set_libvirt_cpu_quota.yml

---
- hosts: compute_hosts
  gather_facts: true
  vars:
    # We leave 1 full CPU as a spare one for hypervisor
    cpu_spare: "{{ ansible_processor_threads_per_core }}"
    cpu_quota: "{{ ansible_processor_vcpus * 100 - cpu_spare * 100 }}%"
  tasks:
    - name: Update machine.slice
      blockinfile:
        path: /etc/systemd/system/machine.slice.d/override.conf
        create: yes
        block: |
          [Slice]
          CPUQuota={{ cpu_quota }}

    - name: Reaload machine.slice
      systemd:
        daemon_reload: yes

    - name: Applying quota for runtime
      command: systemctl set-property --runtime machine.slice "CPUQuota={{ cpu_quota }}"