i've read here:
Wordpress Installation on Two Servers - Loadbalancing
and here:
https://www.quora.com/How-do-I-load-balance-on-WordPress-with-2-LAP-web-servers-and-1-Mysql-DB
none of the links addresses the following issue:
You go to server1, press "install plugin foobar" now server1 downloads files for plugin foobar. It makes DB changes for plugin foobar. But on server2, foobar files are not available. I cannot even make sure to be accessing server2 from the web as I get randomly dropped on server1 or server2.
Another problem: Plugin updates.
I go to server1 and press "update" on plugin foobar v1.0. It gets updated on server1 to v9.0. The plugin update, performs db changes as well. On server2 we still have the files from v1.0. Not good. Even if I manage to access server2, won't it be in a faulty state? that is: db from v9.0 and files from v1.0. The Plugin update might eventually not even work with this state, so it could be that I cannot update well foobar v1.0 to v9.0 on server2 once i reached the server.