vm resources: set VM use value to min value

[boddumanohar]

lets say a VM requests 16vCPu and 65Gi of Memory,

this is what we set on the VM object

    Cpus:
      Max:             64
      Min:             500m
      Use:             16
    Memory Slot Size:  512Mi
    Memory Slots:
      Limit:  130
      Max:    256
      Min:    4
      Use:    130

For the pod to be initially schedulable, there should be atleast 16vCPU and 65Gi of memory available on the nodes. And then after the VM starts, the autoscaler will bring the allocated resources down based on the usage.

But instead, we can start the VM with minimum values and based on the VM's resource usage the autoscaler will increase the size of the VM automatically based on the usage.

[noctarius]

Is this compatible with #566 ?

[boddumanohar]

No, both of them solves different problems. This PR set use to min values. The other PR adjusts the memory limits.

[noctarius]

Compatible not "the same" :)

[boddumanohar]

Got it. yeah I guess they are compatible.

[mxsrc]

If I understand this correctly, this initially sets use to min instead of desired, and introduces setting the limit for CPU resources as well, right?

I agree with both changes, for resizing though I don't think we should touch use. The VM is already running and settled at whatever value is appropriate. If it needs to scale down due to the lower limit it'll do that on its own, no need to interrupt the process by bringing it to the bare minimum. Though I suspect the use-value wouldn't even be applied in that case, but still.

[boddumanohar]

Good catch, yeah during resize, we don't need to set use during resize. Just setting the limit would be sufficient.