This page contains the collection of AWS Interview Questions and Answers / Frequently Asked Questions (FAQs) under category AWS. These questions are collected from various resources like informative websites, forums, blogs, discussion boards including Wikipedia. These listed questions can surely help in preparing for AWS interview or job.
1) What is Amazon EC2 service?
Ans: EC2 uses Xen virtualization. Each virtual machine, called an “instance”. You can use Amazon EC2 to launch as many or as couple of virtual servers as you need, design security and networking, and manage storage. Amazon EC2 empowers you to scale up or down to handle changes in requirements.
2) What is Amazon Machine Image (AMI)?
Ans: An Amazon Machine Image (AMI) is a template that contains a software configuration (for example, an operating system, an application server, and applications). From an AMI, we launch an instance, which is a copy of the AMI running as a virtual server in the cloud. We can launch multiple instances of an AMI.
3) What is the relation between Instance and AMI?
Ans: We can launch different types of instances from a single AMI. An instance type essentially determines the hardware of the host computer used for your instance. Each instance type offers different compute and memory capabilities.
After we launch an instance, it looks like a traditional host, and we can interact with it as we would any computer. We have complete control of our instances; we can use sudo to run commands that require root privileges.
4) What are the Security Best Practices for Amazon EC2?
Ans: There are several best practices for secure Amazon EC2. Following are few of them.
Use AWS Identity and Access Management (IAM) to control access to your AWS resources.
Restrict access by only allowing trusted hosts or networks to access ports on your instance.
Review the rules in your security groups regularly, and ensure that you apply the principle of least
Privilege — only open up permissions that you require.
Disable password-based logins for instances launched from your AMI. Passwords can be found or cracked, and are a security risk.
5) Explain Stopping, Starting, and Terminating an Amazon EC2 instance?
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.
6) How to use Amazon SQS?
Ans: Amazon SQS is a message passing mechanism that is used for communication between different connectors that are connected with each other. It also acts as a communicator between various components of Amazon. It keeps all the different functional components together. This functionality helps different components to be loosely coupled, and provide an architecture that is more failure resilient system.
7) How buffer is used in Amazon web services?
Ans: Buffer is used to make the system more resilient to burst of traffic or load by synchronizing different component. The components always receive and process the requests in unbalanced way. Buffer keeps the balance between different components and makes them work at the same speed to provide faster services.
8) How does cloud computing provides on-demand functionality?
Ans: Cloud computing is a metaphor used for internet. It provides on-demand access to virtualized IT resources that can be shared by others or subscribed by you. It provides an easy way to provide configurable resources by taking it from a shared pool. The pool consists of networks, servers, storage, applications and services.
9) What is the difference between scalability and elasticity?
Ans: Scalability is a characteristic of cloud computing through which increasing workload can be handled by increasing in proportion the amount of resource capacity. It allows the architecture to provide on demand resources if the requirement is being raised by the traffic. Whereas, elasticity is being one of the characteristic provide the concept of commissioning and decommissioning of large amount of resource capacity dynamically. It is measured by the speed by which the resources are coming on demand and the usage of the resources.
10) What are the different layers of cloud computing?
Ans: Cloud computing consists of 3 layers in the hierarchy and these are as follows:
1. Infrastructure as a Service (IaaS) provides cloud infrastructure in terms of hardware like memory, processor speed etc.
2. Platform as a Service (PaaS) provides cloud application platform for the developers.
3. Software as a Service (SaaS) provides cloud applications which are used by the user directly without installing anything on the system. The application remains on the cloud and it can be saved and edited in there only.
11) How to secure your data for transport in cloud?
Ans: Cloud computing provides very good and easy to use feature to an organization, but at the same time it brings lots of question that how secure is the data, which has to be transported from one place to another in cloud. So, to make sure it remains secure when it moves from point A to point B in cloud, check that there is no data leak with the encryption key implemented with the data you sending.