Infra with some machines server
https://www.traccar.org/horizontal-scaling/
But if scale is not the main thing, you should not have to make your life miserable. There is more simple approach.
Can I work with horizontal scaling, but I need container right?
You don't need any containers to use horizontal scaling.
Just build modern app, set it for server directory and use single instance of Traccar.
https://www.traccar.org/secure-connection/
Just add more virtual hosts
But there is the tricky moment with notification which includes url for position, event, etc
Right, I read the documentation about horizontal scaling, What can I read more to implement it?
Can I run this infra?
Machine 1 - Mysql database.
Machine 2 - Server + Modern UI - Domain www.machine2.com - Database machine 1
Machine 3 - Server + Modern UI (2) - Domain www.machine3.com - Database machine 1
Machine 4 - Server + Modern UI (3) - Domain www.machine4.com - Database machine 1
With a NgixProxyManger or Treafik I check request and redirect to Machine.
I'd like some servers/ui's (with different logo/configs) in same database.