Troubleshooting ESXi host reboots

 

As part of troubleshooting,  check boot history of esxi hosts. In vCenter, we can able to see uptime details on summary tab of esxi hosts.

what is the vmksummary.log

A summary of ESXi host startup and shutdown, and an hourly heartbeat with uptime, number of virtual machines running, and service resource consumption.
Take shh of esxi host and find the logs.
And run the below command to get all logs of hosts.
# uptime
( since esxi host up state)
# cd /var/log
# cat vmksummary.log
# /var/log/vmksummary.log
To get specifc boot history of esxi hosts, run the below command.
#grep booted /var/log/vmksummary.log
out put:
 vSphere Security documentation for more information.
[root@esxi:~] grep booted /var/log/vmksummary.log
2022-06-23T14:08:25Z bootstop: Host has booted
2022-07-04T08:32:55Z bootstop: Host has booted
2022-07-04T08:41:10Z bootstop: Host has booted
[root@esxi:~]
As you can see  host was rebooted 3 times and find the below image