Support Memory constrains

[egernst]

From @devimc on January 22, 2018 15:1

• hot add/remove memory
  issue virtcontainers: hotplug memory with kata-runtime update command #625
  pull request virtcontainers: hotplug memory with kata-runtime update command. #624
• apply memory cgroups in the guest
  issue Memory constraints are not honoured inside the virtual machine #653
  pull request virtcontainers: Apply memory constraints #654
• track how much memory is being used for all containers and decide if a new chunk of memory must be added or not
  virtcontainers: hotplug memory with kata-runtime update command. #624
• check if the maximum number of memory slots impacts container memory footprint
  [WIP] k8s memory resource hotplug #580 (comment)

Notes:

• on x86 only chucks/multiples of 128mb can be added
• memory hot remove is not possible

Copied from original issue: containers/virtcontainers#578

[jcvenegas]

WIP: https://github.com/jcvenegas/runtime-1/tree/memory-hotplug

[WeiZhang555]

Is there any reason for that "on x86 only chucks/multiples of 128mb can be added"? We once got a requirement of tiny VM isolated container with 64M memory

[linzichang]

@jcvenegas @bergwolf Hi, I have seen cpu-hotplug support for "docker update" is done. About "memory-hotplug", I find there is already some implementations like "hotplugMemory", but they haven't combined with kata-runtime update yet. What is the plan for this?