Monitoring ESXi host temperature
It is common for customers to monitor the fan speed and temperature of hardware equipment. Rising fan speed or temperature can be a good warning indicator of failure or high utilization.
If you have many ESXis, tracking them one by one is tedious. It also makes more sense to track at the cluster level due to HA, DRS, and VSAN. The following screenshot shows an example of four clusters:
Tracking ESXi temperature
From this, viewers can easily see whether the cluster utilizations are in the healthy range or not. I have adjusted the threshold accordingly so that they display different thresholds. In your environment, they should mostly be green, as they should be within the range you deem healthy.
The blog at http://virtual-red-dot.info/is-any-of-your-esxi-hosts-in-any-of-your-data-centers-overheating/ has the implementation details.
