In the last several years I keep hearing the term multi-tenancy being thrown around, and each time I Google its meaning it leaves me confused:
(Wikipedia) : The term "software multitenancy" refers to a software architecture in which a single instance of software runs on a server and serves multiple tenants. A tenant is a group of users who share a common access with specific privileges to the software instance.
Right. But isn't that already what a server is?!? Software serving multiple clients?!? If I have a VM (or physical server) and start running a web server (httpd, Tomcat, etc.), and that web server starts serving requests for multiple HTTP clients, wouldn't that be a multi-tenant web server? And if I stand up a MySQL database, and that DB starts serving requests for multiple clients, wouldn't that be a multi-tenant DB?!?
I guess I don't see the need to distinguish any server as being multi-tenant...isn't that what servers are already meant to do (serve multiple clients)?
So I ask: if multi-tenancy is "[an] architecture in which a single instance of software runs on a server and serves multiple tenants"...then what is its alternative?
Or, put differently, how could a server (web server, DB, etc.) not be multi-tenant?!?