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Chapter 3. Using the heat service for autoscaling

After you deploy the services required to provide autoscaling in the overcloud, you must configure the overcloud environment so that the Orchestration service (heat) can manage instances for autoscaling.

Prerequisites

Procedure

After you deploy the services for autoscaling in the overcloud, you must configure the overcloud environment so that the Orchestration service (heat) can manage the instances for autoscaling.

Prerequisites

Procedure

  1. Log in to your environment as the stack user.

  2. For director environments source the overcloudrc overcloud credentials file: 

    $ source ~/overcloudrc

  3. Create the archive policy defined in $HOME/templates/autoscaling/parameters-autoscaling.yaml: 

    $ openstack metric archive-policy create generic \
  --back-window 0 \
  --definition timespan:'4:00:00',granularity:'0:01:00',points:240 \
  --aggregation-method 'rate:mean' \
  --aggregation-method 'mean'

Verification

  • Verify that the archive policy was created: 

    $ openstack metric archive-policy show generic
+---------------------+--------------------------------------------------------+
| Field               | Value                                                  |
+---------------------+--------------------------------------------------------+
| aggregation_methods | mean, rate:mean                                        |
| back_window         | 0                                                      |
| definition          | - timespan: 4:00:00, granularity: 0:01:00, points: 240 |
| name                | generic                                                |
+---------------------+--------------------------------------------------------+

You can configure an Orchestration service (heat) template to create the instances, and configure alarms that create and scale instances when triggered.

Note

This procedure uses example values that you must change to suit your environment.

Prerequisites

Procedure

  1. Log in to your environment as the stack user. 

    $ source ~/overcloudrc

  2. Create a directory to hold the instance configuration for the autoscaling group: 

    $ mkdir -p $HOME/templates/autoscaling/vnf/
  3. Create an instance configuration template, for example, $HOME/templates/autoscaling/vnf/instance.yaml.

  4. Add the following configuration to your instance.yaml file: 

    cat <<EOF > $HOME/templates/autoscaling/vnf/instance.yaml
heat_template_version: wallaby
description: Template to control scaling of VNF instance

parameters:
  metadata:
    type: json
  image:
    type: string
    description: image used to create instance
    default: fedora36
  flavor:
    type: string
    description: instance flavor to be used
    default: m1.small
  key_name:
    type: string
    description: keypair to be used
    default: default
  network:
    type: string
    description: project network to attach instance to
    default: private
  external_network:
    type: string
    description: network used for floating IPs
    default: public

resources:
  vnf:
    type: OS::Nova::Server
    properties:
      flavor: {get_param: flavor}
      key_name: {get_param: key_name}
      image: { get_param: image }
      metadata: { get_param: metadata }
      networks:
        - port: { get_resource: port }

  port:
    type: OS::Neutron::Port
    properties:
      network: {get_param: network}
      security_groups:
        - basic

  floating_ip:
    type: OS::Neutron::FloatingIP
    properties:
      floating_network: {get_param: external_network }

  floating_ip_assoc:
    type: OS::Neutron::FloatingIPAssociation
    properties:
      floatingip_id: { get_resource: floating_ip }
      port_id: { get_resource: port }
EOF
    • The parameters parameter defines the custom parameters for this new resource.
    • The vnf sub-parameter of the resources parameter defines the name of the custom sub-resource referred to in the OS::Heat::AutoScalingGroup, for example, OS::Nova::Server::VNF.

  5. Create the resource to reference in the heat template: 

    $ cat <<EOF > $HOME/templates/autoscaling/vnf/resources.yaml
resource_registry:
  "OS::Nova::Server::VNF": $HOME/templates/autoscaling/vnf/instance.yaml
EOF

  6. Create the deployment template for heat to control instance scaling: 

    $ cat <<EOF > $HOME/templates/autoscaling/vnf/template.yaml
heat_template_version: wallaby
description:  Example auto scale group, policy and alarm
resources:
  scaleup_group:
    type: OS::Heat::AutoScalingGroup
    properties:
      max_size: 3
      min_size: 1
      #desired_capacity: 1
      resource:
        type: OS::Nova::Server::VNF
        properties:
          metadata: {"metering.server_group": {get_param: "OS::stack_id"}}

  scaleup_policy:
    type: OS::Heat::ScalingPolicy
    properties:
      adjustment_type: change_in_capacity
      auto_scaling_group_id: { get_resource: scaleup_group }
      cooldown: 60
      scaling_adjustment: 1

  scaledown_policy:
    type: OS::Heat::ScalingPolicy
    properties:
      adjustment_type: change_in_capacity
      auto_scaling_group_id: { get_resource: scaleup_group }
      cooldown: 60
      scaling_adjustment: -1

  cpu_alarm_high:
    type: OS::Aodh::GnocchiAggregationByResourcesAlarm
    properties:
      description: Scale up instance if CPU > 50%
      metric: cpu
      aggregation_method: rate:mean
      granularity: 60
      evaluation_periods: 3
      threshold: 60000000000.0
      resource_type: instance
      comparison_operator: gt
      alarm_actions:
        - str_replace:
            template: trust+url
            params:
              url: {get_attr: [scaleup_policy, signal_url]}
      query:
        list_join:
          - ''
          - - {'=': {server_group: {get_param: "OS::stack_id"}}}

  cpu_alarm_low:
    type: OS::Aodh::GnocchiAggregationByResourcesAlarm
    properties:
      description: Scale down instance if CPU < 20%
      metric: cpu
      aggregation_method: rate:mean
      granularity: 60
      evaluation_periods: 3
      threshold: 24000000000.0
      resource_type: instance
      comparison_operator: lt
      alarm_actions:
        - str_replace:
            template: trust+url
            params:
              url: {get_attr: [scaledown_policy, signal_url]}
      query:
        list_join:
          - ''
          - - {'=': {server_group: {get_param: "OS::stack_id"}}}

outputs:
  scaleup_policy_signal_url:
    value: {get_attr: [scaleup_policy, alarm_url]}

  scaledown_policy_signal_url:
    value: {get_attr: [scaledown_policy, alarm_url]}
EOF
    Note

    Outputs on the stack are informational and are not referenced in the ScalingPolicy or AutoScalingGroup. To view the outputs, use the openstack stack show <stack_name> command.

3.3. Creating the stack deployment for autoscaling
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Create the stack deployment for the worked VNF autoscaling example.

Prerequisites

Procedure

  1. Log in to the undercloud host with your overcloud administrator credentials, for example overcloudrc: 

    (undercloud)$ source ~/overcloudrc

  2. You must first launch the ephemeral Heat process to use the openstack stack commands: 

    (undercloud)$ openstack tripleo launch heat --heat-dir /home/stack/overcloud-deploy/overcloud/heat-launcher --restore-db
(undercloud)$ export OS_CLOUD=heat

  3. Create the stack: 

    $ openstack stack create \
  -t $HOME/templates/autoscaling/vnf/template.yaml \
  -e $HOME/templates/autoscaling/vnf/resources.yaml \
  vnf

Verification

  1. Verify that the stack was created successfully: 

    $ openstack stack show vnf -c id -c stack_status
+--------------+--------------------------------------+
| Field        | Value                                |
+--------------+--------------------------------------+
| id           | cb082cbd-535e-4779-84b0-98925e103f5e |
| stack_status | CREATE_COMPLETE                      |
+--------------+--------------------------------------+

  2. Verify that the stack resources were created, including alarms, scaling policies, and the autoscaling group: 

    $ export STACK_ID=$(openstack stack show vnf -c id -f value)
     
    $ openstack stack resource list $STACK_ID
+------------------+--------------------------------------+----------------------------------------------+-----------------+----------------------+
| resource_name    | physical_resource_id                 | resource_type                                | resource_status | updated_time         |
+------------------+--------------------------------------+----------------------------------------------+-----------------+----------------------+
| cpu_alarm_high   | d72d2e0d-1888-4f89-b888-02174c48e463 | OS::Aodh::GnocchiAggregationByResourcesAlarm | CREATE_COMPLETE | 2022-10-06T23:08:37Z |
| scaleup_policy   | 1c4446b7242e479090bef4b8075df9d4     | OS::Heat::ScalingPolicy                      | CREATE_COMPLETE | 2022-10-06T23:08:37Z |
| cpu_alarm_low    | b9c04ef4-8b57-4730-af03-1a71c3885914 | OS::Aodh::GnocchiAggregationByResourcesAlarm | CREATE_COMPLETE | 2022-10-06T23:08:37Z |
| scaledown_policy | a5af7faf5a1344849c3425cb2c5f18db     | OS::Heat::ScalingPolicy                      | CREATE_COMPLETE | 2022-10-06T23:08:37Z |
| scaleup_group    | 9609f208-6d50-4b8f-836e-b0222dc1e0b1 | OS::Heat::AutoScalingGroup                   | CREATE_COMPLETE | 2022-10-06T23:08:37Z |
+------------------+--------------------------------------+----------------------------------------------+-----------------+----------------------+

  3. Verify that an instance was launched by the stack creation: 

    $ openstack server list --long | grep $STACK_ID

| 62e1b27c-8d9d-44a5-a0f0-80e7e6d437c7 | vn-dvaxcqb-6bqh2qd2fpif-hicmkm5dzjug-vnf-ywrydc5wqjjc | ACTIVE | None       | Running     | private=192.168.100.61, 192.168.25.99 | fedora36   | a6aa7b11-1b99-4c62-a43b-d0b7c77f4b72 | m1.small    | 5cd46fec-50c2-43d5-89e8-ed3fa7660852 | nova              | host-80.localdomain | metering.server_group='cb082cbd-535e-4779-84b0-98925e103f5e' |

  4. Verify that the alarms were created for the stack:

    1. List the alarm IDs. The state of the alarms might reside in the insufficient data state for a period of time. The minimal period of time is the polling interval of the data collection and data storage granularity setting: 

      $ openstack alarm list
+--------------------------------------+--------------------------------------------+---------------------------------+-------+----------+---------+
| alarm_id                             | type                                       | name                            | state | severity | enabled |
+--------------------------------------+--------------------------------------------+---------------------------------+-------+----------+---------+
| b9c04ef4-8b57-4730-af03-1a71c3885914 | gnocchi_aggregation_by_resources_threshold | vnf-cpu_alarm_low-pve5eal6ykst  | alarm | low      | True    |
| d72d2e0d-1888-4f89-b888-02174c48e463 | gnocchi_aggregation_by_resources_threshold | vnf-cpu_alarm_high-5xx7qvfsurxe | ok    | low      | True    |
+--------------------------------------+--------------------------------------------+---------------------------------+-------+----------+---------+

    2. List the resources for the stack and note the physical_resource_id values for the cpu_alarm_high and cpu_alarm_low resources. 

      $ openstack stack resource list $STACK_ID
+------------------+--------------------------------------+----------------------------------------------+-----------------+----------------------+
| resource_name    | physical_resource_id                 | resource_type                                | resource_status | updated_time         |
+------------------+--------------------------------------+----------------------------------------------+-----------------+----------------------+
| cpu_alarm_high   | d72d2e0d-1888-4f89-b888-02174c48e463 | OS::Aodh::GnocchiAggregationByResourcesAlarm | CREATE_COMPLETE | 2022-10-06T23:08:37Z |
| scaleup_policy   | 1c4446b7242e479090bef4b8075df9d4     | OS::Heat::ScalingPolicy                      | CREATE_COMPLETE | 2022-10-06T23:08:37Z |
| cpu_alarm_low    | b9c04ef4-8b57-4730-af03-1a71c3885914 | OS::Aodh::GnocchiAggregationByResourcesAlarm | CREATE_COMPLETE | 2022-10-06T23:08:37Z |
| scaledown_policy | a5af7faf5a1344849c3425cb2c5f18db     | OS::Heat::ScalingPolicy                      | CREATE_COMPLETE | 2022-10-06T23:08:37Z |
| scaleup_group    | 9609f208-6d50-4b8f-836e-b0222dc1e0b1 | OS::Heat::AutoScalingGroup                   | CREATE_COMPLETE | 2022-10-06T23:08:37Z |
+------------------+--------------------------------------+----------------------------------------------+-----------------+----------------------+

      The value of the physical_resource_id must match the alarm_id in the output of the openstack alarm list command.

  5. Verify that metric resources exist for the stack. Set the value of the server_group query to the stack ID: 

    $ openstack metric resource search --sort-column launched_at -c id -c display_name -c launched_at -c deleted_at --type instance server_group="$STACK_ID"
+--------------------------------------+-------------------------------------------------------+----------------------------------+------------+
| id                                   | display_name                                          | launched_at                      | deleted_at |
+--------------------------------------+-------------------------------------------------------+----------------------------------+------------+
| 62e1b27c-8d9d-44a5-a0f0-80e7e6d437c7 | vn-dvaxcqb-6bqh2qd2fpif-hicmkm5dzjug-vnf-ywrydc5wqjjc | 2022-10-06T23:09:28.496566+00:00 | None       |
+--------------------------------------+-------------------------------------------------------+----------------------------------+------------+

  6. Verify that measurements exist for the instance resources created through the stack: 

    $ openstack metric aggregates --resource-type instance --sort-column timestamp '(metric cpu rate:mean)' server_group="$STACK_ID"
+----------------------------------------------------+---------------------------+-------------+---------------+
| name                                               | timestamp                 | granularity |         value |
+----------------------------------------------------+---------------------------+-------------+---------------+
| 62e1b27c-8d9d-44a5-a0f0-80e7e6d437c7/cpu/rate:mean | 2022-10-06T23:11:00+00:00 |        60.0 | 69470000000.0 |
| 62e1b27c-8d9d-44a5-a0f0-80e7e6d437c7/cpu/rate:mean | 2022-10-06T23:12:00+00:00 |        60.0 | 81060000000.0 |
| 62e1b27c-8d9d-44a5-a0f0-80e7e6d437c7/cpu/rate:mean | 2022-10-06T23:13:00+00:00 |        60.0 | 82840000000.0 |
| 62e1b27c-8d9d-44a5-a0f0-80e7e6d437c7/cpu/rate:mean | 2022-10-06T23:14:00+00:00 |        60.0 | 66660000000.0 |
| 62e1b27c-8d9d-44a5-a0f0-80e7e6d437c7/cpu/rate:mean | 2022-10-06T23:15:00+00:00 |        60.0 |  7360000000.0 |
| 62e1b27c-8d9d-44a5-a0f0-80e7e6d437c7/cpu/rate:mean | 2022-10-06T23:16:00+00:00 |        60.0 |  3150000000.0 |
| 62e1b27c-8d9d-44a5-a0f0-80e7e6d437c7/cpu/rate:mean | 2022-10-06T23:17:00+00:00 |        60.0 |  2760000000.0 |
| 62e1b27c-8d9d-44a5-a0f0-80e7e6d437c7/cpu/rate:mean | 2022-10-06T23:18:00+00:00 |        60.0 |  3470000000.0 |
| 62e1b27c-8d9d-44a5-a0f0-80e7e6d437c7/cpu/rate:mean | 2022-10-06T23:19:00+00:00 |        60.0 |  2770000000.0 |
| 62e1b27c-8d9d-44a5-a0f0-80e7e6d437c7/cpu/rate:mean | 2022-10-06T23:20:00+00:00 |        60.0 |  2700000000.0 |
+----------------------------------------------------+---------------------------+-------------+---------------+

  7. Remove the ephemeral Heat process from the undercloud: 

    (undercloud)$ openstack tripleo launch heat --kill
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