At the following link I found a project very similar to the one I would like to do. The only difference is the database. I use PostgreSQL and not MySQL, moreover I don't access the database from the outside but I install pdAdmin on the server that I use to backup and restore all records.
I noticed that in the .yaml file there is also the Traefik load balancer. I don't use this service on my file. I would like to know if it is mandatory to use a load balancer or, for the moment, I can forget about it.
It seems to me that it is desirable to use a load balancer but not mandatory but I no longer know what to think and what attempts to do so I preferred to ask.
If you have multiple services on one machine each running on separate ports you don't need a proxy like Traefik, but you'll have to open those ports to the outside and specify the port number when you want to connect to that service. You can use Traefik to route based on host names instead of ports or to load balance between multiple copies of a service or to perform additional actions such as authentication, caching, filtering, etc. (see Middleware for those kinds of things). Traefik will then be the only application exposed and you have one place to manage those actions.