You are migrating an existing solution to Azure.
The solution includes a user interface tier and a database tier. The user interface tier runs on multiple virtual machines (VMs). The user interface tier has a website that uses Node.js.
The user interface tier has a background process that uses Python. This background process runs as a scheduled job. The user interface tier is updated frequently. The database tier uses a self-hosted MySQL database. The user interface tier requires up to 25 CPU cores.
You must be able to revert the user interface tier to a previous version if updates to the website cause technical problems. The database requires up to 50 GB of memory. The database must run in a single VM.
You need to deploy the solution to Azure. What should you do first?