I'm trying to learn how to deploy instances able to auto scale using the ceilometer and aodh plugins for monitoring and alarming on DevStack Ocata, following the instructions presented on https://docs.openstack.org/tacker/ocata/devref/alarm_monitoring_usage_guide.html (this link). After a few tests using the Ubuntu Server 16.04 as the VDU OS with a stress tool to constantly use 100% of the CPU capacity, I've noticed that the scaling operation would not be triggered and the alarm state would always show "insufficient data".

After this, I've done a few modifications to the TOSCA file displayed on the tutorial trying to simplify the situation and get a better understanding of what is going on.

This is was the resulting code, which also still does not work:

tosca_definitions_version: tosca_simple_profile_for_nfv_1_0_0
description: Demo example

metadata:
 template_name: sample-tosca-vnfd

topology_template:
  node_templates:
    VDU1:
      type: tosca.nodes.nfv.VDU.Tacker
      capabilities:
        nfv_compute:
          properties:
            disk_size: 10 GB
            mem_size: 2048 MB
            num_cpus: 1
      properties:
        image: ubuntu-server-16.04
        mgmt_driver: noop
        availability_zone: nova
        metadata: {metering.vnf: SG1}

    CP1:
      type: tosca.nodes.nfv.CP.Tacker
      properties:
        management: true
        anti_spoofing_protection: false
      requirements:
        - virtualLink:
            node: VL1
        - virtualBinding:
            node: VDU1

    VL1:
      type: tosca.nodes.nfv.VL
      properties:
        network_name: net_mgmt
        vendor: Tacker

  policies:
    - SP1:
        type: tosca.policies.tacker.Scaling
        properties:
          targets: [VDU1]  
          increment: 1
          cooldown: 30
          min_instances: 1
          max_instances: 3
          default_instances: 1

    - vdu1_cpu_usage_monitoring_policy:
        type: tosca.policies.tacker.Alarming
        triggers:
            resize_compute:
                event_type:
                    type: tosca.events.resource.utilization
                    implementation: ceilometer
                metrics: cpu_util
                condition:
                    threshold: 70
                    constraint: utilization greater_than 70%
                    period: 120
                    evaluations: 1
                    method: avg
                    comparison_operator: gt
                metadata: SG1  
                actions: [SP1]

And this is my local.conf file:

[[local|localrc]]
ADMIN_PASSWORD=secret
DATABASE_PASSWORD=$ADMIN_PASSWORD
RABBIT_PASSWORD=$ADMIN_PASSWORD
SERVICE_PASSWORD=$ADMIN_PASSWORD

CEILOMETER_PIPELINE_INTERVAL=10

enable_plugin heat https://git.openstack.org/openstack/heat stable/ocata
enable_plugin tacker https://git.openstack.org/openstack/tacker stable/ocata
enable_plugin ceilometer https://git.openstack.org/openstack/ceilometer stable/ocata
enable_plugin aodh https://git.openstack.org/openstack/aodh stable/ocata

I'm still researching about the Ceilometer and Aodh plugins at the moment, but I don't know what should be done in order to get this to work. Can anyone shed a light on how can I proceed here?