Symptoms:

• On ESXi 7.0U3, the hostd service crashes with log messages similar to this are seen in the vobd.log file:

2021-10-21T18:04:28.251Z: [UserWorldCorrelator] 304957116us: [esx.problem.hostd.core.dumped] /bin/hostd crashed (1 time(s) so far) and a core file may have been created at /var/core/hostd-zdump.000. This may have caused connections to the host to be dropped.
2021-10-21T18:04:28.251Z: An event (esx.problem.hostd.core.dumped) could not be sent immediately to hostd; queueing for retry.
2021-10-21T18:04:32.298Z: [UserWorldCorrelator] 309002531us: [vob.uw.core.dumped] /bin/hostd(2103800) /var/core/hostd-zdump.001
2021-10-21T18:04:36.351Z: [UserWorldCorrelator] 313055552us: [vob.uw.core.dumped] /bin/hostd(2103967) /var/core/hostd-zdump.002
2021-10-21T18:04:40.406Z: [UserWorldCorrelator] 317109536us: [vob.uw.core.dumped] /bin/hostd(2104096) /var/core/hostd-zdump.003
2021-10-21T18:04:44.426Z: [UserWorldCorrelator] 321129801us: [vob.uw.core.dumped] /bin/hostd(2104225) /var/core/hostd-zdump.000

VMware vSphere 7.0.x

• This hostd crash is caused by memory corruption in a function that is part of the time service event monitoring (enabled by default)

This issue is resolved in ESXi 7.0 Update 3c.
The issue was also resolved in ESXi 7.0 U3b (No longer available)

Workaround:
To prevent hostd from crashing, disable time service event monitoring by following these directions:

1. On vSphere Client, go to Configure -> System -> Time Configuration tab, select "Network Time Protocol" and click on EDIT button. 



2. From the configuration box, uncheck "Enable monitoring events"



3.  Click the OK button