AWS Developer Interview Questions and Answers

(Or)

AWS is a platform to provide secure cloud services, database storage, offerings to compute power, content delivery, and other services to help business level and develop.

PaaS – PaaS stands for Platform as a Service. Here, the service provider provides various services like databases, queues, workflow engines, e-mails, etc. to their customers. The customer can then use these components for building their own applications. The services, availability of resources and data backup are handled by the service provider that helps the customers to focus more on their application’s functionality.

SaaS – SaaS stands for Software as a Service. As the name suggests, here the third-party providers provide end-user applications to their customers with some administrative capability at the application level, such as the ability to create and manage their users. Also some level of customizability is possible such as the customers can use their own corporate logos, colors, etc.

Daas – Desktop as a Service (DaaS) is a desktop virtualization service that is hosted on the cloud, so users can access their virtual desktops and applications wherever they go, using whichever device they need. DaaS is purchased through a subscription and offers a multitenancy environment. With a DaaS, the Virtual Desktop Infrastructure (VDI) is deployed and managed by a service provider, which means that the responsibilities of maintaining security, upgrades, data backup and storage are outsourced to your service provider.

Amazon EBS: Its durable, block-level storage volumes can attached in running Amazon EC2 instance. The Amazon EBS volume persists independently from the running life of an Amazon EC2 instance. After an EBS volume is attached to an instance, you can use it like any other physical hard drive. Amazon EBS encryption feature supports encryption feature.

Amazon EC2 Instance Store: Storage disk that is attached to the host computer is referred to as instance store. The instance storage provides temporary block-level storage for Amazon EC2 instances. The data on an instance store volume persists only during the life of the associated Amazon EC2 instance; if you stop or terminate an instance, any data on instance store volumes is lost.

Amazon S3: Amazon S3 provides access to reliable and inexpensive data storage infrastructure. It is designed to make web-scale computing easier by enabling you to store and retrieve any amount of data, at any time, from within Amazon EC2 or anywhere on the web.

Adding Storage: Every time you launch an instance from an AMI, a root storage device is created for that instance. The root storage device contains all the information necessary to boot the instance. You can specify storage volumes in addition to the root device volume when you create an AMI or launch an instance using block device mapping.

• Stopping and Starting an instance: When an instance is stopped, the instance performs a normal shutdown and then transitions to a stopped state. All of its Amazon EBS volumes remain attached, and you can start the instance again at a later time. You are not charged for additional instance hours while the instance is in a stopped state.
• Terminating an instance: When an instance is terminated, the instance performs a normal shutdown, then the attached Amazon EBS volumes are deleted unless the volume’s deleteOnTermination attribute is set to false. The instance itself is also deleted, and you can’t start the instance again at a later time.

• CC- Cluster Controller
• SC- Storage Controller
• CLC- Cloud Controller
• NC- Node Controller
• Walrus

• It is a cloud web service used for hosting your application
• It is like a huge computer machine which can run either Linux or Windows and can handle application like PHP, Python, Apache or any databases.

S3:

• It is a data storage system where any amount of data can be stored
• It has a REST interface and uses secure HMAC-SHA1 authentication keys.

• Scalability is the ability of a system to increase its hardware resources to handle the increase in demand. It can be done by increasing the hardware specifications or increasing the processing nodes.
• Elasticity is the ability of a system to handle increase in the workload by adding additional hardware resources when the demand increases (same as scaling) but also rolling back the scaled resources, when the resources are no longer needed. This is particularly helpful in Cloud environments, where a pay per use model is followed.

• Amazon RDS is a database management service for relational databases, it manages patching, upgrading, backing up of data etc. of databases for you without your intervention. RDS is a Db management service for structured data only.
• Dynamo DB, on the other hand, is a NoSQL database service, NoSQL deals with unstructured data.
• Redshift, is an entirely different service, it is a data warehouse product and is used in data analysis.