Custom logging help

Morning all, I am running on Ubuntu 20.04 and going to have multiple servers and wanted to have a central place for logs. I have a shared mount point on the servers, and reading here and trying to figure this out. I can get the local instance from a file that is created on boot;
cat /var/lib/cloud/data/instance-id OR even the private IP and prefix that name;

So I see the logback.xml file and it does seem to have variables such as this;

So, I really want to just see what variables are supported and/or how to add something unique the machine as a prefix. Figuring it was apache, I tried changing the pattern to;

/mnt/hive_logs/%A.event.log. and on restart I did have a new log in the shared folder, but the name was %A.event.log, so I could really use (in order of preference);

local instance name+event.log

I could do things local, and rotate on the hour and rename, move but for debug/troubleshooting, it’s just the wrong approach, so basically what variables are supported and/or how to get something into that XML that is a bit smarter and unique.

I think you could use something like this:

user@Dominics-MBP bin % grep event.log ../conf/logback.xml 

this would generate something like that:

-rw-r--r--   1 user  staff       0 Feb 25 15:10 Dominics-MBP.local-event.log