Read Replicas This section covers the following official AWS Certified SysOps Administrator – Associate (SOA-C02) exam domain: Domain 2: Reliability and Business Continuity CramSaver If you can correctly answer these questions before going through this section, save time by skimming the Exam Alerts in this section and then completing the Cram Quiz at the end […]

CloudFront Security CloudFront is also inherently secure against distributed denial-of-service (DDoS) attacks because the content is distributed to more than 200 locations around the globe. An attacker would need to have a massive, globally distributed botnet to be able to attack your application. On top of the benefit of the distributed architecture, CloudFront is also […]

Redis The other engine supported by ElastiCache is Redis, a fully-fledged in-memory database. Redis supports much more complex datasets such as tables, lists, hashes, and geospatial data. Redis also has a built-in push messaging feature that can be used for high-performance messaging between services and chat. Redis also has three operational modes that give you […]

ExamAlert When choosing a caching strategy, always consider the rate of data change and choose the correct time-to-live (TTL) of the data in the cache, to match the rate of change of the data. Data on an e-commerce site such as item descriptions, reviews, and images are unlikely to change frequently, but data such as […]

Edge Caching When content is delivered frequently to multiple users, you can employ edge caching or what is more commonly referred to as a content delivery network. In AWS, you can use the Amazon CloudFront service to deliver frequently used content in a highly efficient manner to millions of users around the globe while at […]

CramSaver If you can correctly answer these questions before going through this section, save time by skimming the Exam Alerts in this section and then completing the Cram Quiz at the end of the section. 1. You have implemented autoscaling on both the web and app tier of your three-tier application, but in times of high […]

Predictive Scaling Another AutoScaling feature is predictive scaling, which uses machine learning to learn the scaling pattern of your application based on the minimum amount of historical data. The machine learning component then predicts the scaling after reviewing CW data from the previous 14 days to account for daily and weekly spikes as it learns […]

AWS Autoscaling After you design all the instance layers to be scalable, you should take advantage of the AWS Autoscaling service to automate the scale-in and scale-out operations for your application layers based on performance metrics—for example, EC2 CPU usage, network capacities, and other metrics captured in the CloudWatch service. The AutoScaling service can scale […]

ExamAlert Remember, one of the crucial factors that enables scalability and elasticity is ensuring your resources are disposable. That means any data is always written outside the processing layer. All databases, files, logs, and any kind of output the application generates should always be decoupled from the processing layer. In the exam, different services might […]

Answers 1. Answer: Both the web and database layers are scalable. The application layer is limited in elasticity due to the persistence of the session data on the EC2 instances. Session data should be moved off the EC2 instances. 2. Answer: The bulk image uploads seem to exceed the capacity of the ECS cluster. The application needs […]