System clock drifts on ESXi 7.0 U3 or later after synchronization failure with NTP server.

Products

• VMware vSphere ESXi

Issue/Introduction

Symptoms:

When there is a connectivity issue while reaching an NTP server from an ESXi host, the system clock
on the ESXi host might experience a significant drift.

Upon executing the vsish command vsish -e get /system/ntpclock/clockData, a large negative value is recorded in the adjtime field.

NTP clock data {
  Clock state:0
  Clock status:0x00002001
  TAI offset:0
  Maximum error (usec):655420
  Estimated error (usec):349
  Poll shift:6
  Time offset (nsec):-143603
  Freq offset (nsec/sec):12888
  adjtime() (usec):-309237290312 <<<<<<
  tick adjustment (nsec/sec):-4987251
  Ref timer freq (cycles/sec):2399998000

Environment

VMware vSphere ESXi 7.0
VMware vSphere ESXi 8.0

Cause

Known issue on ESXi 7.0 U3 and later.

 

Resolution

This issue has been fixed in ESXi 7.0 Update 3o, ESXi 8.0 Update 1d and ESXi 8.0 Update 2.

Workaround:

To address this issue, one of the following workarounds can be implemented:

• Restore connectivity to the NTP server.
• Reset the ESXi clock state using the following command:

    vsish -e set /system/ntpclock/clockData 1

  Verify that the correct value has been set in the adjtime() function by executing the following command:

    vsish -e get /system/ntpclock/clockData

    NTP clock data {
      Clock state:0
      Clock status:0x00000040
      TAI offset:0
      Maximum error (usec):503000
      Estimated error (usec):500000
      Poll shift:3
      Time offset (nsec):0
      Freq offset (nsec/sec):0
      adjtime() (usec):0 <<<<<
      tick adjustment (nsec/sec):0
      Ref timer freq (cycles/sec):2399998000
    }

 

Additional Information

Impact/Risks:

Failure to synchronize with the NTP server due to loss of connectivity leads to time drift on ESXi hosts. If the connectivity issue is temporary and subsequently resolved, time drift will be corrected eventually.