Rackspace Auto Scale Control Panel User Guide - Create a scaling policy
Last updated on: 2020-09-25
Authored by: Rackspace Support
The Create a scaling group article describes how to set the parameters for scaling policies through the scaling group configuration. This section discusses the Auto Scale current policy options and how group configurations affect policy execution. A scaling policy determines what actions the scaling group take and when they are taken. You can create scaling policies for an existing scaling group at any time by returning to the group configuration page. Typically, you will create at least two policies: one to scale up and one to scale down. You can create up to 1000 policies per group.
There are two steps to create a scaling policy:
Create a scaling policy
- On the Create Scaling Group page, click Create Policy.
- Enter information for the following values:
- Name: Specify a name for the policy, for example, Scale up by 10 on Fridays at 5p.m.
- Scale Trigger: Select how the policy will be triggered, either by a
specific schedule or a webhook. Fill in the schedule or webhook
information according to your selection:
- Scheduled (repeating): Specify how often the policy will occur and when.
- Scheduled (once): For one occurrence.
- Scheduled (cron): Enter a cron expression. You can click Cron Expression Helper then copy the expression into Auto Scale.
- Webhook URL: You must create and configure the webhook by using the Auto Scale API. To learn more about this, read about Webhooks in the Auto Scale API Developer’s Guide.
- Amount: Select Scale Up or Scale Down, enter an integer, and select Servers or Percent. If you specify Scale Up by 2 Servers, the policy will add two servers to your scaling group when the policy is triggered. If you specify Scale Up by 2 Percent, the policy will add servers to equal the equivalent of two percent of your current scaling group, whatever size it is. See Scale Up by Percentage Policy for a visual explanation.
- Cooldown Period: The policy cooldown, prevents a policy from being executed too frequently. For schedule-based policies, we advise leaving this value empty or setting it to 0 (zero). This option is available for Scheduled (cron) and Webhook URL triggers only.
- Click Create Policy. The dialog box closes and the scaling policy that you created is added to the list of scaling policies on the page.
Test your configuration
After the scaling group and scaling policy are created, configuration can be tested by changing the minimum number of entities for the group and watching the new server or servers being added.
After you have created a scaling group and policy, following are some next steps that you might take:
To learn about the Auto Scale API, see the Rackspace Auto Scale Developer Guide.