Restrict container resource usage about ciao

[markdryan]

Here's a sample payload

start:
  requested_resources:
     - type: vcpus
       value: 2
     - type: mem_mb
       value: 16
  instance_uuid: 67d86208-b46c-4465-9018-e14187d41
  tenant_uuid: 67d86208-000-4465-9018-fe14087d415f
  docker_image: ubuntu/python
  vm_type: docker
  networking:
    vnic_mac: CA:FE:00:02:02:03
    vnic_uuid: 67d86208-b46c-0000-9018-fe14087d415f
    concentrator_ip: 192.168.200.200
    concentrator_uuid: 67d86208-b46c-4465-0000-fe14087d415f
    subnet: 192.168.111.0/24
    private_ip: 192.168.111.101

memory and vcpus are currently ignored.

[rbradford]

Proposal:

For memory: use -m mem_mb
For cpu: use --cpu-period=50000 --cpu-quota=50000 * vcpus

See https://docs.docker.com/engine/reference/run/

[markdryan]

Just out of a matter of interest why use a period of 50000? Reading the docs the default seems to be 100000. I was just curious as to why we don't use the default. Otherwise the formulas look good.

[rbradford]

Let's use 100ms.