1. A method comprising: maintaining, by a processor executing a host controller, a hierarchy of labels in a management data store, each of the labels of the hierarchy of labels representing a distinct virtual machine (VM) parameter that describes a characteristic of a VM and is separate from a unique identifier (ID) of the VM, wherein the management data store maintaining the hierarchy of labels is separate from VMs associated with the labels; detecting, by the processor, without user interaction, an event that triggers a label reassignment for a VM of a plurality of VMs hosted by one or more servers coupled to the host controller; identifying, by the processor in response to detecting the event, one or more labels of the hierarchy of labels that correspond to the event and the VM for the label reassignment, the identifying comprising: providing a user interface presenting the hierarchy of labels; receiving a selection of a set of labels for the VM from the hierarchy of labels; and assigning, in response to the selection, the set of labels from the hierarchy of labels to the VM; storing, by the processor in response to identifying the one or more labels, identifiers of the identified labels with the unique ID of the VM in a VM data store, the storing further comprising: storing, in a first database table of the management store, the identifiers of the identified labels from the hierarchy, descriptions of the identified labels, and relationships between the identified labels, wherein the first database table comprises the hierarchy of labels and is a tree having a plurality of nodes representing the labels and a plurality of edges representing relationships between the labels; and storing, in a second database table of the management store, the unique ID of the VM along with the identifiers of the identified labels corresponding to the VM by at least one of modifying previously-assigned labels of the VM or adding new labels to the VM; grouping, by the processor in response to the label reassignment for the VM, and in view of the relationships between the identified labels, the VM with other VMs associated with the identified labels; and performing, by the processor in view of the grouping, a management operation on the VM and the other VMs in response to receiving an end user selection of the identified labels and an identification of the management operation via a graphical user interface (GUI).