Meta: Support CPU hotplug

[adriansr]

User reports that metricbeat needs to be restarted for the system module to pick up new CPUs hotplugged into the system. This is confirmed, system.cpu.cores does not update.

After reviewing the usage of runtime.NumCPU across beats, found out libbeat/metric/system/process/process.go also might calculate wrong CPU% if NumCPU changes. This should be reviewed.

To sum up:

• Fix metricbeat cores metric to detect number of cores at runtime.
• Review process CPU% calculation in libbeat for correctness if NumCPU changes.

FYI:
CPU hotplug in VirtualBox

[tsg]

Is it a matter of reading the number of cores on every fetch? Or do we need to subscribe to something?

[adriansr]

For the metricbeat issue, yes, it as simple as that.

[botelastic]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.