# Overview

AS policies can trigger scaling actions to adjust bandwidth or the number of instances in an AS group. An AS policy defines the conditions for triggering a scaling action and the operation that will be performed. When the triggering condition is met, a scaling action is triggered automatically.

If multiple AS policies are applied to an AS group, a scaling action is triggered as long as any of the AS policies is invoked, provided that the AS policies do not conflict with each other.

#### AS supports the following policies:

- Alarm policy: AS automatically adjusts the number of instances in an AS group or sets the number of instances to the configured value when an alarm is generated for a configured metric, such as CPU Usage.
- Scheduled policy: AS automatically increases or decreases the number of instances in an AS group or sets the number of instances to the configured value at a specified time.
- Periodic policy: AS automatically increases or decreases the number of instances in an AS group or sets the number of instances to the configured value at a configured interval, such as daily, weekly, and monthly.

#### Resource Adjustment Modes

- Dynamic

  AS adjusts the number of instances or bandwidth when an alarm policy is triggered.

  This mode is suitable for scenarios where workloads are unpredictable. Alarm policies are used to trigger scaling actions based on real-time monitoring data (such as CPU usage) to dynamically adjust the number of instances in the AS group.

- Planned

  AS adjusts the number of instances or bandwidth when a periodic or scheduled policy is triggered.

  This mode is suitable for scenarios where workloads are periodic.

- Manual

  AS allows you to adjust resources by manually adding instances to an AS group, removing instances from an AS group, or changing the expected number of instances.

Parent topic: AS Policy