ESXi Server - Why are all my VM's powered off?

I found all the VM's on my ESXi server powered off this morning. How do I review the ESXi logs to see why? I'm like to know if it was due to power failure or manual shutdown or for some other reason. Thank you!
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
Could be difficult ?

Do you have a single ESXi server ?

Do you have vCenter Server ?

Do you have a UPS connected ?

Do you have any other physical devices which reset/powered off at this time?

Do you have VMware HA ?

If you log back into Windows, does it state if the server failed for an unknown reason ? This could indicate a hard shutdown, e.g. power off event, rather than a OS clean shutdown.

I would look at

1. OS Event viewer for events

2. Check /var/log/vmkernel.log (at the console or remotely via SSH)
(all the logs are in this location, BUT, after ESXi restarts, these may not be persistent, unless you have a syslog server or shared storage LUN, where the logs are stored

3. Check each vmware.* log file in the VM folder

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Do you have some management processor in your server like IMM or iLO or IPMI or BMC?
That should have better logs.
SuncoreAuthor Commented:
Thank you both for your help. @Andrew (1. OS Event viewer for events) -< This was the answer that worked for me and confirmed a hard unexpected shutdown. Thank you.
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