Using the App-AutoScaler service requires:

App-AutoScaler is disabled by default. To enable it, add the following block to your kubecf-config-values.yaml file.

features:
  autoscaler:
    enabled: true

To disable App-AutoScaler again, update the above block in your kubecf-config-values.yaml so that enabled is set to false.

After making the change above, and any other configuration changes, apply the update by doing the following:

Push the application without starting it first:

tux > cf push MY_APPLICATION --no-start

Attach autoscaling policy to the application:

tux > cf attach-autoscaling-policy MY_APPLICATION MY_POLICY.json

The policy is defined as a JSON file (See Section 23.4, “Policies”) in a proper format (See https://github.com/cloudfoundry/app-autoscaler/blob/develop/docs/policy.md).

Start the application:

tux > cf start MY_APPLICATION

Autoscaling policies can be managed using cf CLI with the App-AutoScaler plugin as above (See Section 23.3.1, “The App-AutoScaler cf CLI Plugin”) or using the App-AutoScaler API (See Section 23.3.2, “App-AutoScaler API”).

A policy identifies characteristics including minimum instance count, maximum instance count, and the rules used to determine when the number of application instances is scaled up or down. These rules are categorized into two types, scheduled scaling and dynamic scaling. (See Section 23.4.1, “Scaling Types”). Multiple scaling rules can be specified in a policy, but App-AutoScaler does not detect or handle conflicts that may occur. Ensure there are no conflicting rules to avoid unintended scaling behavior.

Policies are defined using the JSON format and can be attached to an application either by passing the path to the policy file or directly as a parameter.

The following is an example of a policy file, called my-policy.json.

{
    "instance_min_count": 1,
    "instance_max_count": 4,
    "scaling_rules": [{
        "metric_type": "memoryused",
        "stat_window_secs": 60,
        "breach_duration_secs": 60,
        "threshold": 10,
        "operator": ">=",
        "cool_down_secs": 300,
        "adjustment": "+1"
    }]
}

For an example that demonstrates defining multiple scaling rules in a single policy, refer to the sample of a policy file at https://github.com/cloudfoundry/app-autoscaler/blob/develop/src/integration/fakePolicyWithSchedule.json. The complete list of configurable policy values can be found at https://github.com/cloudfoundry/app-autoscaler/blob/master/docs/policy.md.