AWS Certified SysOps Administrator Official Study Guide. Cole Stephen

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СКАЧАТЬ scales out during peak demand to minimize latency, but it also automatically scales in later to minimize spend. You manage an environment that is highly utilized every hour of every day.

Fortifying Systems

      Things break and systems go offline, but you don’t let that keep you up at night. You maintain highly available architectures: systems that detect failed components and automatically switch over, replacing and restoring as needed without interruption of service to your consumers.

      But your availability methods cover more than single regions and multiple Availability Zones. Systems operations on AWS involves using multi-region and hybrid methods when needed to ensure continuity of operations no matter what Mother Nature throws at you.

Securing Systems

      The combination of security groups, access control lists, and private networks in concert with native tools such as Amazon CloudFront and AWS Shield, help your environment stand up to the most sinister of attacks.

      Threats don’t always come from the outside, however. You know that the most dangerous vector is the internal attack. That’s why you have meticulously employed a policy of compartmentalized, restricted privilege sets so that no one can step into unauthorized territory, along with detailed Application Programming Interface (API) logging that reports on all actions to provide comprehensive control over your assets.

      AWS Certified SysOps Administrator – Associate

      As detailed in the introduction to this chapter, AWS systems operators focus on a wide range of responsibilities. The AWS Certified SysOps Administrator – Associate certification is engineered to test your knowledge of systems operations domains. This book not only explains the domains on the exam, but it walks you through the different aspects of AWS with which you must be familiar in order to be successful as an AWS systems operator.

      The test is organized into seven domains of relatively equal weight:

      1. Monitoring and Metrics

      2. High Availability

      3. Analysis

      4. Deployment and Provisioning

      5. Data Management

      6. Security

      7. Networking

      As you explore individual AWS architectures and services, it is important to note that many of the AWS products have operational considerations that apply to most, if not all, seven domains.

      Which AWS Services Should You Study?

      The simple answer is, “all of them.”

      AWS is constantly evolving and adding new offerings. As of this writing, AWS has more than 90 unique services. Each one has security, data, monitoring, and availability considerations. As an AWS systems operator, you are tasked with understanding those considerations along with how to optimize the service for performance and cost. The next few chapters in this book walk you through the service categories, explain how those services are addressed from an operational perspective, and discuss what you should study.

      With more than 90 services and approximately 55 questions, mathematically not every service can be addressed in the certification exam. Commonly used services might appear in many different questions, although services with more specific use cases are much less likely to appear.

      For example, when studying the storage products, you must understand the options found in Amazon Simple Storage Service (Amazon S3), Amazon Elastic Block Store (Amazon EBS), and Amazon Glacier. You can expect these services to appear in questions throughout all of the domains. In contrast, AWS Snowmobile could be on the test, but because it is used only in a few specific scenarios, statistically it is unlikely to appear more than once, if at all.

      The best rule of thumb is to look at common reference architectures. If you see services in those architectures, plan on them being integral to the test. However, do not discount other services; everything is fair game.

      The following section provides specific reference architectures that you can use as you plan on what services to study.

      Reference Architecture: The Three-Tier Design

      One of the earliest cloud-native architectures used is the three-tier design, which includes the following:

      ■ A front-end web server layer

      ■ An application middle layer

      ■ A database layer

      In many cases, the first two layers might be fronted, or decoupled, with elastic load balancers.

Introduction to the Three-Tier Design

      The model of a three-tier architecture was introduced in the late 1990s. It was an evolution from a two-tier architecture (client/server), which was an evolution from a monolithic (mainframe-based) architecture. One of the original drivers for a three-tier architecture was the desire to implement a web-based interface to existing applications, which were currently being accessed via a command-line interface (CLI).

      The focus of this model is on application architecture. Each application has its own unique architecture, which exists independently of any other application.

Web Tier

      The Web Tier is the front end to the application. It accepts the request from the user and passes that request to the Application Tier. It takes the response from the Application Tier and presents it back to the user. The format of the response is controlled at this tier, whether it is an HTML document, a CSV file, a PDF file, or some other format.

      This tier has no direct access to the Database Tier, and it should be decoupled from any processes happening in the Application Tier or the Database Tier.

Application Tier

      The Application Tier is a middleware tier where the internal business logic resides. It responds to requests from the Web Tier and communicates directly with the Database Tier. The Application Tier operates and scales independently of the other tiers.

Database Tier

      The Database Tier is a back-end tier where the databases manage the state of the application. This tier should only be accessed by the Application Tier. It processes requests from the Application Tier and provides responses back to the Application Tier.

Sample Scenario

      To better prepare you for the exam, this book references a few sample architectures. These are provided to give a framework to the discussions. Although the problem we might be addressing is specific, the services we use are universal to most architectures on AWS.

       Three-Tier Architecture

       The Challenge

      An application runs an order management system for a global company. The application will manage inventory, customer records, and orders in an integrated system.

      Some of the system requirements include flexibility to adjust to changing needs. It must be scalable to handle variable customer loads. It must have separate front-end and processing layers to allow User Interface (UI) development to be isolated from business logic programming.

      It must be cost effective. In addition to scalable web and application instances, it should leverage native, cost-effective services such as elastic load balancing and Amazon S3.

      The СКАЧАТЬ