[ClusterLabs] staggered resource start/stop

[d tbsky]

Klaus Wenninger <kwenning at redhat.com>
> In this case it might be useful not to wait some defined time
> hoping startup of the VM would have gone far enough that
> the IO load has already decayed enough.
> What about a resource that checks for something running
> inside the VM that indicates that startup has completed?
> Don't remember if the VirtualDomain RA might already
> have such a probe possibility.

   in my experience, windows will eat most of disk IO, but linux
suffers. rhel7/rhel8 sometimes timeout mount /boot or / when disk IO
is too heavy, but windows always boot successfully.
resource check inside the VM is good, but I wonder if detecting failed
for some reason the cluster will stuck. in my case I think boot by
order and  delay can solve 99% of problem. it just looks a little
complex with many delay RA.