Читать книгу CompTIA Cloud+ Study Guide - Ben Piper, David Higby Clinton - Страница 77

One of the prime advantages of cloud computing is that it enables on-demand computing, allowing you to deploy and pay for the computing capacity that you are actually using. This is an attractive alternative to having to absorb the costs of servers sitting on standby to address any bursts or cyclical higher compute requirements, such as end-of-month processing or holiday sales loads if, for example, you are a retailer.

Autoscaling is a cloud feature that automatically adds and removes resources based on demand. By paying only for what you need when you need it, you can take advantage of the immense computing power of the cloud without having to pay for servers that are just sitting idle during times of low demand.

For example, let's look at a small sporting goods retailer that uses a public cloud provider to host its e-commerce website. During normal operations, the retailer runs and pays for three web servers. During times of high demand, autoscaling will provision additional web servers to match the increased load. For example, the retailer may decide to run a TV commercial on a Saturday afternoon televised game. After the commercial airs, the website experiences a huge traffic spike and an increase of online orders. Once the load subsides to normal levels, autoscaling terminates the additional web servers so that the retailer doesn't have to keep paying for them when they're not needed. This works well because the retailer can match the load on the website with the needed amount of computing, memory, storage, and other back-end resources in the cloud. Combining this pay-as-you-go model with autoscaling maximizes cost efficiency because you don't have to expend money to purchase the hardware for any peak loads or future growth. Autoscaling will just provision more capacity when needed. With automation and rapid provisioning, adding capacity can be as simple as a few clicks in a console, and the resources are immediately deployed!

Contrast this scenario with what would happen without autoscaling. If the retailer were stuck with only three web servers, during the traffic spike the servers might slow down or crash. Adding more servers would be a manual, expensive, and time-consuming process that even in a best-case scenario would take several minutes to complete. By that time, the damage would have already been done.