I followed the link on https://www.bookstackapp.com/docs/admin/installation/ which led me here.

here are the steps i followed

1. Create an empty directory and cd into it
2. Create empty directories for the volumes mkdir bookstack_db_data and mkdir bookstack_app_data
3. Create the file docker-compose.yml as linked above
4. Paste in the file contents as linked above. Change only row 37 APP_KEY with the output from the command docker run -it --rm --entrypoint /bin/bash lscr.io/linuxserver/bookstack:latest appkey
5. Run docker-compose up -d

resulting error (logs from bookstack container)

  SQLSTATE[HY000] [2002] Operation timed out (Connection: mysql, SQL: select exists (select 1 from information_schema.tables where table_schema = 'bookstack' and table_name = 'migrations' and table_type in ('BASE TABLE', 'SYSTEM VERSIONED')) as `exists`)
  at /app/www/vendor/laravel/framework/src/Illuminate/Database/Connection.php:825
    821▕                     $this->getName(), $query, $this->prepareBindings($bindings), $e
    822▕                 );
    823▕             }
    824▕ 
  ➜ 825▕             throw new QueryException(
    826▕                 $this->getName(), $query, $this->prepareBindings($bindings), $e
    827▕             );
    828▕         }
    829▕     }
      +38 vendor frames 
  39  /app/www/artisan:35
      Illuminate\Foundation\Console\Kernel::handle()

No visible errors from mariadb.

Not sure if i'm missing anything but I would expect the example to work as-is.
using synology dsm fwiw

I'll therefore close this off since re-running the script worked okay, but I'll keep this in mind if I get further reports, or if there's specific errors to address.

I also had issues with DOMAIN=$1 which also caused it to error out. I cannot remember what the error was though.

Also, if you still have it, please share the install log from the original failed attempt (Should be in the same directory as where you originally ran the script from).

I don't think changes in Ubuntu should need those changes, but there could environmental elements which lead to differences, so it would be good to know those to properly plan for them in future.

Changed these sections
#Get the domain from the arguments (Requested later if not set)
if [ -z "${1-}" ]; then
read -rp "Enter your domain (or press Enter to use IP $CURRENT_IP): " DOMAIN
DOMAIN=${DOMAIN:-$CURRENT_IP}
else
DOMAIN=$1
fi

#Install core system packages
function run_package_installs() {
apt update
apt install -y git unzip apache2 curl mysql-server php8.3
php8.3-fpm php8.3-curl php8.3-mbstring php8.3-ldap php8.3-xml php8.3-zip php8.3-gd php8.3-mysql
}

#Set up database
function run_database_setup() {
#Ensure database service has started
systemctl start mysql.service
systemctl enable mysql.service
sleep 3

Todo

• Fix mysql commands to suit mariadb (User create command)
• Swap out composer install/usage to system cli download-vendor command