Amazon Web Services Updated CLF-C02 Exam Questions and Answers by md

Amazon EC2 instance store provides temporary block-level storage for your EC2 instance. This storage is located on disks that are physically attached to the host computer. Instance store is ideal for temporary storage of information that changes frequently, such as buffers, caches, scratch data, and other temporary content. It can also be used to store temporary data that you replicate across a fleet of instances, such as a load-balanced pool of web servers. An instance store consists of one or more instance store volumes exposed as block devices. The size of an instance store as well as the number of devices available varies by instance type and instance size. The virtual devices for instance store volumes are ephemeral[0-23]. Instance types that support one instance store volume have ephemeral0. Instance types that support two or more instance store volumes have ephemeral0, ephemeral1, and so on. Instance store pricing Instance store volumes are included as part of the instance’s usage cost. The data on an instance store volume persists even if the instance is rebooted. However, the data does not persist if the instance is stopped, hibernated, or terminated. When the instance is stopped, hibernated, or terminated, every block of the instance store volume is cryptographically erased. Therefore, do not rely on instance store volumes for valuable, long-term data. If you need to retain the data stored on an instance store volume beyond the lifetime of the instance, you need to manually copy that data to more persistent storage, such as an Amazon EBS volume, an Amazon S3 bucket, or an Amazon EFS file system. There are some events that can result in your data not persisting throughout the lifetime of the instance. The following table indicates whether data on instance store volumes is persisted during specific events, for both virtualized and bare metal instances1. References: Amazon EC2 instance store - Amazon Elastic Compute Cloud

Amazon Simple Queue Service (Amazon SQS) is a fully managed message queuing service that lets you send, store, and receive messages between software components at any volume, without losing messages or requiring other services to be available1. Amazon SQS is designed to provide a simple and reliable way for customers to decouple and connect components (microservices) together using queues2. Queues are an important mechanism for providing fault tolerance and scalability in distributed systems, and help decouple different parts of your application3. The other options are not AWS services that are used specifically for sending messages between applications

 Amazon EFS is a fully managed service that provides scalable and elastic file storage for multiple Amazon EC2 instances. Amazon EFS supports the Network File System (NFS) protocol, which allows multiple EC2 instances to access the same file system concurrently. You can learn more about Amazon EFS from this webpage or this digital course.

AWS KMS is the service that is used to provide encryption for Amazon EBS. AWS KMS is a managed service that enables you to easily create and control the encryption keys used to encrypt your data. Amazon EBS uses AWS KMS to encrypt and decrypt your EBS volumes and snapshots. You can choose to use either the default AWS managed CMK or your own customer managed CMK for encryption. AWS KMS also provides features such as key rotation, audit logging, and access control policies to help you manage your encryption keys and protect your data12. The other services are not used to provide encryption for Amazon EBS. AWS Certificate Manager is a service that lets you provision, manage, and deploy public and private SSL/TLS certificates for use with AWS services and your internal connected resources3. AWS Systems Manager is a service that provides a unified user interface to view and manage your AWS resources, automate common operational tasks, and apply compliance policies4. AWS Config is a service that enables you to assess, audit, and evaluate the configurations of your AWS resources. References: Amazon EBS encryption, AWS Key Management Service, AWS Certificate Manager, AWS Systems Manager, [AWS Config]