Automating Installation of WordPress with NGINX Unit on Ubuntu

ubuntu_install.sh

#!/usr/bin/env bash

if [ "$EUID" -ne 0 ];then
  >&2 echo "This script requires root level access to run"
  exit 1
fi

if [ -z "${WORDPRESS_DB_PASSWORD}" ]; then
  >&2 echo "WORDPRESS_DB_PASSWORD must be set"
  >&2 echo "Here is a random one that you can paste:"
  >&2 echo "export WORDPRESS_DB_PASSWORD=\"$(cat /dev/urandom | tr -dc 'a-zA-Z0-9' | fold -w 32 | head -n 1)\""
  exit 1
fi

if [ -z "${WORDPRESS_ADMIN_USER}" ]; then
  >&2 echo "WORDPRESS_ADMIN_USER must be set"
  >&2 echo "Here is a sensible default that you can paste:"
  >&2 echo "export WORDPRESS_ADMIN_USER=\"moderator\""
  exit 1
fi

if [ -z "${WORDPRESS_ADMIN_PASSWORD}" ]; then
  >&2 echo "WORDPRESS_ADMIN_PASSWORD must be set"
  >&2 echo "Here is a random one that you can paste:"
  >&2 echo "export WORDPRESS_ADMIN_PASSWORD=\"$(cat /dev/urandom | tr -dc 'a-zA-Z0-9' | fold -w 32 | head -n 1)\""
  exit 1
fi

if [ -z "${WORDPRESS_ADMIN_EMAIL}" ]; then
  >&2 echo "WORDPRESS_ADMIN_EMAIL must be set"
  exit 1
fi

if [ -z "${WORDPRESS_URL}" ]; then
  >&2 echo "WORDPRESS_URL must be set"
  exit 1
fi

if [ -z "${WORDPRESS_SITE_TITLE}" ]; then
  >&2 echo "WORDPRESS_SITE_TITLE must be set"
  exit 1
fi

# Best practice settings for running bash scripts:

# Exit the script when an error is encountered
set -o errexit
# Exit the script when a pipe operation fails
set -o pipefail
# Exit the script when there are undeclared variables
set -o nounset
# Uncomment this to see a log to the screen of each command run in the script
# set -o xtrace

export DEBIAN_FRONTEND="noninteractive"
export WORDPRESS_CLI_VERSION="2.4.0"
export WORDPRESS_CLI_MD5="dedd5a662b80cda66e9e25d44c23b25c"
export UPLOAD_MAX_FILESIZE="16M"
export TLS_HOSTNAME="$(echo ${WORDPRESS_URL} | cut -d'/' -f3)"
export NGINX_CONF_DIR="/etc/nginx"
export CERT_DIR="/etc/letsencrypt/live/${TLS_HOSTNAME}"

# Change the hostname to be the same as the WordPress hostname
if [ ! "$(hostname)" == "${TLS_HOSTNAME}" ]; then
  echo "▶ Changing hostname to ${TLS_HOSTNAME}"
  hostnamectl set-hostname "${TLS_HOSTNAME}"
fi

# Add the hostname to /etc/hosts
if [ "$(grep -m1 "${TLS_HOSTNAME}" /etc/hosts)" = "" ]; then
  echo "▶ Adding hostname ${TLS_HOSTNAME} to /etc/hosts so that WordPress can ping itself"
  printf "::1 %s\n127.0.0.1 %s\n" "${TLS_HOSTNAME}" "${TLS_HOSTNAME}" >> /etc/hosts
fi

# Make sure tools needed for install are present
echo "▶ Installing prerequisite tools"
apt-get -qq update
apt-get -qq install -y \
  bc \
  ca-certificates \
  coreutils \
  curl \
  gnupg2 \
  lsb-release

# Install the NGINX Unit repository
if [ ! -f /etc/apt/sources.list.d/unit.list ]; then
  echo "▶ Installing NGINX Unit repository"
  curl -fsSL https://nginx.org/keys/nginx_signing.key | apt-key add -
  echo "deb https://packages.nginx.org/unit/ubuntu/ $(lsb_release -cs) unit" > /etc/apt/sources.list.d/unit.list
fi

# Install the NGINX repository
if [ ! -f /etc/apt/sources.list.d/nginx.list ]; then
  echo "▶ Installing NGINX repository"
  curl -fsSL https://nginx.org/keys/nginx_signing.key | apt-key add -
  echo "deb https://nginx.org/packages/mainline/ubuntu $(lsb_release -cs) nginx" > /etc/apt/sources.list.d/nginx.list
fi

echo "▶ Updating repository metadata"
apt-get -qq update

# WordPress module recommendation: https://make.wordpress.org/hosting/handbook/handbook/server-environment/#php-extensions

# Ubuntu bundles the following PHP extensions with its package distribution:
# date filter hash libxml openssl pcntl pcre Reflection session sodium SPL
# standard zlib

# The php-common package contains the following extensions: exif

# Install PHP with dependencies and NGINX Unit
echo "▶ Installing PHP, NGINX Unit, NGINX, Certbot, and MariaDB"
apt-get -qq install -y --no-install-recommends \
  certbot \
  python3-certbot-nginx \
  php-cli \
  php-common \
  php-bcmath \
  php-curl \
  php-gd \
  php-imagick \
  php-mbstring \
  php-mysql \
  php-opcache \
  php-xml \
  php-zip \
  ghostscript \
  nginx \
  unit \
  unit-php \
  mariadb-server

# Find the major and minor PHP version so that we can write to its conf.d directory
PHP_MAJOR_MINOR_VERSION="$(php -v | head -n1 | cut -d' ' -f2 | cut -d'.' -f1,2)"

if [ ! -f "/etc/php/${PHP_MAJOR_MINOR_VERSION}/embed/conf.d/30-wordpress-overrides.ini" ]; then
  echo "▶ Configuring PHP for use with NGINX Unit and WordPress"
  # Add PHP configuration overrides
  cat > "/etc/php/${PHP_MAJOR_MINOR_VERSION}/embed/conf.d/30-wordpress-overrides.ini" << EOM
; Set a larger maximum upload size so that WordPress can handle
; bigger media files.
upload_max_filesize=${UPLOAD_MAX_FILESIZE}
post_max_size=${UPLOAD_MAX_FILESIZE}
; Write error log to STDERR so that error messages show up in the NGINX Unit log
error_log=/dev/stderr
EOM
fi

# Restart NGINX Unit because we have reconfigured PHP
echo "▶ Restarting NGINX Unit"
service unit restart

# Set up the WordPress database
echo "▶ Configuring MariaDB for WordPress"
mysqladmin create wordpress || echo "Ignoring above error because database may already exist"
mysql -e "GRANT ALL PRIVILEGES ON wordpress.* TO \"wordpress\"@\"localhost\" IDENTIFIED BY \"$WORDPRESS_DB_PASSWORD\"; FLUSH PRIVILEGES;"

if [ ! -f /usr/local/bin/wp ]; then
  # Install the WordPress CLI
  echo "▶ Installing the WordPress CLI tool"
  curl --retry 6 -Ls "https://github.com/wp-cli/wp-cli/releases/download/v${WORDPRESS_CLI_VERSION}/wp-cli-${WORDPRESS_CLI_VERSION}.phar" > /usr/local/bin/wp
  echo "$WORDPRESS_CLI_MD5 /usr/local/bin/wp" | md5sum -c -
  chmod +x /usr/local/bin/wp
fi

if [ ! -d /var/www/wordpress ]; then
  # Create WordPress directories
  mkdir -p /var/www/wordpress
  chown -R www-data:www-data /var/www

  # Download WordPress using the WordPress CLI
  echo "▶ Installing WordPress"
  su -s /bin/sh -c 'wp --path=/var/www/wordpress core download' www-data

  WP_CONFIG_CREATE_CMD="wp --path=/var/www/wordpress config create --extra-php --dbname=wordpress --dbuser=wordpress --dbhost=\"localhost:/var/run/mysqld/mysqld.sock\" --dbpass=\"${WORDPRESS_DB_PASSWORD}\""

  # This snippet is injected into the wp-config.php file when it is created;
  # it informs WordPress that we are behind a reverse proxy and as such
  # allows it to generate links using HTTPS
  cat > /tmp/wp_forwarded_for.php << 'EOM'
/* Turn HTTPS 'on' if HTTP_X_FORWARDED_PROTO matches 'https' */
if (isset($_SERVER['HTTP_X_FORWARDED_PROTO']) && strpos($_SERVER['HTTP_X_FORWARDED_PROTO'], 'https') !== false) {
    $_SERVER['HTTPS'] = 'on';
}

if (isset($_SERVER['HTTP_X_FORWARDED_HOST'])) {
    $_SERVER['HTTP_HOST'] = $_SERVER['HTTP_X_FORWARDED_HOST'];
}
EOM

  # Create WordPress configuration
  su -s /bin/sh -p -c "cat /tmp/wp_forwarded_for.php | ${WP_CONFIG_CREATE_CMD}" www-data
  rm /tmp/wp_forwarded_for.php
  su -s /bin/sh -p -c "wp --path=/var/www/wordpress config set 'FORCE_SSL_ADMIN' 'true'" www-data

  # Install WordPress
  WP_SITE_INSTALL_CMD="wp --path=/var/www/wordpress core install --url=\"${WORDPRESS_URL}\" --title=\"${WORDPRESS_SITE_TITLE}\" --admin_user=\"${WORDPRESS_ADMIN_USER}\" --admin_password=\"${WORDPRESS_ADMIN_PASSWORD}\" --admin_email=\"${WORDPRESS_ADMIN_EMAIL}\" --skip-email"
  su -s /bin/sh -p -c "${WP_SITE_INSTALL_CMD}" www-data

  # Set permalink structure to a sensible default that isn't in the UI
  su -s /bin/sh -p -c "wp --path=/var/www/wordpress option update permalink_structure '/%year%/%monthnum%/%postname%/'" www-data

  # Remove sample file because it is cruft and could be a security problem
  rm /var/www/wordpress/wp-config-sample.php

  # Ensure that WordPress permissions are correct
  find /var/www/wordpress -type d -exec chmod g+s {} \;
  chmod g+w /var/www/wordpress/wp-content
  chmod -R g+w /var/www/wordpress/wp-content/themes
  chmod -R g+w /var/www/wordpress/wp-content/plugins
fi

if [ "${container:-unknown}" != "lxc" ] && [ "$(grep -m1 -a container=lxc /proc/1/environ | tr -d '\0')" == "" ]; then
  NAMESPACES='"namespaces": {
        "cgroup": true,
        "credential": true,
        "mount": true,
        "network": false,
        "pid": true,
        "uname": true
    }'
else
  NAMESPACES='"namespaces": {}'
fi

PHP_MEM_LIMIT="$(grep 'memory_limit' /etc/php/${PHP_MAJOR_MINOR_VERSION}/embed/php.ini | tr -d ' ' | cut -f2 -d= | numfmt --from=iec)"
AVAIL_MEM="$(grep MemAvailable /proc/meminfo | tr -d ' kB' | cut -f2 -d: | numfmt --from-unit=K)"
MAX_PHP_PROCESSES="$(echo "${AVAIL_MEM}/${PHP_MEM_LIMIT}+5" | bc)"
echo "▶ Calculated the maximum number of PHP processes as ${MAX_PHP_PROCESSES}. You may want to tune this value due to variations in your configuration. It is not unusual to see values between 10-100 in production configurations."

echo "▶ Configuring NGINX Unit to use PHP and WordPress"
cat > /tmp/wordpress.json << EOM
{
  "settings": {
    "http": {
      "header_read_timeout": 30,
      "body_read_timeout": 30,
      "send_timeout": 30,
      "idle_timeout": 180,
      "max_body_size": $(numfmt --from=iec ${UPLOAD_MAX_FILESIZE})
    }
  },
  "listeners": {
    "127.0.0.1:8080": {
      "pass": "routes/wordpress"
    }
  },
  "routes": {
    "wordpress": [
      {
        "match": {
          "uri": [
            "*.php",
            "*.php/*",
            "/wp-admin/"
          ]
        },
        "action": {
          "pass": "applications/wordpress/direct"
        }
      },
      {
        "action": {
          "share": "/var/www/wordpress",
          "fallback": {
            "pass": "applications/wordpress/index"
          }
        }
      }
    ]
  },
  "applications": {
    "wordpress": {
      "type": "php",
      "user": "www-data",
      "group": "www-data",
      "processes": {
        "max": ${MAX_PHP_PROCESSES},
        "spare": 1
      },
      "isolation": {
        ${NAMESPACES}
      },
      "targets": {
        "direct": {
          "root": "/var/www/wordpress/"
        },
        "index": {
          "root": "/var/www/wordpress/",
          "script": "index.php"
        }
      }
    }
  }
}
EOM

curl -X PUT --data-binary @/tmp/wordpress.json --unix-socket /run/control.unit.sock http://localhost/config

# Make directory for NGINX cache
mkdir -p /var/cache/nginx/proxy

echo "▶ Configuring NGINX"
cat > ${NGINX_CONF_DIR}/nginx.conf << EOM
user nginx;
worker_processes auto;

error_log  /var/log/nginx/error.log warn;
pid        /var/run/nginx.pid;

events {
    worker_connections  1024;
}

http {
    include       ${NGINX_CONF_DIR}/mime.types;
    default_type  application/octet-stream;

    log_format  main  '\$remote_addr - \$remote_user [\$time_local] "\$request" '
                      '\$status \$body_bytes_sent "\$http_referer" '
                      '"\$http_user_agent" "\$http_x_forwarded_for"';

    access_log  /var/log/nginx/access.log  main;
    sendfile        on;
    client_max_body_size ${UPLOAD_MAX_FILESIZE};
    keepalive_timeout  65;

    # gzip settings
    include ${NGINX_CONF_DIR}/gzip_compression.conf;

    # Cache settings
    proxy_cache_path /var/cache/nginx/proxy
        levels=1:2
        keys_zone=wp_cache:10m
        max_size=10g
        inactive=60m
        use_temp_path=off;

    include ${NGINX_CONF_DIR}/conf.d/*.conf;
}
EOM

cat > ${NGINX_CONF_DIR}/gzip_compression.conf << 'EOM'
# Credit: https://github.com/h5bp/server-configs-nginx/

# ----------------------------------------------------------------------
# | Compression                                                        |
# ----------------------------------------------------------------------

# https://nginx.org/en/docs/http/ngx_http_gzip_module.html

# Enable gzip compression.
# Default: off
gzip on;

# Compression level (1-9).
# 5 is a perfect compromise between size and CPU usage, offering about 75%
# reduction for most ASCII files (almost identical to level 9).
# Default: 1
gzip_comp_level 6;

# Don't compress anything that's already small and unlikely to shrink much if at
# all (the default is 20 bytes, which is bad as that usually leads to larger
# files after gzipping).
# Default: 20
gzip_min_length 256;

# Compress data even for clients that are connecting to us via proxies,
# identified by the "Via" header (required for CloudFront).
# Default: off
gzip_proxied any;

# Tell proxies to cache both the gzipped and regular version of a resource
# whenever the client's Accept-Encoding capabilities header varies;
# Avoids the issue where a non-gzip capable client (which is extremely rare
# today) would display gibberish if their proxy gave them the gzipped version.
# Default: off
gzip_vary on;

# Compress all output labeled with one of the following MIME-types.
# `text/html` is always compressed by gzip module.
# Default: text/html
gzip_types
  application/atom+xml
  application/geo+json
  application/javascript
  application/x-javascript
  application/json
  application/ld+json
  application/manifest+json
  application/rdf+xml
  application/rss+xml
  application/vnd.ms-fontobject
  application/wasm
  application/x-web-app-manifest+json
  application/xhtml+xml
  application/xml
  font/eot
  font/otf
  font/ttf
  image/bmp
  image/svg+xml
  text/cache-manifest
  text/calendar
  text/css
  text/javascript
  text/markdown
  text/plain
  text/xml
  text/vcard
  text/vnd.rim.location.xloc
  text/vtt
  text/x-component
  text/x-cross-domain-policy;
EOM

cat > ${NGINX_CONF_DIR}/conf.d/default.conf << EOM
upstream unit_php_upstream {
    server 127.0.0.1:8080;

    keepalive 32;
}

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

    # ACME-challenge used by Certbot for Let's Encrypt
    location ^~ /.well-known/acme-challenge/ {
      root /var/www/certbot;
    }

    location / {
      return 301 https://${TLS_HOSTNAME}\$request_uri;
    }
}

server {
    listen      443 ssl http2;
    listen [::]:443 ssl http2;
    server_name ${TLS_HOSTNAME};
    root        /var/www/wordpress/;

    # Let's Encrypt configuration
    ssl_certificate         ${CERT_DIR}/fullchain.pem;
    ssl_certificate_key     ${CERT_DIR}/privkey.pem;
    ssl_trusted_certificate ${CERT_DIR}/chain.pem;

    include ${NGINX_CONF_DIR}/options-ssl-nginx.conf;
    ssl_dhparam ${NGINX_CONF_DIR}/ssl-dhparams.pem;

    # OCSP stapling
    ssl_stapling on;
    ssl_stapling_verify on;

    # Proxy caching
    proxy_cache wp_cache;
    proxy_cache_valid 200 302 1h;
    proxy_cache_valid 404 1m;
    proxy_cache_revalidate on;
    proxy_cache_background_update on;
    proxy_cache_lock on;
    proxy_cache_use_stale error timeout http_500 http_502 http_503 http_504;

    location = /favicon.ico {
        log_not_found off;
        access_log off;
    }

    location = /robots.txt {
        allow all;
        log_not_found off;
        access_log off;
    }
    
    # Deny all attempts to access hidden files such as .htaccess, .htpasswd, 
    # .DS_Store (Mac)
    # Keep logging the requests to parse later (or to pass to firewall utilities 
    # such as fail2ban)
    location ~ /\. {
        deny all;
    }

    # Deny access to any files with a .php extension in the uploads directory;
    # works in subdirectory installs and also in multi-site network.
    # Keep logging the requests to parse later (or to pass to firewall utilities 
    # such as fail2ban).
    location ~* /(?:uploads|files)/.*\.php\$ {
        deny all;
    }

    # WordPress: deny access to wp-content, wp-includes PHP files
    location ~* ^/(?:wp-content|wp-includes)/.*\.php\$ {
        deny all;
    }

    # Deny public access to wp-config.php
    location ~* wp-config.php {
        deny all;
    }

    # Do not log access for static assets, media
    location ~* \.(?:css(\.map)?|js(\.map)?|jpe?g|png|gif|ico|cur|heic|webp|tiff?|mp3|m4a|aac|ogg|midi?|wav|mp4|mov|webm|mpe?g|avi|ogv|flv|wmv)$ {
        access_log off;
    }

    location ~* \.(?:svgz?|ttf|ttc|otf|eot|woff2?)$ {
        add_header Access-Control-Allow-Origin "*";
        access_log off;
    }

    location / {
        try_files \$uri @index_php;
    }

    location @index_php {
        proxy_socket_keepalive on;
        proxy_http_version 1.1;
        proxy_set_header Connection "";
        proxy_set_header X-Real-IP \$remote_addr;
        proxy_set_header X-Forwarded-For \$proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto \$scheme;
        proxy_set_header Host \$host;

        proxy_pass       http://unit_php_upstream;
    }

    location ~* \.php\$ {
        proxy_socket_keepalive on;
        proxy_http_version 1.1;
        proxy_set_header Connection "";
        proxy_set_header X-Real-IP \$remote_addr;
        proxy_set_header X-Forwarded-For \$proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto \$scheme;
        proxy_set_header Host \$host;

        try_files        \$uri =404;
        proxy_pass       http://unit_php_upstream;
    }
}
EOM

echo "▶ Stopping NGINX in order to set up Let's Encrypt"
service nginx stop

mkdir -p /var/www/certbot
chown www-data:www-data /var/www/certbot
chmod g+s /var/www/certbot

if [ ! -f ${NGINX_CONF_DIR}/options-ssl-nginx.conf ]; then
  echo "▶ Downloading recommended TLS parameters"
  curl --retry 6 -Ls -z "Tue, 14 Apr 2020 16:36:07 GMT" \
    -o "${NGINX_CONF_DIR}/options-ssl-nginx.conf" \
    "https://raw.githubusercontent.com/certbot/certbot/master/certbot-nginx/certbot_nginx/_internal/tls_configs/options-ssl-nginx.conf" \
    || echo "Couldn't download latest options-ssl-nginx.conf"
fi

if [ ! -f ${NGINX_CONF_DIR}/ssl-dhparams.pem ]; then
  echo "▶ Downloading recommended TLS DH parameters"
  curl --retry 6 -Ls -z "Tue, 14 Apr 2020 16:49:18 GMT" \
    -o "${NGINX_CONF_DIR}/ssl-dhparams.pem" \
    "https://raw.githubusercontent.com/certbot/certbot/master/certbot/certbot/ssl-dhparams.pem" \
    || echo "Couldn't download latest ssl-dhparams.pem"
fi

# If tls_certs_init.sh hasn't been run before, remove the self-signed certs
if [ ! -d "/etc/letsencrypt/accounts" ]; then
  echo "▶ Removing self-signed certificates"
  rm -rf "${CERT_DIR}"
fi

if [ "" = "${LETS_ENCRYPT_STAGING:-}" ] || [ "0" = "${LETS_ENCRYPT_STAGING}" ]; then
  CERTBOT_STAGING_FLAG=""
else
  CERTBOT_STAGING_FLAG="--staging"
fi

if [ ! -f "${CERT_DIR}/fullchain.pem" ]; then
  echo "▶ Generating certificates with Let's Encrypt"
  certbot certonly --standalone \
         -m "${WORDPRESS_ADMIN_EMAIL}" \
         ${CERTBOT_STAGING_FLAG} \
         --agree-tos --force-renewal --non-interactive \
         -d "${TLS_HOSTNAME}"
fi

echo "▶ Starting NGINX to use new configuration and enabling NGINX Unit service"
service nginx start
systemctl enable unit.service

# Periodic Let's Encrypt cert renewal
if [ ! -f "/etc/systemd/system/certbot-renewal.timer" ]; then
  echo "▶ Adding systemd Certbot renewal service timer"
  cat > /etc/systemd/system/certbot-renewal.timer << EOM
[Unit]
Description=Timer for Certbot Renewal

[Timer]
OnBootSec=300
OnUnitActiveSec=1w

[Install]
WantedBy=multi-user.target
EOM
fi

echo "▶ Enabling Let's Encrypt auto-renewal"
systemctl start certbot-renewal.timer
systemctl enable certbot-renewal.timer

Hi @c0nsaw, currently the NGINX repository does not have packages for Ubuntu 22.04.

ah..., thank you sir :)

I got a redirect error when using this script.
The server tries to redirect to an empty URL: https:///

After running this script with my domain name on my VPS server (properly redirected), I can access https://www.mydomain.com/wp-admin, but not https://www.mydomain.com/ . curl -v https://www.mydomain.lt returns:
* Trying x.x.x.x:443...
* Connected to www.mydomain.lt (x.x.x.x) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* CAfile: /etc/ssl/certs/ca-certificates.crt
* CApath: /etc/ssl/certs
* TLSv1.0 (OUT), TLS header, Certificate Status (22):
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
* TLSv1.2 (IN), TLS header, Certificate Status (22):
* TLSv1.3 (IN), TLS handshake, Server hello (2):
* TLSv1.2 (IN), TLS header, Finished (20):
* TLSv1.2 (IN), TLS header, Supplemental data (23):
* TLSv1.3 (IN), TLS handshake, Encrypted Extensions (8):
* TLSv1.2 (IN), TLS header, Supplemental data (23):
* TLSv1.3 (IN), TLS handshake, Certificate (11):
* TLSv1.2 (IN), TLS header, Supplemental data (23):
* TLSv1.3 (IN), TLS handshake, CERT verify (15):
* TLSv1.2 (IN), TLS header, Supplemental data (23):
* TLSv1.3 (IN), TLS handshake, Finished (20):
* TLSv1.2 (OUT), TLS header, Finished (20):
* TLSv1.3 (OUT), TLS change cipher, Change cipher spec (1):
* TLSv1.2 (OUT), TLS header, Supplemental data (23):
* TLSv1.3 (OUT), TLS handshake, Finished (20):
* SSL connection using TLSv1.3 / TLS_AES_256_GCM_SHA384
* ALPN, server accepted to use h2
* Server certificate:
* subject: CN=www.vesia.lt
* start date: Nov 9 18:36:06 2022 GMT
* expire date: Feb 7 18:36:05 2023 GMT
* subjectAltName: host "www.vesia.lt" matched cert's "www.vesia.lt"
* issuer: C=US; O=Let's Encrypt; CN=R3
* SSL certificate verify ok.
* Using HTTP2, server supports multiplexing
* Connection state changed (HTTP/2 confirmed)
* Copying HTTP/2 data in stream buffer to connection buffer after upgrade: len=0
* TLSv1.2 (OUT), TLS header, Supplemental data (23):
* TLSv1.2 (OUT), TLS header, Supplemental data (23):
* TLSv1.2 (OUT), TLS header, Supplemental data (23):
* Using Stream ID: 1 (easy handle 0x56080311be80)
* TLSv1.2 (OUT), TLS header, Supplemental data (23):
> GET / HTTP/2
> Host: www.vesia.lt
> user-agent: curl/7.81.0
> accept: */*
>
* TLSv1.2 (IN), TLS header, Supplemental data (23):
* TLSv1.3 (IN), TLS handshake, Newsession Ticket (4):
* TLSv1.2 (IN), TLS header, Supplemental data (23):
* TLSv1.3 (IN), TLS handshake, Newsession Ticket (4):
* old SSL session ID is stale, removing
* TLSv1.2 (IN), TLS header, Supplemental data (23):
* Connection state changed (MAX_CONCURRENT_STREAMS == 128)!
* TLSv1.2 (OUT), TLS header, Supplemental data (23):
* TLSv1.2 (IN), TLS header, Supplemental data (23):
* TLSv1.2 (IN), TLS header, Supplemental data (23):
< HTTP/2 301
< server: nginx/1.23.2
< date: Wed, 09 Nov 2022 21:39:33 GMT
< content-length: 0
< location: //
<
* Connection #0 to host www.mydomain.lt left intact

May it be that something is wrong with nginx config?

On the other VPS server and domain with the same OS (Ubuntu 20.04) this setup runs till the day without problem.
Both VPS servers has in their /var/log/nginx/error.log:
2022/11/09 22:39:14 [warn] 1778#1778: no resolver defined to resolve r3.o.lencr.org while requesting certificate status, responder: r3.o.lencr.org, certificate: "/etc/letsencrypt/live/www.mydomain.lt/fullchain.pem"

For a discussion of these files, see Automating Installation of WordPress with NGINX Unit on Ubuntu

I modified this code to work with Debian 12

# Install the NGINX Unit repository
if [ ! -f /etc/apt/sources.list.d/unit.list ]; then
  echo "? Installing NGINX Unit repository"
  curl --output /usr/share/keyrings/nginx-keyring.gpg  https://unit.nginx.org/keys/nginx-keyring.gpg
  echo "deb [signed-by=/usr/share/keyrings/nginx-keyring.gpg] https://packages.nginx.org/unit/debian/ bookworm unit \
          deb-src [signed-by=/usr/share/keyrings/nginx-keyring.gpg] https://packages.nginx.org/unit/debian/ bookworm unit" > /etc/apt/sources.list.d/unit.list
fi

# Install the NGINX repository
if [ ! -f /etc/apt/sources.list.d/nginx.list ]; then
  echo "? Installing NGINX repository"
curl https://nginx.org/keys/nginx_signing.key | gpg --dearmor \
    |  tee /usr/share/keyrings/nginx-archive-keyring.gpg >/dev/null
 echo "deb [signed-by=/usr/share/keyrings/nginx-archive-keyring.gpg] \
http://nginx.org/packages/debian `lsb_release -cs` nginx" \
    |  tee /etc/apt/sources.list.d/nginx.list
fi

everything seems to install fine except for the final step Enabling Let's Encrypt auto-renewal

certbot-renewal.timer: Refusing to start, unit certbot-renewal.service to trigger not loaded.
 Failed to start certbot-renewal.timer - Timer for Certbot Renewal.

░░ Subject: A start job for unit certbot-renewal.timer has failed
░░ Defined-By: systemd
░░ Support: https://www.debian.org/support
░░
░░ A start job for unit certbot-renewal.timer has finished with a failure.
░░
░░ The job identifier is 618 and the job result is failed.

Also, my domain that I used in WORDPRESS_URL triggers a 502 Bad Gateway status

should I be doing anything in nginx to get this fixed?

error log

2024/05/29 07:56:42 [error] 548#548: *13 connect() failed (111: Connection refused) while connecting to upstream, client: 192.87.274.38, server: something.org, request: "GET / HTTP/1.1", upstream: "http://127.0.0.1:8080/", host: "something.org"

port 8080 is not open anywhere, should that port be listening?

lsof -nP -iTCP -sTCP:LISTEN
COMMAND   PID  USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
sshd      582  root    3u  IPv4   2461      0t0  TCP *:22 (LISTEN)
sshd      582  root    4u  IPv6   2472      0t0  TCP *:22 (LISTEN)
mariadbd  583 mysql   22u  IPv4   2486      0t0  TCP 127.0.0.1:3306 (LISTEN)
nginx     815  root    6u  IPv4  18377      0t0  TCP *:80 (LISTEN)
nginx     815  root    7u  IPv6  18378      0t0  TCP *:80 (LISTEN)
nginx     815  root    8u  IPv4  18379      0t0  TCP *:443 (LISTEN)
nginx     815  root    9u  IPv6  18380      0t0  TCP *:443 (LISTEN)
nginx     816 nginx    6u  IPv4  18377      0t0  TCP *:80 (LISTEN)
nginx     816 nginx    7u  IPv6  18378      0t0  TCP *:80 (LISTEN)
nginx     816 nginx    8u  IPv4  18379      0t0  TCP *:443 (LISTEN)
nginx     816 nginx    9u  IPv6  18380      0t0  TCP *:443 (LISTEN)
nginx     817 nginx    6u  IPv4  18377      0t0  TCP *:80 (LISTEN)
nginx     817 nginx    7u  IPv6  18378      0t0  TCP *:80 (LISTEN)
nginx     817 nginx    8u  IPv4  18379      0t0  TCP *:443 (LISTEN)
nginx     817 nginx    9u  IPv6  18380      0t0  TCP *:443 (LISTEN)
nginx     818 nginx    6u  IPv4  18377      0t0  TCP *:80 (LISTEN)
nginx     818 nginx    7u  IPv6  18378      0t0  TCP *:80 (LISTEN)
nginx     818 nginx    8u  IPv4  18379      0t0  TCP *:443 (LISTEN)
nginx     818 nginx    9u  IPv6  18380      0t0  TCP *:443 (LISTEN)
nginx     819 nginx    6u  IPv4  18377      0t0  TCP *:80 (LISTEN)
nginx     819 nginx    7u  IPv6  18378      0t0  TCP *:80 (LISTEN)
nginx     819 nginx    8u  IPv4  18379      0t0  TCP *:443 (LISTEN)
nginx     819 nginx    9u  IPv6  18380      0t0  TCP *:443 (LISTEN)
nginx     820 nginx    6u  IPv4  18377      0t0  TCP *:80 (LISTEN)
nginx     820 nginx    7u  IPv6  18378      0t0  TCP *:80 (LISTEN)
nginx     820 nginx    8u  IPv4  18379      0t0  TCP *:443 (LISTEN)
nginx     820 nginx    9u  IPv6  18380      0t0  TCP *:443 (LISTEN)
nginx     821 nginx    6u  IPv4  18377      0t0  TCP *:80 (LISTEN)
nginx     821 nginx    7u  IPv6  18378      0t0  TCP *:80 (LISTEN)
nginx     821 nginx    8u  IPv4  18379      0t0  TCP *:443 (LISTEN)
nginx     821 nginx    9u  IPv6  18380      0t0  TCP *:443 (LISTEN)
unitd    1064  unit   14u  IPv4  22156      0t0  TCP *:8300 (LISTEN)

port 8080 is not open anywhere, should that port be listening?

Yes. If you are running Unit having following conf:

...
"listeners": {
    "127.0.0.1:8080": {
      "pass": "routes/wordpress"
    }
 }
...

then port 8080 should be listening:

% lsof -nP -iTCP -sTCP:LISTEN
COMMAND    PID USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
unitd   257625  xim   31u  IPv4 959979      0t0  TCP *:8080 (LISTEN)

I had to run the unit configurations again (curl -X PUT --data-binary @wordpress.json --unix-socket /var/run/control.unit.sock http://localhost/config)

now I'm getting a new error ERR_INVALID_REDIRECT

curl -I https://something.org/
HTTP/2 301
server: nginx/1.26.0
date: Wed, 29 May 2024 17:33:58 GMT
content-length: 0
location: //

the /wp-login.php works,
but I was hit with a (413 Content Too Large) error when trying to login,
I removed "max_body_size" from wordpress.json and "client_max_body_size " from nginx.conf

still not able to load the front page, must be some nginx misconfiguration in default.conf

visiting a blog post I am getting the error x-unknown-content-type ns_error_redirect_loop

nginx: [emerg] "upstream" directive is not allowed here in /etc/nginx/conf.d/default.conf:1

@wp-coin the article is 4 years old now. What is the end goal you want to achieve? My thinking is there might be an easier way to get there than debug a script that uses and assumes the state of things as of 2020