[receiver/vcenter] vcenter.vm.disk.utilization was inproperly calculated

[schmikei]

Describe the bug

• Metric was improperly calculated like this:

diskUtilization := float64(diskUsed) / float64(diskFree) * 100

when it should be calculated like

diskUtilization := float64(diskUsed) / float64(diskFree+diskUsed) * 100

Steps to reproduce
Looking at a live environment in Google Cloud noticed the value was incorrect.

What did you expect to see?

For our example storage uncommitted was 10539597824 bytes and committed was 139787059517 bytes which should be calculated as

$$139787059517 bytes ÷ (10539597824 bytes + 139787059517 bytes) * 100% = 92.9888696985 %$$

What did you see instead?

The value was rather
139787059517 bytes ÷ (10539597824 bytes) * 100% = 1398 %

Additional context

Will have a PR shortly to fix calculation.

[djaglowski]

@schmikei, please create separate issues for the various changes you are proposing.

[djaglowski]

There appear to be three unrelated changes here, so an issue for the cpu metric, and another for the resource label.

[schmikei]

Alright I'll separate them out 👍

[schmikei]

@djaglowski I think this should work but let me know if anything needs changes!

• [receiver/vcenter] vcenter.vm.disk.utilization calculation fix  #12343
• [receiver/vcenter] remove uncollected vcenter.vm.cpu.utilization #12359
• [receiver/vcenter] Add vcenter.cluster.name resource attribute to datastore metrics #12360