Understanding Events

An
Event
is a data object type that contains information about state changes of managed entities and other objects on the server. Events include user actions and system actions that occur on datacenters, datastores, clusters, hosts, resource pools, virtual machines, networks, and distributed virtual switches. For example, these common system activities generate one or more
Event
data objects:
  • Powering a virtual machine on or off
  • Creating a virtual machine
  • Installing VMware Tools on the guest OS of a virtual machine
  • Reconfiguring a compute resource
  • Adding a newly configured ESXi system to a vCenter Server system
In the vSphere Client, information from
Event
objects generated on a standalone ESXi hosts displays in the Events tab. For managed hosts, information from
Event
objects displays in the Tasks & Events tab.
Persistence of
Event
objects depends on the system setup.
  • Standalone ESXi hosts –
    Event
    objects are not persistent. Events are retained only for as long as the host system’s local memory can contain them. Rebooting a standalone ESXi host or powering off a virtual machine removes
    Event
    objects from local memory.
    A standalone ESXi host might keep about 15 minutes worth of
    Event
    data, but this can vary depending on the processing load of the host, the number of virtual machines, and other factors.
  • Managed ESXi systems.
    Event
    objects are persistent. Managed ESXi systems send
    Event
    data to the vCenter Server system that manages them, and the vCenter Server system stores the information its database.
You can use the event sample applications included in the SDK package with either managed or standalone ESXi systems and with vCenter Server systems.
Using an
EventHistoryCollector
, you can obtain information about these objects as they are being collected on a specific ESXi system, or from a specific historical period from the database. See Using an EventHistoryCollector.