Hello, @justcoolk
You should be able to run that on a Ubuntu 20.04 / 18.04 droplet.
To install MSSQL (mssql-server) follow these steps here:
- Import the public repository GPG keys:
wget -qO- https://packages.microsoft.com/keys/microsoft.asc | sudo apt-key add -
Register the Microsoft SQL Server Ubuntu repository for SQL Server 2019:
sudo add-apt-repository "$(wget -qO- https://packages.microsoft.com/config/ubuntu/18.04/mssql-server-2019.list)"
- Run the following commands to install SQL Server:
sudo apt-get update
sudo apt-get install -y mssql-server
- After the package installation finishes, run mssql-conf setup and follow the prompts to set the SA password and choose your edition.
sudo /opt/mssql/bin/mssql-conf setup
Make sure to specify a strong password for the SA account (Minimum length 8 characters, including uppercase and lowercase letters, base 10 digits and/or non-alphanumeric symbols).
- Once the configuration is done, verify that the service is running:
systemctl status mssql-server --no-pager
If you plan to connect remotely, you might also need to open the SQL Server TCP port (default 1433) on your firewall.
Source: official Microsoft documentation
Regarding the .NET core install, you could follow step one form this article here:
https://www.digitalocean.com/community/tutorials/how-to-deploy-an-asp-net-core-application-with-mysql-server-using-nginx-on-ubuntu-18-04
Hope that this helps!
Regards,
Alex

by Oluyemi Olususi
ASP.NET Core is a more modular version of Microsoft’s ASP.NET Framework. It's a high-performant, open-source framework for building modern web applications. In this tutorial you'll set up and deploy a production-ready ASP.NET Core application with a MySQL Server on Ubuntu 18.04 using Nginx.