PAI EAS scheduled auto scaling - Platform For AI - Alibaba Cloud Documentation Center

Console configuration

Enable scheduled auto scaling

Log on to the PAI console. Select a region on the top of the page. Then, select the desired workspace and click Elastic Algorithm Service (EAS).
In the service list, click the target service to open its Overview page.
On the Auto Scaling tab, in the Scheduled Scaling section, click Enable Scheduled Scaling.

In the CronHPA Settings dialog box, configure the following parameters. Click Add to add multiple tasks. Click OK when finished.

Parameter	Description
Task Name	Scheduled scaling task name.
Target Replicas	Target replica count.
Scaling Schedule	Task execution time. Set using one of these options: Week: Recurring weekly schedule. Day: Recurring daily schedule. Cron Expression: Custom schedule using a cron expression.

Update configuration

On the Auto Scaling tab, in the CronHPA section, click Manage CronHPA.
In the CronHPA Settings dialog box, modify Task Name, Target Replicas, or Scaling Schedule as needed.
Click Update.

Disable scheduled auto scaling

On the Auto Scaling tab, in the CronHPA section, click Disable Scheduled Scaling.
In the Confirm Disable dialog box, click Confirm.

Local client configuration

Enable or update scheduled auto scaling

Scheduled Scaling is disabled by default. Log on to the eascmd client and run the cronscale subcommand to enable or update it. For logon instructions, see Download and authenticate the client.

Command format (Windows 64-bit)

eascmdwin64.exe cronscale [region]/[service_name] -s cronscale.json

Configure the cronscale.json file as described in the following table. Sample configuration:

{
  "ExcludeDates": ["* * * * * 6,0"],
  "ScaleJobs": [
    {
      "Schedule": "0 15,45 * * * *",
      "TargetSize": 6
    },
    {
      "Schedule": "0 0,30 * * * *",
      "TargetSize": 1
    },
    {
      "Schedule": "0 7,22,37,52 * * * *",
      "TargetSize": 3
    }
  ]
}

Parameter

Description

Example

ExcludeDates

Excluded times specified as cron expressions. Scheduled tasks matching these expressions are skipped. For cron expression syntax, see Cron expressions.

Note

If a cron expression in ScaleJobs matches an expression in ExcludeDates, the task is not executed.

["* * * * * 0,6"]

Scheduled scaling tasks do not execute on Saturdays or Sundays.

ScaleJobs

Scheduled scaling tasks. Each task contains Schedule, TargetSize, and Name parameters:

Schedule: Task execution time as a cron expression. For cron expression syntax, see Cron expressions.
TargetSize: Target number of replicas.
Name: Custom task name (optional).
The Name parameter must meet these requirements:
- Contains only letters and numbers.
- Maximum 20 characters.

[ { "Schedule": "0 0 18 * * *", "TargetSize": 10, "Name": "scale-up" }, { "Schedule": "0 0 22 * * *", "TargetSize": 3, "Name": "scale-down" }]

Scales out to 10 replicas at 18:00 every day and scales in to 3 replicas at 22:00 every day.

View configurations

Command format (Windows 64-bit)

eascmdwin64.exe cronscale show [region]/[service_name]
[RequestId]: F4C38D2D-4B38-5CB7-B706-9A1C41D4617E
+--------------+----------------------------+---------+------------+----------------------+
|     NAME     |          SCHEDULE          |  STATE  | TARGETSIZE |    LASTPROBETIME     |
+--------------+----------------------------+---------+------------+----------------------+
| scale-jobs-1 | 0 5,15,25,35,45,55 * * * * | Succeed |          1 | 2022-03-03T13:45:00Z |
| scale-jobs-0 | 0 0,10,20,30,40,50 * * * * | Succeed |          4 | 2022-03-03T13:50:00Z |
+--------------+----------------------------+---------+------------+----------------------+

Disable scheduled auto scaling

Command format (Windows 64-bit)

eascmdwin64.exe cronscale rm [region]/[service_name]

Compatibility between scheduled and horizontal auto scaling

Scheduled Scaling (Cronscaler) and Horizontal Auto Scaling (Autoscaler) can run simultaneously. When both are enabled, Cronscaler modifies the Autoscaler min or max values.

Important

Cronscaler permanently modifies the Autoscaler configuration. The original configuration remains in effect until the next scheduled scaling event. Service updates or upgrades revert the Autoscaler settings to their original values.

The following rules determine the min and max values when both are enabled.

Horizontal auto scaling min/max	Scheduled auto scaling	Current number of replicas	Final result	Description
1/10	5	5	Horizontal (min/max): 1/10 Number of replicas: 5	Target matches current replica count. No change occurs.
1/10	4	5	Horizontal (min/max): 1/10 Number of replicas: 5	Target is lower than current replica count. Count is retained.
1/10	6	5	Horizontal (min/max): 6/10 Number of replicas: 6	Cronscaler target exceeds current replica count. Target is retained. Cronscaler target exceeds Autoscaler minimum. Autoscaler lower limit is modified.
5/10	4	5	Horizontal (min/max): 4/10 Number of replicas: 5	Cronscaler target is lower than current replica count. Current count is retained. Cronscaler target is lower than Autoscaler minimum. Autoscaler lower limit is modified.
5/10	11	5	Horizontal (min/max): 11/11 Number of replicas: 11	Cronscaler target exceeds current replica count. Target is retained. Cronscaler target exceeds Autoscaler maximum. Autoscaler upper limit is modified.

Cron expressions

Scheduled Scaling uses cron expressions to define task schedules.

Cron expression

Special characters
- Asterisk (*)
  
  Represents any value. For example, 0 0 0 1 * * represents 00:00 on the first day of each month.
- Hyphen (-)
  
  Represents a continuous range of values. For example, 0 0 12-14 * * * represents 12:00, 13:00, and 14:00 every day.
- Comma (,)
  
  Represents multiple discrete values. For example, 0 0 12,14 * * * represents 12:00 and 14:00 every day.
- Slash (/)
  
  Represents an incremental interval. For example, 0 */15 * * * * triggers at 0, 15, 30, and 45 minutes past each hour. Combine with hyphen (-). For example, 0 5-40/15 * * * * triggers every 15 minutes from minute 5 to minute 40 of each hour. Valid time points are 5, 20, and 35 minutes past the hour.

Time parameter descriptions

Name	Valid values	Valid special characters
Second	0-59	* / , -
Minute	0-59	* / , -
Hour	0-23	* / , -
Day	1-31	* / , -
Month	1-12 or JAN-DEC	* / , -
Week	0-6 or SUN-SAT	* / , -

FAQ

How do I use scheduled scaling to automatically start and stop a service?

Set the replica count to a positive value to start the service and to zero to stop it.

Configure two scheduled tasks:
- Scale-up (Start): Scale Expected Instances to 1 at your desired start time (e.g., 8:00 AM).
- Scale-down (Stop): Scale Expected Instances to 0 at your desired stop time (e.g., 8:00 PM).
The service runs and incurs costs only during the scheduled active hours.

References

For metric-based auto scaling, enable horizontal auto scaling. For more information, see Horizontal auto scaling.
For unlimited scaling capacity in dedicated resource groups, use the EAS elastic resource pool. For more information, see Elastic resource pool.