Can Juju be used on a single server to make it easier to deploy services like MySQL and any other Charms that are available? I understand that it is a tool to deploy and manage huge cloud servers but can it just as well be used on a single server to utilize the simplicity of charms?
Juju can (from version 1.18) deploy to any Ubuntu Server with OpenSSH via manual provisioning:
The basic process is you register your machine(s) with Juju via:
juju add-machine ssh:10.1.1.2 for example. And then you can deploy services to those machines.
For larger deployments you can use Juju together with the default multiple-server-install coordinator (called MAAS) to deploy charms onto physical machines, or extra physical units to existing services. Juju with MAAS lets you treat a group of physical machines as a cloud, essentially.
Local (Container) deployments
You can also run charms directly on your workstation, which we call a local environment. You run each separate service unit as different LXC container on a single machine (Ubuntu only).