The event severity object indicates the severity level of
this notification. The severity levels are:
'informational': The notification contains important health
or operational state information that is
valuable to an administrator, however, the
event itself does not indicate a failure or
impairment condition.
'warning': The notification contains serious health or
operational state information that could be
a precursor to system impairment or
eventual failure.
'error': The notification contains critical health
or operational state information and
indicates that the system has experienced
an impairment and/or a functional failure.