# How to deploy a Ruby on Rails application

> Deploy a Ruby on Rails application on Kualo hosting using cPanel's Ruby Selector and Phusion Passenger.

Source: https://www.kualo.com/knowledgebase/dev-languages/how-to-deploy-a-ruby-on-rails-application
Updated: 2026-06-09

---

This guide walks you through deploying a Ruby on Rails application on Kualo hosting, using Redmine as a worked example. If you have not yet enabled Ruby in cPanel, start with [Enabling Ruby in cPanel](/knowledgebase/ruby-on-rails/enabling-ruby-in-cpanel) before continuing.

:::info
Kualo hosting uses Phusion Passenger as the web server for Ruby applications. The Ruby Selector handles the setup for you: it adds the required Passenger directives to your `.htaccess` file and installs Ruby inside an isolated virtual environment.
:::

## What is Redmine?

Redmine is a flexible, open-source project management web application built with Ruby on Rails. It is cross-platform and supports multiple databases.

## Setting up the application in Ruby Selector

1. Open **Ruby Selector** in cPanel and add your application base folder.
2. Choose your Ruby version and set the application root path - for example, `/home/rubytest/myapps/redmine`.
3. Click **Setup**.

The selector creates three folders inside your application root by default: `tmp`, `public`, and `logs`. Any files that need to be publicly accessible must go inside the `public` folder.

![Ruby Selector base folder](https://kb-cdn.kualo.com/07/d0/07d0b05887a32d874f4e8b22aa144b2571835311.png)

After setup, the selector displays the command you need to activate the Ruby virtual environment via SSH.

![Ruby activation command](https://kb-cdn.kualo.com/50/a2/50a243980d238790ca26e5d80477f89ff318a926.png)

## Downloading Redmine

Connect to your account via SSH, then run the following commands to download and unpack Redmine into your application root:

```bash
cd myapps
wget https://www.redmine.org/releases/redmine-3.4.5.tar.gz
tar xvfz redmine-3.4.5.tar.gz
mv redmine-3.4.5/* redmine
rm -f redmine-3.4.5.tar.gz
```

Redmine already includes a `public` folder, so moving its contents directly into your application root is correct.

## Installing Redmine

### Step 1 - Create a database

Create a MySQL database and assign a user to it inside cPanel. Make a note of the database name, username, and password.

### Step 2 - Configure the database connection

1. Navigate to `myapps/redmine/config/`.
2. Copy `database.yml.example` to `database.yml`.
3. Edit `database.yml`, keeping only the `production` block and updating it with your database details:

```yaml
production:
  adapter: mysql2
  database: user_redmine
  host: localhost
  username: user_redmine
  password: my_password
```

### Step 3 - Activate Ruby and install Bundler

Bundler reads the `Gemfile` in your application root and installs all required gems. First, activate the Ruby virtual environment using the command shown by the Ruby Selector, then install Bundler:

```bash
source /home/rubytest/rubyvenv/myapps_redmine/2.4/bin/activate
gem install bundler
```

### Step 4 - Install dependencies

From the application root directory (where `Gemfile` is located), run:

```bash
bundle install --without development test
```

The `--without development test` flag tells Bundler to skip gems that are only needed for development and testing environments.

:::info
If Bundler cannot find the `Gemfile`, check that you are running the command from the correct directory.
:::

### Step 5 - Resolve missing gem errors

If you see an error such as `LoadError: cannot load such file -- bigdecimal`, a required gem is missing from the `Gemfile`. The most reliable fix is to add it explicitly rather than installing it outside Bundler.

1. Open `Gemfile` in your application root.
2. Add the missing gem, for example:

```ruby
gem "bigdecimal"
```

3. Run `bundle install` again to install the new dependency.

### Step 6 - Generate a secret token

This command generates a random key that Rails uses to sign and encrypt session cookies. Run it from the application root:

```bash
bundle exec rake generate_secret_token
```

Generating a new token will invalidate any existing sessions after the next restart.

### Step 7 - Set up the database schema

Create the database tables by running:

```bash
RAILS_ENV=production bundle exec rake db:migrate
```

### Step 8 - Load default data

Populate the database with Redmine's default configuration data:

```bash
RAILS_ENV=production bundle exec rake redmine:load_default_data
```

## Viewing your application

Once all steps are complete, visit your domain name in a browser. You should see your Ruby on Rails application running.

---

_Source: Kualo Knowledgebase — https://www.kualo.com/knowledgebase/dev-languages/how-to-deploy-a-ruby-on-rails-application · © Kualo Ltd._