actually kubernetes also works for the small scale. if you have more than 1 server you either need one of the following or combine it:

- automation - configuration management - scheduling - load balancing - provisioning

you can than either built it yourself, probably with the help of ansible/puppet,... or you can just use kubespray+k8s or any other "managed" k8s thingy.

of course if you try to manage more than 1 server you at least need some understanding of networking (but probably not that deep than you think), understanding of namepsaces or virtualisation (unless you think it's a good idea to run 1000 tools on one host without at least limit their cpu/memory/io usage) and you probably need knowledge of linux and also at least a little bit of knowing how distributed leader election might work. But no matter what, if you run more than one system you need to have somebody that is capable of that.