title: VMware vCenter Server Appliance: Time Synchronization
agents: vcsa_health
catalog: app/vmware
license: GPL-2.0-only
distribution: check_mk
description:
 This check monitors the time synchronization configuration of a VMware
 vCenter Server Appliance (VCSA): the synchronization mode (NTP or host
 time) and, when NTP is used, the reachability of the configured NTP
 servers. The data is retrieved by the special agent {agent_vcsa_health}.

 Accurate time is required for single sign-on token validation and
 certificate checks, so drift on the appliance causes widespread and
 confusing authentication failures.

 The service also reports the measured clock drift between the appliance
 and the Checkmk server, along with the appliance's own date, time and
 timezone. Drift is compared as a magnitude, so an appliance running fast
 is treated the same as one running slow. Default levels are 30 and 300
 seconds, well inside the tolerance at which single sign-on token
 validation begins to fail.

 By default the service is {CRIT} if time synchronization is disabled, if
 no NTP server is configured, or if none of the configured servers is
 reachable, and {WARN} if only some servers are reachable. All states and
 the drift levels are configurable via the ruleset "VCSA time
 synchronization". Appliances synchronizing from the host rather than NTP
 report no servers, and this is not treated as a fault.

discovery:
 One service is created per appliance.
