I was proudly wearing one of my Salt Stack shirts the other day when my daughter asked me, "What is Salt Stack?" I began by explaining the problem it solved. If you have multiple servers and want to do things to those servers, you would need to log in to each one and do those things one at a time on each one. They could be fairly simple tasks like restarting them or checking how long they have been running. Or, you might want to do more complicated things like installing software and then configuring that software based upon your own specific criteria. You also might want to add users and configure permissions for them.