Limit CPU usage Ansible J2 loop

raw

3/6/24, 11:44 AM

I have an Ansible task that formats a list of VLANs. However, when I run the task with multiple forks, it causes my CPU usage to spike to 100% for a long time. How can I optimize the task to reduce CPU usage or limit the CPU usage of this task ?

Here's the original task:

- name: Fromat VLAN list
  ansible.builtin.set_fact:
    device_interface_vlans: "{{ dict(key | zip(val)) }}"
  vars:
    dev_ifc_str: |-
      {% for vlan in ansible_facts.napalm_vlans.keys() %}
      {% for int in ansible_facts.napalm_vlans[vlan]['interfaces'] %}
      - {int: {{ int }}, vlan: {{ nb_vlans | selectattr('vid', 'equalto', vlan | int) | map(attribute='id') | join }}}
      {% endfor %}
      {% endfor %}
    int_vlan: "{{ dev_ifc_str | from_yaml }}"
    arr: "{{ int_vlan | groupby('int') }}"
    key: "{{ arr | map('first') | list }}"
    val: "{{ arr | map('last') |
      map('json_query', '[].vlan') |
      map('community.general.dict_kv', 'vlans') | list }}"

I have already tried cpulimit but it is limiting the cpu usage of each forks and not all of them.

1 + 0

ansible

Score:1

Server

raw

3/7/24, 9:37 AM

I fixed it by using json_query wich is wayyyy faster:

    - ansible.builtin.set_fact:
        device_interface_vlans: "{{ dict(key | zip(val)) }}"
      vars:
        dev_ifc_str: |-
          {% for vlan in ansible_facts.napalm_vlans.keys() %}
          {% for int in ansible_facts.napalm_vlans[vlan]['interfaces'] %}
          - {int: {{ int }}, vlan: {{ nb_vlans | json_query('[?vid == `{}`].id'.format(vlan | int)) | join }}}
          {% endfor %}
          {% endfor %}
        int_vlan: "{{ dev_ifc_str | from_yaml }}"
        arr: "{{ int_vlan | groupby('int') }}"
        key: "{{ arr | map('first') | list }}"
        val: "{{ arr | map('last') |
          map('json_query', '[].vlan') |
          map('community.general.dict_kv', 'vlans') | list }}"

+ 0

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EN: Limit CPU usage Ansible J2 loop

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