You need php 5.4 or higher. I’m developing under a debian 8.5 which uses 5.6.23.
MySQL is at version 5.5.x but there is nothing special used. Here it is running using MariaDB 10.0.25 which works even faster.
Apache 2.2 or higher. You will need the headers and expires modules. And enable ssl.
My own logging server is running using a small VPS with one virtual core and 4GB RAM as its only purpose. Currently 8 servers are constantly logging to it with a minimal load and an average of 2 inserts into mysql per second.
The web gui lggr uses some 3rd party libraries like jquery or bootstrap. These packages are not included in the git sources but referenced to from the main config class.
You can either use the external urls written there or you might want to package all dependencies into your local lggr installation lggr_contrib.tar, which might be more stable and adds to your privacy.
The tools and packages used are: