# Hosts / Servers

This concept is mostly tailored to users of VM Essentials who are responsible for managing and maintaining the underlying infrastructure integrations. A Host typically refers to a Docker Host in which a container (within an Instance) is running, or a hypervisor that virtual machines can be provisioned onto. A server is the underlying general representation of a physical or virtual server. It could be a Host representation, a Virtual Machine, or even a Bare Metal delineation.

When a user provisions a VM-based Instance, a corresponding server record is created to represent the link to the actual resource via the underlying provisioning engine. This may seem a bit odd but provides an aspect of VM Essentials that is quite powerful. This singular concept is what allows VM Essentials to ingest “brownfield” environments. We do not need to start clean. VM Essentials can be integrated into existing environments and manage existing virtual machines. The way VM Essentials does this is by periodically syncing existing VMs from the added cloud integrations. A server record will be created and periodically updated (every five minutes, by default) with realtime information and changes. This, in essence, provides CMDB-like capabilities as well. When a server is discovered, the user (given the appropriate access) can convert the virtual machine to a managed Instance. When this is done, a corresponding Instance is made in the provisioning section of VM Essentials and the VM Essentials Agent can optionally be installed to provide more refined guest operating system-level statistics and logging.
