Since this post shares cloud strategies with awesome people like you, naturally this post may contain affiliate links for products I use and love. If you click on those links and make a purchase, I'll earn some coffee money which I promise to drink while creating more helpful content like this.

In this post, I will help you install CodeIgniter on Google Cloud with Ubuntu 18.04 LTS, Nginx + FastCGI, PHP 7.2, Cloud SQL.

Prerequisites

1. Your Compute Engine Instance running.
2. For setting up Compute Engine, see the Setting up Compute Engine Instance.
3. For installing Nginx and PHP, see how to install LEMP in Compute Engine Instance.
4. Domain name is pointed to your virtual machine.
5. For setting up Cloud DNS, see the Setting up Google Cloud DNS for your domain.
6. Google Cloud SQL Setup, see Setup Cloud SQL and connect with Compute Engine.

Setup your website

Your website will be located in the home directory and have the following structure

Replace yourdomainname.com with your original domain name.

home
    -- yourdomainname.com
        ---- logs
        ---- public

The public directory is your website’s root directory and logs directory for your error logs

Now we create these directories and set correct permissions

You need to SSH into your VM Instance and run these commands

mkdir -p yourdomainname.com/logs yourdomainname.com/public
sudo chmod -R 755 yourdomainname.com

Download CodeIgniter

Make sure you follow the above prerequisites to set up your server in Google Cloud.

Now that your server software is configured, you can download and set up CodeIgniter.

It is always recommended to get the latest version of CodeIgniter

Access SSH in your Compute Engine Instance and navigate to your root directory and download CodeIgniter.

cd ~/yourdomainname.com/public
curl -LO https://github.com/bcit-ci/CodeIgniter/archive/3.1.9.tar.gz

This command will download the latest version and it needs to be extracted.

tar xzvf 3.1.9.tar.gz

Now, you can copy the entire contents of the directory into our document root.

sudo cp -a ~/yourdomainname.com/public/CodeIgniter-3.1.9/. ~/yourdomainname.com/public

Next cleanup your root directory by deleting the codeigniter folder and the downloaded tar file.

sudo rm -r ~/yourdomainname.com/public/CodeIgniter-3.1.9
sudo rm -f ~/yourdomainname.com/public/3.1.9.tar.gz 

Set correct permissions for the root folder. Don’t forget to replace yourdomainname.com with your domain name

sudo chown -R username ~/yourdomainname.com/public

NGINX configuration for CodeIgniter

Now create a new Nginx configuration for your website in the sites-available directory

sudo nano /etc/nginx/sites-available/yourdomainname.com

Copy and paste the following configuration, ensure that you change the server_name, error_log and root directives to match your domain name. Hit CTRL+X followed by Y to save the changes.

server {
    listen 80;
    listen [::]:80;
    
    server_name yourdomainname.com www.yourdomainname.com;
    
    error_log /home/username/yourdomainname.com/logs/error.log;

    root /home/username/yourdomainname.com/public/;
    index index.html index.php;

    location / {
        try_files $uri $uri/ /index.php?$args;
    }

    location ~ \.php$ {
        try_files $uri =404;
        fastcgi_split_path_info ^(.+\.php)(/.+)$;
        fastcgi_pass unix:/run/php/php7.2-fpm.sock;
        fastcgi_index index.php;
        include fastcgi_params;
    }
}

To enable this newly created website configuration, symlink the file that you just created into the sites-enabled directory.

sudo ln -s /etc/nginx/sites-available/yourdomainname.com /etc/nginx/sites-enabled/yourdomainname.com

Check your configuration and restart Nginx for the changes to take effect

sudo nginx -t
sudo service nginx restart

Create SSL certificate and enable HTTP/2

HTTPS
HTTPS is a protocol for secure communication between a server (instance) and a client (web browser). Due to the introduction of Let’s Encrypt, which provides free SSL certificates, HTTPS are adopted by everyone and also provides trust to your audiences.

HTTP/2
HTTP/2 is the latest version of the HTTP protocol and can provide a significant improvement to the load time of your sites. There really is no reason not to enable HTTP/2, the only requirement is that the site must use HTTPS.

sudo add-apt-repository ppa:certbot/certbot
sudo apt update
sudo apt install python-certbot-nginx

Now we have installed Certbot by Let’s Encrypt for Ubuntu 18.04, run this command to receive your certificates.

sudo certbot --nginx certonly

Enter your email and agree to the terms and conditions, then you will receive the list of domains you need to generate SSL certificate.

To select all domains simply hit Enter

The Certbot client will automatically generate the new certificate for your domain. Now we need to update the Nginx config.

Redirect HTTP Traffic to HTTPS with www in Nginx

Open your site’s Nginx configuration file add replace everything with the following. Replacing the file path with the one you received when obtaining the SSL certificate. The ssl_certificate directive should point to your fullchain.pem file, and the ssl_certificate_key directive should point to your privkey.pem file.

server {
    listen [::]:80;
    listen 80;     

    server_name yourdomainname.com www.yourdomainname.com;     

    # redirect http to https www     
    return 301 https://www.yourdomainname.com$request_uri; 
} 

server {     
    listen [::]:443 ssl http2;     
    listen 443 ssl http2;
    
    server_name yourdomainname.com;

    ssl_certificate /etc/letsencrypt/live/yourdomainname.com/fullchain.pem;     
    ssl_certificate_key /etc/letsencrypt/live/yourdomainname.com/privkey.pem;     

    root /home/username/yourdomainname.com/public/; 
    index index.html index.php; 

    # redirect https non-www to https www 
    return 301 https://www.yourdomainname.com$request_uri; 
}

server { 
    listen [::]:443 ssl http2; 
    listen 443 ssl http2; 

    server_name www.yourdomainname.com; 

    ssl_certificate /etc/letsencrypt/live/yourdomainname.com/fullchain.pem;     
    ssl_certificate_key /etc/letsencrypt/live/yourdomainname.com/privkey.pem;     

    error_log /home/username/yourdomainname.com/logs/error.log; 

    root /home/username/yourdomainname.com/public/; 
    index index.html index.php; 

    location / { 
        try_files $uri $uri/ /index.php?$args; 
    } 

    location ~ \.php$ { 
        try_files $uri =404; 
        fastcgi_split_path_info ^(.+\.php)(/.+)$; 
        fastcgi_pass unix:/run/php/php7.2-fpm.sock; 
        fastcgi_index index.php; 
        include fastcgi_params; 
        add_header Content-Security-Policy "img-src * 'self' data: blob: https:; default-src 'self' https://*.googleapis.com https://*.googletagmanager.com https://*.google-analytics.com https://s.ytimg.com https://www.youtube.com https://www.yourdomainname.com https://*.googleapis.com https://*.gstatic.com https://*.gravatar.com https://*.w.org data: 'unsafe-inline' 'unsafe-eval';" always; 
        add_header X-Xss-Protection "1; mode=block" always; 
        add_header X-Frame-Options "SAMEORIGIN" always; 
        add_header X-Content-Type-Options "nosniff" always; 
        add_header Access-Control-Allow-Origin "https://www.yourdomainname.com";         
        add_header Referrer-Policy "origin-when-cross-origin" always;         
        add_header Strict-Transport-Security "max-age=31536000; includeSubdomains; preload"; 
    }
}

The http2 value is all that is needed to enable the HTTP/2 protocol.

Now you have enabled SSL Hardening, created a Content Security Policy, X-XSS-Protection, Clickjacking, MIME Sniffing, Referrer Policy, Access Control Allow Origin.

These are some Nginx security tweaks by closing all areas of attacks.

Hit CTRL+X followed by Y to save the changes.

Check your configuration and restart Nginx for the changes to take effect.

sudo nginx -t
sudo service nginx restart

Renewing SSL Certificate

Certificates provided by Let’s Encrypt are valid for 90 days only, so you need to renew them often. Now you set up a cronjob to check for the certificate which is due to expire in next 30 days and renew it automatically.

sudo crontab -e

Add this line at the end of the file

0 0,12 * * * certbot renew >/dev/null 2>&1

Hit CTRL+X followed by Y to save the changes.

This cronjob will attempt to check for renewing the certificate twice daily.

Once the setup is done visit your domain in your web browser. You can now view the default Welcome page of CodeIgniter.

Connect CodeIgniter with Google Cloud SQL

Make sure you have created Cloud SQL and connected to Compute Engine VM Instance as documented in the 6th point of prerequisites.

Now open your database configuration file in CodeIgniter and update the values of CodeIgniter

sudo nano ~/yourdomainname.com/public/application/config/database.php

Update the following values with your Cloud SQL settings

'hostname' => 'CLOUD_SQL_INSTANCE_IP_ADDRESS',
'username' => 'USERNAME', 
'password' => 'PASSWORD', 
'database' => 'DATABASE_NAME',

Save and close the file.

Congratulations! you have successfully installed CodeIgniter on Ubuntu 18.04 LTS server with Nginx, PHP 7.2 and Google Cloud SQL