Auto Scaling

Prerequisites

The service status is Running, Abnormal, or Alarm.

Constraints

• Real-time services deployed in a public resource pool do not support auto scaling.
• Scaling is not allowed when a service is stopped, abnormal, being deployed, or being scaled.
• At least one policy rule must be configured.

Procedure

1. Log in to the ModelArts management console. In the navigation pane on the left, choose Service Deployment > Real-Time Services. The Real-Time Services page is displayed.
2. Click the check box next to the service name to display the hidden view at the bottom of the list. (If the view is not displayed, click in the bottom right corner.)
3. Click Resize Compute Resources in the Operation column of the target AI application version.
   Figure 1 Resize Compute Resources
   
4. Configure parameters. The service name, current AI application version, resource pool, AI application and version, and compute node specifications cannot be modified.

   Auto Stop: This parameter is displayed if auto stop is enabled for the service. The service will automatically stop upon the specified time. You can click Modify to change the auto stop time.

   If Resize Type is set to Auto, you can set or reset scaling rules.

   • Configuring a scaling policy
     The following table lists the parameters.

     Table 1 Policy parameters

     Parameter	Description
     Policy Name	Name of a scaling policy. The value can contain 1 to 64 visible characters, including only lowercase letters, digits, hyphens (-), and periods (.), and must start or end with a letter or digit.
     Trigger Type	Scheduled: Set a scheduled scaling policy to trigger scaling at a specified time. Scheduling Rule: You can view, add, and delete scheduling rules, and set whether to enable scheduling rules.

     • Viewing a rule

       In the scheduling rule list, you can view the rule name, status, rule type, triggering condition, number of target instances, whether to enable the rule, and operations.

       The rule statuses include Creating, Configured, Configuration failed, Triggered, Trigger failed. If a rule has been configured but not triggered, its status is Configured. After a rule is triggered and the resource pool is resized, the rule status is Triggered. If a rule is created when the service is stopped, the status is Creating. After the service is started, the rule is automatically configured.

       

       If a scheduling rule is always in the Creating state, the resource pool version may be too old. In this case, contact Huawei technical support.

     • Adding a rule

       Click Add. In the Add Rule dialog box that appears, configure parameters and click OK.

       The following table describes the rule parameters.

       Table 2 Rule parameters (scheduled triggering)

       Parameter	Description
       Rule Name	The value can contain only lowercase letters, digits, hyphens (-), and periods (.), and must start and end with a letter or digit. The rule name must be unique. A maximum of 20 characters are supported.
       Target Instances	Set the number of target instances for scaling.
       Triggered	Choose when to run the rule. You can set it to run daily, weekly, monthly, or at a custom time using a cron expression. This time indicates the local time of where the node is deployed. For details about how to use a cron expression, see Cron Expression.

       

       You can add a maximum of 10 rules.

     • Deleting a rule

       Click Delete in the Operation column of the scheduling rule you want to remove.

     • Enabling or disabling a rule

       Click the button in the Enable column of the scheduling rule you want to enable or disable. After a rule is disabled, it does not take effect.

5. After you click Next and Submit, the service automatically resizes based on the configured scaling policy.

Cron Expression

You can use a cron expression to trigger auto scaling. A cron expression is in the format of "Minute Hour Date Month Week". For example, 30 10 15 * * indicates that the rule is triggered at 10:30 on the 15th day of each month. You must set the cron expression based on the local time zone.

• Time parameters

  Table 3 Time parameters

  Parameter	Option	Available Special Character
  Minute	0 to 59	* , - /
  Hour	0 to 23	* , - /
  Day	1 to 31	* , - /
  Month	1 to 12 or JAN to DEC	* , - /
  Day in a week	0 to 6 or SUN to SAT	* , - /

• Special characters

  Table 4 Special characters

  Special Character	Description
  Wildcard (*)	Can be any value. For example, 0 0 1 * * indicates 00:00 on the first day of each month.
  Comma (,)	Separates items in a list. For example, 0 12,16 * * * indicates 12:00 and 16:00 every day.
  Hyphen (-)	Indicates a value range. For example, 0 12,16 * * * indicates 12:00 to 16:00 every day.
  Slash (/)	Indicates the range increment. For example, */10 * * * * indicates the 0th minute, 10th minute, 20th minute, 30th minute, 40th minute, and 50th minute of each hour. A slash can be used together with a hyphen. For example, 3-59/15 * * * indicates that a value is obtained every 15 minutes from the 3rd minute to the 59th minute in an hour. The valid time points can be 0:03, 0:18, 0:43, and 0:58.