#+title: Migrating to a New Web Server Setup with Debian, Nginx, and Agate
#+date: 2022-02-16
#+description: A retrospective on my recent server migration.
#+filetags: :sysadmin:

* Server OS: Debian
#+caption: Debian + neofetch
[[https://img.cleberg.net/blog/20220216-migrating-to-debian-and-nginx/neofetch.png]]

I've used various Linux distributions throughout the years, but I've
never used anything except Ubuntu for my servers. Why? I really have no
idea, mostly just comfort around the commands and software availability.

However, I have always wanted to try Debian as a server OS after testing
it out in a VM a few years ago (side-note: I'd love to try Alpine too,
but I always struggle with compatibility). So, I decided to launch a new
VPS and use [[https://www.debian.org][Debian]] 11 as the OS. Spoiler
alert: it feels identical to Ubuntu for my purposes.

I did the normal things when first launching the VPS, such as adding a
new user, locking down SSH, etc. If you want to see that level of
detail, read my other post about
[[https://cleberg.net/blog/how-to-set-up-a-vps-web-server/][How to Set
Up a VPS Web Server]].

All of this has been similar, apart from small things such as the
location of users' home folders. No complaints at all from me - Debian
seems great.

* Web Server: Nginx
#+caption: Nginx status
[[https://img.cleberg.net/blog/20220216-migrating-to-debian-and-nginx/nginx.png]]

Once I had the baseline server configuration set-up for Debian, I moved
on to trying out [[https://nginx.org][Nginx]] as my web server software.
This required me to install the =nginx= and =ufw= packages, as well as
setting up the initial UFW config:

#+begin_src sh
sudo apt install nginx ufw
sudo ufw allow 'Nginx Full'
sudo ufw allow SSH
sudo ufw enable
sudo ufw status
sudo systemctl status nginx
#+end_src

Once I had the firewall set, I moved on to creating the directories and
files for my website. This is very easy and is basically the same as
setting up an Apache server, so no struggles here.

#+begin_src sh
sudo mkdir -p /var/www/your_domain/html
sudo chown -R $USER:$USER /var/www/your_domain/html
sudo chmod -R 755 /var/www/your_domain
nano /var/www/your_domain/html/index.html
#+end_src

The next part, creating the Nginx configuration files, is quite a bit
different from Apache. First, you need to create the files in the
=sites-available= folder and symlink it the =sites-enabled= folder.

Creating the config file for your domain:

#+begin_src sh
sudo nano /etc/nginx/sites-available/your_domain
#+end_src

Default content for an Nginx config file:

#+begin_src sh
server {
        listen 80;
        listen [::]:80;

        root /var/www/your_domain/html;
        index index.html index.htm index.nginx-debian.html;

        server_name your_domain www.your_domain;

        location / {
                try_files $uri $uri/ =404;
        }
}
#+end_src

Finally, symlink it together:

#+begin_src sh
sudo ln -s /etc/nginx/sites-available/your_domain /etc/nginx/sites-enabled/
#+end_src

This will make your site available to the public (as long as you have
=your_domain= DNS records pointed at the server's IP address)!

Next, I used [[https://certbot.eff.org/][certbot]] to issue an HTTPS
certificate for my domains using the following commands:

#+begin_src sh
sudo apt install snapd; sudo snap install core; sudo snap refresh core
sudo snap install --classic certbot
sudo ln -s /snap/bin/certbot /usr/bin/certbot
sudo certbot --nginx
#+end_src

Now that certbot ran successfully and updated my Nginx config files to
include a =443= server block of code, I went back in and edited the
config file to include security HTTP headers. This part is optional, but
is recommended for security purposes; you can even test a website's HTTP
header security at [[https://securityheaders.com/][Security Headers]].

The configuration below shows a set-up where you only want your website
to serve content from its own domain, except for images and scripts,
which may come from =nullitics.com=. All other content would be blocked
from loading in a browser.

#+begin_src sh
sudo nano /etc/nginx/sites-available/your_domain
#+end_src

#+begin_src sh
server {
    ...
        add_header Content-Security-Policy "default-src 'none'; img-src 'self' https://nullitics.com; script-src 'self' https://nullitics.com; style-src 'self'; font-src 'self'";
        add_header X-Content-Type-Options "nosniff";
        add_header X-XSS-Protection "1; mode=block";
        add_header X-Frame-Options "DENY";
        add_header Strict-Transport-Security "max-age=63072000; includeSubDomains";
        add_header Referrer-Policy "no-referrer";
    ...
}
#+end_src

#+begin_src sh
sudo systemctl restart nginx
#+end_src

** Nginx vs. Apache
As I stated at the beginning, my historical hesitation with trying Nginx
was that the differences in configuration formats scared me away from
leaving Apache. However, I prefer Nginx to Apache for a few reasons:

1. Nginx uses only one config file (=your_domain=) vs. Apache's two-file
   approach for HTTP vs. HTTPS (=your_domain.conf= and
   =your_domain-le-ssl.conf=).
2. Symlinking new configurations files and reloading Nginx are way
   easier than Apache's process of having to enable headers with
   =a2enmod mod_headers=, enable PHP with =a2enmod php= (plus any other
   mods you need), and then enabling sites with =a2ensite=, and THEN
   reloading Apache.
3. The contents of the Nginx config files seem more organized and
   logical with the curly-bracket approach. This is a minor reason, but
   everything just felt cleaner while I was installing my sites and that
   had a big quality of life impact on the installation for me.

They're both great software packages, but Nginx just seems more
organized and easier to use these days. I will certainly be exploring
the Nginx docs to see what other fun things I can do with all of this.

* Gemini Server: Agate
#+caption: Agate status
[[https://img.cleberg.net/blog/20220216-migrating-to-debian-and-nginx/agate.png]]

Finally, I set up the Agate software on this server again to host my
Gemini server content, using Rust as I have before. You can read my
other post for more information on installing Agate:
[[https://cleberg.net/blog/hosting-a-gemini-server/][Hosting a Gemini
Server]].

All in all, Debian + Nginx is very slick and I prefer it over my old
combination of Ubuntu + Apache (although it's really just Nginx > Apache
for me, since Debian seems mostly the same as Ubuntu is so far).