I'm tracking CPU usage on a VM on a lightly-loaded host. Everything appears to be functioning normally on all the VMs, but collectd is reporting a gradually increasing 'steal' time:
The actual steal time reported is always either 100% or 0%, but as time passes, the 100% spikes get closer and closer together.
Both VM and host are running vanilla Debian 8. We didn't notice the same effect when both were running Debian 7 on a different physical host.
Is this a quirk of collectd or is KVM really slowly taking CPU resources away from the VM?