/apt/sources.list.d/passenger.list'
   sudo apt-get update
   
   # Install Passenger + Apache module
   sudo apt-get install -y libapache2-mod-passenger
   

   These commands will install Passenger + Apache module through Phusion's APT repository.
6. Enable the Passenger Apache module and restart Apache

   sudo a2enmod passenger
   sudo apache2ctl restart
   

7. Check installation

   sudo passenger-config validate-install
   

   All checks should pass. If any of the checks do not pass, please follow the suggestions on screen.
8. Check whether Apache has started the Passenger core processes by running the following:

   sudo passenger-memory-stats