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What Is AutoScaling? Everything You Need to Know
August 25, 2021
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August 25, 2021
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If an organization or business wants to achieve significant growth, its websites, applications, or other online platforms should be able to handle the corresponding increase in traffic and usage.
Every application draws the necessary computing power from a server or group of servers – also called a server farm – on which the application is hosted. Each server has a limited computing capacity. So what happens when the app needs more power than is currently available? You autoscale.
Autoscaling saves you the time and effort spent manually scaling a server or system to help you meet all potential levels of server load – high or low.
Autoscaling is a way to automatically scale the computing resources of your application based on the load on a server farm. It involves scaling up the resources when there is a spike or rise in web traffic and scaling down when traffic levels are low.
Autoscaling is widely accepted for its versatility, flexibility, and cost-effectiveness. Some of the world's most popular websites, such as Netflix, have opted for autoscaling support to meet the growing and ever-changing consumer needs and demands.
Amazon Web Services (AWS), Microsoft Azure, and Oracle Cloud are some of the most popular cloud computing vendors offering autoscaling services.
Autoscaling is especially relevant today as the world is committing to reduce carbon emissions and their footprint on the planet. The process helps conserve energy by putting the idle servers to sleep when the load is low.
Autoscaling is most beneficial for applications where the load is unpredictable because it promotes better server uptime and utilization. Based on the conditions specified by the system administrator, autoscaling can automatically couple or uncouple from a computing matrix to adjust to the load. This saves electricity and usage bills since many cloud service providers charge based on server usage.
Some of the other benefits of autoscaling are:
A server cluster comprises the main servers and replicated servers made available when traffic spikes. When a user initiates a request, it passes over the internet to a load balancer that communicates to the servers whether to scale up or out its supplementary units.
In fact, the entire process of autoscaling banks on load balancing – it defines the server pool's efficiency in handling traffic.
Based on how servers are called from the circuit, there are three major types of autoscaling.
Reactive autoscaling bases its operation on preset "triggers" or thresholds specified by the administrator, which activates additional servers when crossed. Thresholds can be set for key server performance metrics such as the percentage occupied capacity. For example, reactive autoscaling happens when additional servers are set to kick in when the main server runs at 80% capacity for a full minute.
Essentially, this type of autoscaling "reacts" to incoming traffic.
Suitable for applications where server loads are more or less predictable. Predictive or proactive autoscaling schedules additional servers to kick in automatically during peak traffic times based on the time of day. This type of autoscaling uses artificial intelligence (AI) to “predict” when traffic would be high and schedules server augmentations in advance.
Scheduled autoscaling is similar to predictive autoscaling; the only difference is in scheduling additional servers for peak time. While predictive autoscaling does this autonomously, scheduled autoscaling relies more on human input to schedule the servers.
Any business, large or small, can reap the various benefits of autoscaling services. Below are some of the key advantages of autoscaling:
Applying autoscaling to a website puts servers to sleep during periods of low traffic. This significantly lowers a company’s power consumption when applications are hosted on its in-house server infrastructure.
Most cloud computing service providers charge based on server usage, not capacity. This translates to lower server costs compared to paying for the maximum required capacity regardless of usage. Organizations with massive fluctuations in web traffic, such as online retail stores and travel booking applications during the holiday season, benefit greatly from reduced server costs.
Autoscaling supports effective server load management since servers can be used during periods of low traffic to complete computing tasks that are not time-sensitive. This is possible since autoscaling frees up significant server space when there is less traffic.
Autoscaling services such as those from AWS ensure prompt replacement of faulty instances. This offers an app considerably limited protection against network, application, and hardware failures.
When server loads are highly erratic and unpredictable, such as in e-commerce websites or video streaming services, autoscaling ensures preparedness to handle the varying server demands, making it a dependable option. Server failure is often a costly affair capable of causing tremendous losses to the organization. In 2018, J.Crew's server failure on Black Friday cost them a whopping $700,000 in sales. Amazon India suffered a similar outage in May 2021, with the website being down for a couple of hours, which affected sales.
Various cloud service providers deploy autoscaling through indigenously developed processes or software that help optimize server performance. Let's look at some of these examples in detail.
Amazon Web Services (AWS) sports multiple services for autoscaling: AWS service and Amazon EC2. Amazon EC2 relies on launch templates to derive information about launching instances (like VPC subnet). Users have the option to set the instance count manually or let EC2 do it automatically.
GCE enables autoscaling via Managed Instance Groups (MIGs). Its console gives users the freedom to define MIGs, organize them according to the desired performance metric (such as CPU utilization), adjust them for the required autoscaling cap, and activate autoscaling with a click of a button.
IBM's services work on virtual servers autoscaled through an implement called cluster-autoscaler. Nodes are kicked in or out based on the instance load when the preset threshold is exceeded. This autoscaling mechanism works with workload policies that users define as per sizing needs.
Azure provides its users a console to set autoscale programs. They can just navigate to the autoscale option on their console, add new settings and rules for scaling on various server parameters, and set the conditions for autoscaling.
Oracle Cloud provides full-scale control over autoscaling. It allows users to configure it for metric-based or schedule-based autoscaling. Users can edit and configure autoscaling policies. Oracle offers multiple autoscaling services to elastically balance network load on servers.
Today, autoscaling is a powerful, sophisticated, and useful computing feature that helps millions of websites or apps manage their server loads. However, like traditional scaling, you need to overcome many hurdles to achieve autoscaling. Here are four overarching reasons why autoscaling can be difficult to optimize and apply, especially on large servers with massive amounts of information.
Imagine an e-commerce website with a database of over a million names and customer contacts. Regardless of the site's measures to organize this massive data, scouring it for information is not an easy task. With autoscaling, however, this information needs to be made available at all times across the additional servers – a significant problem to address.
When an e-commerce website opts for autoscaling services, another major hurdle is achieving consistency. For example, during flash sales, product availability data is constantly updated. These changes should be made available to all users on the platform to ensure that no one can place an order for a product no longer available. Ensuring the consistency of information and data in such situations, especially when the server load is high, isn’t simple.
Using the same example above, suppose millions of users are trying to log into the e-commerce website to purchase the same product. Although unlikely, this is the kind of situation a server should be ready for. Each of these users requires simultaneous access to the data and information on the servers. This is a major challenge any autoscaling attempt must overcome.
When it comes to large amounts of information, scaling up or adding a server inevitably affects the speed at which these computing resources can be deployed to provide information to users on the application or website.
Apart from the sheer amount of computing resources and expertise required to tackle the challenges of autoscaling and provide a satisfying customer experience, most cloud service providers don’t offer native autoscaling support because the associated costs are very high.
Cloud-based hosting services that offer autoscaling almost always use horizontal autoscaling to achieve the desired result. This entails deploying additional servers or machines to the existing resource pool versus vertical autoscaling that involves upgrading the existing servers and machines. A good example of vertical autoscaling is increasing RAM capacity in an existing machine. Regardless of the means used to achieve autoscaling, a cloud service provider's expenses are high.
To ensure the efficient management of autoscaling, a dedicated team of experts is needed to oversee and monitor the process, especially for high-traffic websites. For example, in the United States, e-commerce websites such as Shopify or Amazon see more sales during the festive sale season than on Black Friday. Therefore, not all cloud service providers are willing to make the substantial investments required to build a team capable of supporting autoscaling natively on their platforms.
Autoscaling is an increasingly popular web hosting feature that’s undoubtedly here to stay. With enormous dedication and financial backing to the technology and strategy, many tech giants have ensured that consumers now have access to reliable autoscaling features and constantly improve their customer experience.
Organizations interested in making the most of autoscaling can choose either vertical or horizontal autoscaling options. Right off the bat, vertical autoscaling isn’t ideal for web applications or resources with thousands of users since there are several architectural limitations to upgrading existing servers that affect availability.
On the other hand, horizontal autoscaling ensures continued availability. This is because user sessions aren’t restricted to a localized server but seamlessly spread out across a server pool that can be expanded or contracted based on the web application’s ever-changing needs.
Despite the investment required and challenges involved, autoscaling offers organizations several short-term and long-term benefits. Therefore, if an organization wants to scale its operations and web resources, autoscaling is often the best option available.
Achieving high availability for your application can be a chore. Read more about high availability options so you can spot any errors and traffic movements in your application and take optimal action.