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Introduction to Alibaba Auto Scaling



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Introduction to Alibaba Auto Scaling

This course explores Alibaba Auto Scaling. We'll look at the main applications of the Auto Scaling service and you'll follow along with practical demonstrations direct from the Alibaba Cloud platform to learn how to use each auto scaling service.

Learning Objectives

  • Get a basic understanding of Alibaba Auto Scaling
  • Learn about key auto scaling concepts
  • Understand the core functions of auto scaling, including scaling group,s scaling configurations, and scaling rules
  • Learn how to trigger scaling manually and how to create triggers for automatic scaling events

Intended Audience

This course is intended for anyone looking to use auto scaling to manage their Alibaba Cloud workloads, as well as anyone studying for the ACP Cloud Computing certification exam.


To get the most out of this course, you should have a basic understanding of the Alibaba Cloud platform.


Let's start by looking at the problem that Auto Scaling is trying to address. The problem is how can we scale services automatically to match demand? That's the core critical issue that Auto Scaling tries to address. And we need to worry about this because there are multiple applications and scenarios, such as video streaming or gaming or load changes day by day or even hour by hour. Sometimes the change in load is unpredictable. Sometimes we can predict it in advance. In the case of gaming, for instance, most gaming takes place in the evening, but in either of these cases, we have a simple problem we need to solve, which is we need to scale our system to meet that demand, regardless of whether or not we can plan for it in advance.

How can we do that? What we want to do is try to adjust our resources to match the demand curve, to match the number of requests that are coming in for our web application or web service. We don't want to have to do this manually. We would like to do it automatically if possible. And Auto Scaling's job is to help us automate that process. So what Auto Scaling does on Alibaba Cloud's platform is it automatically creates and releases ECS instances based on policies that you, as the user specify. Further, it can configure Server Load Balancer and RDS whitelists without any manual intervention from you.

So as servers are added, they automatically gain permissions to access RDS databases and automatically get registered with your server load balancer. Similarly, when an instance is removed by Auto Scaling, it's removed from the RDS whitelist, and it is also deregistered from the Server Load Balancer. So it fully automates the process of scale-out and scale-in. Let's address those concepts in a little bit more detail.

So what is scale-out? Scale-out is simply adding more ECS instances to the Auto Scaling group. So Auto Scaling maintains a group or pool of ECS instances and scaling-out means adding additional instances to that group. Scale-in is just the opposite. Unlike scale-out, scale-in removes instances from the pool.

Now, why would you want to do that? Well, of course, your peak demand and your average demand probably aren't the same. When your system is not under heavy load, you might want to cut costs by removing unnecessary ECS instances. You can reduce the number of resources you're currently using when your demand is low. This saves you money. Another area where Auto Scaling service has value is in health checking and elastic self-healing. So, the Auto Scaling cluster or group can monitor the ECS instances that are part of the group and if one of them is detected to be unhealthy, meaning it fails a health check, then it can be removed from the pool and replaced by a new healthy ECS instance, which allows your service to self heal.

So let's recap. Auto Scaling is a management service that allows users to automatically adjust elastic compute resources according to business needs and policies. And there are multiple modes. In fact, we just discussed the three modes that Auto Scaling supports. There's elastic scale-out in which we add additional computing resources to the pool during peak times. There's scale-in, when we release ECS instances as the load reduces. And then there's elastic self-healing in which we detect and replace unhealthy servers, unhealthy ECS instances. That's all for this section. In the next section, let's look at some Auto Scaling core concepts.

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Alibaba Cloud, founded in 2009, is a global leader in cloud computing and artificial intelligence, providing services to thousands of enterprises, developers, and governments organizations in more than 200 countries and regions. Committed to the success of its customers, Alibaba Cloud provides reliable and secure cloud computing and data processing capabilities as a part of its online solutions.