As others have implied, you need to have something run on startup that will execute that IPMI tweak again.

In my case ESXi auto-starts my VMs, one of which is a docker VM and it auto starts a container that does the IPMI tweak (and monitors temps and adjusts and all that).

You don’t need to layer it this deep, but fundamentally you need things to auto-start on boot, including this.

I personally, use a bash script, which runs as a daemon, that dynamically sets the fan speed based on temps.

So, under idle, the servers run nearly silent. Under load, the fans can spin up.

When the script/daemon stops, it restores the default fan curve.