Amazon Web Services or AWS is one of the leading on-demand cloud platforms. Launched in 2002, AWS has widened its cloud computing services over the years, and today, it has 32 percent of shares in the cloud market.
With more and more businesses shifting to the cloud and moving away from the traditional in-house IT infrastructure, the demand for cloud computing services is also increasing tremendously. As a result, many cloud service providers, including AWS, are actively looking to hire expert cloud professionals.
In case you are interested in building a career in the cloud industry, you may be thinking about appearing in cloud engineer job interviews. Since AWS is the most popular cloud computing service provider, pursuing a career in AWS can be a really good idea.
Nonetheless, if you are interested in becoming an AWS Cloud Engineer, this article can be of great help. Here, we have discussed the most frequently asked AWS interview questions along with their appropriate and detailed answers.
So, let’s not waste any time and get started!
Top AWS Interview Questions and Answers
We have divided the curated list of AWS interview questions into three different levels, namely Basic, Intermediate, and Advanced.
Basic-Level AWS Interview Questions
1. What do you understand by AWS?
Answer: AWS is a cloud storage platform that provides various computing services such as networking services, cloud services, and storage services. It provides affordable and efficient cloud computing solutions that are also easily scalable.
AWS provides three cloud computing models described as below:
- Infrastructure as a Service (IaaS): IaaS is the basic layer of infrastructure for instant computing in cloud IT.
- Platform as a Service (PaaS): PaaS is a model for cloud computing that provides an environment for the deployment of applications in the cloud.
- Software as a Service (SaaS): SaaS is a model that allows applications to be delivered over the internet.
2. What services does AWS provide?
Answer: The following are some popular services that AWS provd:
- AWS Lambda: AWS Lambda is a highly efficient computing platform that provides computing resources required to run a code or application.
- Amazon EC2: Amazon EC2 is an abbreviation for Amazon Elastic Compute Cloud. It provides a secure environment that provides resizable cloud computing capacity.
- AWS Elastic Beanstalk: It is a platform that facilitates the efficient deployment of applications.
- Amazon VPC: Amazon VPC allows users to create a private network with complete access and command over it.
- Amazon Route 53: Amazon Route 53 provides a reliable and pocket-friendly way of routing.
- Amazon S3: Amazon S3 is a platform that provides cloud storage space.
- Amazon Glacier: It is another storage service that is affordable and suitable for long-term storage.
3. What is auto scaling?
Answer: Auto scaling in cloud computing refers to the automatic increase or decrease of the resource capacity according to the demand.
AWS offers auto scaling of applications and automates the scaling of resources by optimizing the cost and availability. AWS auto scaling is quite efficient and powerful as it allows users to create scale plans. Auto scaling in AWS lets users maintain the optimality of the application’s performance even in the case of non-uniform loads and demands by monitoring the performance continuously.
AWS auto scaling also lets users track and configure resources to enhance the performance of applications hosted on AWS. The scaling offered by AWS involves both predictive and dynamic scaling to adjust the computing power. Users can either choose the predefined strategies for scaling or they can create their own customized strategies for scaling and ensure optimal utilization of resources.
4. Explain geo-targeting in CloudFront?
Answer: The Amazon CloudFront provides geo-targeting that can locate the user’s origin from where the content is being accessed, thereby facilitating the creation of personalized content according to the location of the target audiences. The geographic location information is received by the servers of Amazon CloudFront in an HTTP header. This allows a customized content delivery as per the demands of the users that belongs to specific locations around the world, without changing the URL.
User’s country is detected by geo-targeting and then the code of their country is sent to the servers located in your region, and that’s how you can target the viewer of specific geographic locations. This feature is available in the Amazon CloudFront without any extra charges, and you can choose which headers you want to forward to the servers of your origin.
5. Differentiate between EC2 and S3?
Answer: The following table highlights the differences between EC2 and S3:
|It’s a cloud-based web service.||It’s a data storage service.|
|It hosts your applications over the cloud.||It stores and manages the data for the applications.|
|EC2 is a machine that is based on the cloud.||It is not a machine, instead, it’s a REST interface.|
|EC2 can be set up as per the requirements of a user, and it is capable of running many utilities like Apache, PHP, LINUX, WINDOWS, and even databases.||S3 allows users to store large binary data and other large data objects, and it can even work along with EC2.|
6. Explain AWS Lambda?
Lambda enables the virtual execution of any type of program or server-side services without any management or provisioning. It is affordable as the users only pay for the time taken by the program to compute. Users don’t have to pay when a program is not running on AWS Lambda, unlike its counterpart Amazon EC2, which is metered per hour.
It also supports automatic scaling, which means that while a program gets executed, Lambda will meter the number of requests up to thousands of requests per second without any delay.
7. Explain the Amazon EBS Volumes.
Answer: Elastic Block Stores or EBS is a storage service that is used to connect the instances like EC2. Amazon EBS Volume is a highly durable and flexible block-level storage device that once connects an instance and works as a physical hard drive. The storage size can be increased dynamically according to the needs of the user.
EBS Volumes are highly efficient and useful for storing the type of data that needs frequent modification. Multiple EBS Volumes can be connected to a single instance using Multi-Attach, depending on the type of instances.
Amazon EBS also provides a data encryption feature. All volumes can be encrypted and used to meet the vast range of data encryption requirements.
8. What is the need for subnetting?
Answer: Subnetting means creating sub-parts of a single large network to serve security purposes and increase the overall efficiency of the network. This makes it easier to maintain the smaller networks and also provides better security to all the sub-networks. If there is subnetting in a network, it will avoid any unnecessary routing of the network traffic and the traffic would have to travel a much shorter distance.
Data packets received from one network to another, are first sorted and then routed directly to the desired destination network through subnet, hence this reduces the unnecessary time taken for routing data.
In a network, there could be a huge number of connected devices, thus making it time-consuming for the data to reach the desired device. So, in such a case, subnetting of the network plays a very crucial role. With subnetting, IP addresses can be narrowed down to devices in a small range so that the data can route directly in less time.
9. What do you understand by EIP?
Answer: Elastic IP (EIP) is a very important aspect in dynamic cloud computing that allows communication between various instances and the internet. This comes in handy due to the fact that EIP is static and does not change after the termination of an instance. Public IP gets released as soon as an instance is re-launched, whereas an EIP remains the same even after the termination or start of an instance.
EIP makes the infrastructure simple and adjusts the instances and their communication with the public internet according to the changing environments. EIP is basically a combination of both public and static IP addresses. AWS EIP is an excellent solution for dynamic cloud computing as its static, as well as public states, allow the advertisement of content in a dynamic environment.
10. Why should one use Amazon EBS volumes over its other competitors?
Answer: Amazon EBS Volumes provide a wide range of benefits with some of them as follows:
- Data availability: EBS volumes have their own availability zones depending on which they get attached to the instances. Multiple volumes can connect to a single instance if they are available in the availability zone. Once attached, it behaves like a physical hard drive.
- Data Persistence: EBS offers non-volatile storage. Connected EBS volumes can be disconnected from a running instance without the fear of losing data.
- Data Encryption: EBS also supports data encryption. Every volume can be encrypted easily with the Amazon EBS encryption feature. It uses AES-256 or 256-bit Advanced Encryption Standard algorithms for encryption.
- Snapshots: Amazon EBS Volume lets users create backups of the instances. Instances need not be connected to any volume for taking snapshots. Snapshots taken of an availability zone remain inside the same zone.
11. What is Cloudwatch?
Answer: AWS Cloudwatch is a tool to monitor applications and manage their resources. This allows you to have a metric report of the performance of your applications in real-time. Also, it allows you to track other AWS services in the form of stats and graphical reports, thus assisting you to configure all your AWS services within the console.
AWS provides 2 types of Cloudwatch:
Basic monitoring: Basic monitoring is available by default in AWS Cloudwatch on the launch of an instance. In general, the Cloudwatch requires 5 minutes to collect monitoring data.
Detailed monitoring: To get detailed monitoring of the instances, you have to enable it explicitly. Detailed monitoring Cloudwatch takes up a period of 1 minute for collecting data.
12. What do you understand by Amazon EC2?
Answer: Amazon EC2 or Amazon Elastic Compute Cloud is a cloud computing platform that provides a secure computing environment. It offers cloud computing resources that users can easily scale as per their needs. The term elastic represents the flexibility that EC2 provides for creating or terminating instances.
Amazon EC2 lets users choose the type of processor, storage, networking system, and OS of their choice. According to Amazon, Amazon EC2 provides the fastest processors among all the cloud computing platforms.
13. What do you know about Amazon VPC?
Answer: Amazon VPC or Virtual Private Cloud enables you to create your own personal virtual cloud network. It provides you the privilege to choose your own IP address, create personal subnets, and configure routing networks. Multiple users in a single cloud can create private networks by allocating their private IP addresses.
VPC is free of cost, but if someone wants to use any Virtual Private Network or VPN, they have to pay for each of them. It is quite easy to create VPC by using the command-line interface provided by Amazon or AWS Management Console. VPC provides an easy setup so that users can spend more time building projects rather than setting up the environment for them.
Additionally, you can store your data on Amazon S3 and manage its access permissions so that only those who are inside your VPC can access the data. Amazon VPC also allows inspection of traffic to provide better security.
14. What is Amazon S3?
Answer: Amazon Simple Storage Service (S3) is a data storage service for applications hosted on the cloud. It is not a machine, instead, it is a REST interface. S3 allows you to store large binary data and other large data objects, and it can even work with EC2. Moreover, S3 is capable of storing and retrieving data of any size, and also ensures the security of the data along with the data backup and restore options.
S3 is robust and capable to manage permissions, cost, privacy, and data access quite efficiently. Moreover, S3 objects can also run big data analytics with the services provided by AWS S3.
The Amazon S3 is a durable service with a durability of approximately 99.99%, which makes it highly reliable for the security of data and metadata stored in it.
15. Can you cast S3 with EC2 instances? If yes, explain how?
Answer: Yes, if root approaches having native storage backup are used, then S3 instances can be cast-off with the EC2 instances. The S3 services by Amazon provide a developer with the capability to use storage structures that have highly scalable and reliable operations. However, if you want to use these operations with EC2 instances, there are some tools that can help you with that.
16. What do you know about Amazon DynamoDB?
Answer: Amazon DynamoDB is a cloud database based on NoSQL that can operate trillions of user requests per day. It is a robust database that can deliver impressive performance at any scale. Amazon DynamoDB has an in-built backup and security for the applications along with caching in-memory.
Several companies that have large-scale applications are using DynamoDB for handling the workloads of their database due to its high reliability and scalability. DynamoDB is a self-handled service that just needs you to add your application and then leave everything to it. There is no need to manage servers or install any software, DynamoDB can handle everything on its own.
17. Differentiate between terminating and stopping an instance?
- Terminating an instance: Termination is in total contrast with stopping. Once you terminate your instance, all the instances connected to your EBS Volumes instance get deleted, no matter if you have saved them or not. This process can not be undone and you can not access your instance again.
- Stopping an instance: When you stop an instance, it simply means that you are applying a temporary shut down. EBS volumes still remain intact to the instances. Stopping does not result in any kind of data loss. It means that once you restart your instance, you can resume it from the point where it last left.
18. How do on-demand instances differ from spot instances?
- Spot Instances: These instances are unreserved and extra instances, which are unused. They can only be purchased through bidding. Spot instances become available for usage only if the price exceeds the base price. There is no assurance from AWS on the availability of spot instances. They are cheaper and pocket-friendly as compared to on-demand instances.
- On-demand instances: These instances are only available depending on the needs of the users and have a fixed price which one has to pay per hour. It is easy to delete on-demand instances once there is no need for them. Unlike spot instances, you do not have to bid for them.
19. Explain Amazon S3 Glacier?
Answer: Amazon S3 Glacier is a pocket-friendly cloud storage service provided by AWS. It is known for its high durability and long-term backup. The Amazon S3 Glacier offers storage at a price as low as $1 per TB of data per month.
To meet the requirements of all kinds of users at a low cost, Amazon S3 Glacier avails three types of retrievals:
- Expedited: These retrievals provide the fastest returns, it just takes 1 to 5 minutes.
- Standard: These retrievals are ideal for less time requiring data, like backup and media editing. They take 3-4 hours in returning the data.
- Bulk: These retrievals are the cheapest among all. They work best for large chunks of data and usually take 5-12 hours in returning the data.
20. What do you understand by Direct Connect?
Answer: Direct Connect by AWS provides a network connection between your internal network and AWS with the help of an Ethernet cable. This service helps to reduce the costs for the network and also offers high bandwidth without an internet connection. Virtual interfaces can also be partitioned using this dedicated network connection using VLANs.
Additionally, Direct Connect makes it possible to access public resources, like S3 instances, and private resources, like EC2 objects. To access the private resources, you need to use private IP space. So, if the separation of the network is between the private and public spaces, you can use the same connection to access both kinds of resources.
Intermediate-Level AWS Interview Questions
21. Differentiate Amazon RDS and Amazon DynamoDB?
Answer: Although both the services provide management of databases, Amazon RDS and Amazon DynamoDB are still different from each other.
- Amazon RDS: It is an AWS service for managing relational databases. The operations for the relational databases are handled automatically by AWS RDS. However, Amazon RDS is suitable for working with structured data.
- Amazon DynamoDB: It is a cloud database based on NoSQL that can operate trillions of user requests per day. It is a high-performance and durable database that can give very high performance at any scale. Amazon DynamoDB offers in-built backup and security features for the applications along with caching in-memory.
22. Mention some of the ways to log in to the cloud console.
Answer: Some of the popular tools to log in to the cloud console are as follows:
- Eclipse: The Java IDE Eclipse has a plug-in that is actually a toolkit to access and use AWS keys. This plug-in is entirely open-source that helps the developers to access their AWS console right from the IDE itself.
- AWS SDK: The AWS SDK API is also an amazing solution to get access to your cloud console.
- AWS CLI: AWS CLI or command-line interface is a tool that can help users to access multiple AWS services.
23. How elasticity is different from scalability?
Elasticity in cloud computing is simply upgrading and degrading the physical hardware resources as soon as the load varies. When there is an increase in the demand, the resources are increased, and when the workload decreases, the resources are taken down.
Scalability in terms of cloud computing is somewhat similar to elasticity, but it differs by the fact that on the increase of the demand in workload, the load can be accommodated by an increase in the number of hardware resources or increasing the processing nodes.
Both elasticity and scalability are dependent on the requirements and can rise or shrink accordingly, thereby providing a high performance for the applications.
24. Explain the steps to migrate a domain name that already exists to Amazon Route 53 without interrupting the web traffic.
Follow the below-given steps to migrate an existing domain name to Amazon Route 53:
- STEP 1: Get the DNS records of the domain name registered already from the extant DNS provider. The DNS records are usually available in a zone file format.
- STEP 2: To store the DNS records, you need to create a hosted zone either by using the Route 53 console or the web-services interface.
- STEP3: Now, send your information to the registrar to continue the migration process. When the registrar propagates the new name server, the DNS queries will be transferred.
25. What do you know about AWS CloudFormation?
Answer: AWS CloudFormation service helps developers manage all other AWS services from one place. This avoids the management hustle for developers and they can concentrate more on application development than resource management.
CloudFormation creates a template that contains all the details of the required resources of a particular project along with its properties. Also, it is quite easy to delete the template. Moreover, CloudForamtion saves users from the replication process. Instead of replicating all the resources, users can simply create a template and then replicate it as a single unit.
26. Can you use the standby DB instances with primary DB instances while executing DB instances as a Multi-AZ deployment?
Answer: The answer to this is a no. Since standby DB instances only work if primary instances crash, therefore they cannot work hand in hand.
27. What do you understand about SNS?
Answer: SNS or Simple Notification Service is a web service that acts as a messenger i.e. it sends all the messages and notifications directly to the user from the cloud.
SNS contains two kinds of clients:
The Publisher is the server that sends messages for the user. The messages can be anything, such as a simple notification or a warning. Also, these messages are received on one of the server-supported protocols such as HTTP, Lamba, etc.
28. Define SQS?
Answer: SQS is an abbreviation for Simple Queue Service. It establishes messaging communication between applications. It is a highly efficient and secure service provided by AWS. SQS can deliver messages across multiple AWS platforms such as Lambda, EC2, etc.
SQS provides Standard queues and FIFO queues. Standard queue ensures that every application gets the message at least once. On the other hand, FIFO (First In First Out) makes sure that messages execute in the same sending order.
29. What is the work of Amazon Redshift?
Answer: Amazon Redshift is a cloud management service. Its functions include monitoring the data, provisioning the storage capacity, and uploading the data to the redshift engine.
Amazon Redshift has a collection of nodes, among which, one is a root node or leader node and others are computing nodes. The strength of the computing nodes depends on how large your data is and how many queries you have for the execution.
It also enables users to create backups either manually or automatically. If a user wishes to restore data from an existing snapshot, they need to create a new cluster to which Redshift will import the data.
30. Define IAM.
Answer: IAM stands for Identity Access Management and it provides security while accessing other AWS services. It enables you to create AWS groups and lets you decide whether AWS services will be accessible by them.
IAM is free of cost, which means that you do not have to pay extra charges for using it. You will only be paying for other AWS services you are using.
31. If one of the resources fails to be created by Amazon OpsWorks, then what will happen?
Answer: When one of the resources fails to be created successfully in the stack by Amazon OpsWorks, all the other successfully created resources get deleted automatically till the point of the error. This process is an Automatic Rollback on error.
The basic principle on which the Automatic Rollback feature works is that either the stack is completely created or does not get created at all. This also ensures that there is no error-containing resource in the stack.
32. Is there any default storage class with which S3 comes?
Answer: Yes, there is always a standard class in every storage service. Standard Class is the default storage class provided by S3.
33. How will you define KMS?
Answer: Amazon Key Management Service or Amazon KMS is an efficient security service that protects your encrypted keys. It allows users to manage their keys for encrypted data across a whole wide variety of services provided by AWS.
AWS gives total access to your keys to you by determining several admin-friendly usage permissions. Alongside this, it also makes sure the physical protection of these keys.
34. How will you state the difference between AWS CloudFormation and AWS OpsWorks?
Answer: Both the AWS CloudFormation and AWS OpsWorks are management services provided by AWS. However, they differ in some aspects that are as follows:
- AWS CloudFormation is a service that enables developers to manage all other AWS services from one single place. On the other hand, AWS OpsWorks widely focuses on providing a secure DevOps experience to its developers.
- Compared to AWS CloudFormation, AWS OpsWorks serves fewer AWS resources, which is a major drawback of it.
35. Does Standby RDS get launched in the same availability zone in which primary is launched?
Answer: No, Standby RDS does not get launched in the same availability zone as primary. Standby instances work as a backup for primary instances. When primary instances fail, they come into work. So they need to be stored in separate availability zones in order to remain independent from the primary instances.
Advanced-Level AWS Interview Questions
36. Define AWS CloudTrail.
Answer: AWS CloudTrail is a cloud governance service that enables you to govern your cloud services and monitor your activities. Also, it provides your event history, which is impacted by your daily AWS activities.
Some of the key benefits offered by AWS CloudTrail are as follows:
- Simplified compliance
- Visibility into resource and activity
- Security analysis and troubleshooting
- Security automation
37. Give a brief overview of Amazon Elastic Beanstalk.
You just have to upload your program on Elastic Beanstalk, and it will automatically manage and deploy your project on the servers. You never lose control over your application and can access all the resources used in your project anytime you want.
38. Which AWS storage service is best for data archiving and low cost?
Answer: Amazon S3 Glacier is extremely pocket-friendly and offers efficient services. It also provides data archiving, which makes it highly popular in the industry.
39. Define Elastic LoadBalancing.
Answer: Elastic LoadBalancing is another cloud service provided by Amazon for managing the load of your application’s traffic. It is highly efficient in handling incoming traffic from various targets such as IP addresses and other virtual functions.
The following are the types of load balancers that the Elastic LoadBalancing offer:
- Network Load Balancer
- Application Load Balancer
- Gateway Load Balancer
- Classic Load Balancer
40. What is the use of Network Load Balancer?
Answer: Network Load Balancers are ideal for managing the load of various protocols such as ITP and UDP. As compared to other load balancers, Network Load Balancers are highly efficient. They are capable of managing billions of server requests per second.
41. State the benefits of Elastic Beanstalk.
Answer: Some of the benefits that Elastic Beanstalk offers are as follows:
- Easy application deployment
- Enables autoscaling
- Increases productivity of the developer
- Various customization options
42. What type of subnet would you prefer to start if you have a VPC with private and public subnets?
Answer: Private subnets are ideal for launching in database servers. Since the users who own the corresponding applications cannot access private subnets, they are the most eligible for backend services.
43. What is the use of Classic Load Balancer?
Answer: Classic Load Balancer is the most primitive and simplest load balancer among all. It balances the load between various EC2 instances. Unlike other load balancers, it can function at the request level and the connection level.
44. State the layers available in cloud computing.
Answer: The following are the layers available in cloud computing:
- Infrastructure as a Service (IaaS): Iaas is the basic layer of infrastructure for instant computing in cloud IT. It facilitates services such as storage resources and provides access to networking tools over the internet.
- Platform as a Service (PaaS): PaaS is a cloud computing model that provides an environment for the deployment of applications in the cloud. It provides services and stacks for the deployment of applications. The platform it provides gives services such as databases and operating systems.
- Software as a Service(SaaS): SaaS is a computing platform that makes it possible to deliver applications via the internet. In other words, SaaS allows users to access applications through web browsers.
45. What are the different storage classes provided by S3?
Answer: Following are the different storage classes provided by S3:
- Standard frequency accessed
- One-zone infrequency accessed
- RRS – reduced redundancy storage
- Standard infrequency accessed
46. Define Gateway Load Balancer.
Answer: Gateway Load Balancer enables you to provide load balancing to third-party networking applications. Its transparency to the source as well as to the destination makes it the most suitable choice for balancing the load of third-party applications.
47. Explain the terms RTO and RPO?
Answer: In any business, there are always the chances of having some critical situations like system failure or loss of data. In such cases, the two most crucial parameters are RTO and RPO that are concerned with the protection and recovery of your data.
RTO (Recovery Time Objective) is basically the maximum amount of time that can be given for the recovery in case of an interruption in the service.
RPO (Recovery Point Objective) is the data that you can lose in case a critical situation occurs.
48. State the metrics retention period in Cloudwatch.
Answer: The metrics retention period in Cloudwatch is as follows:
|Period of Datapoints||Availability|
|60 seconds||3 hours|
|60 seconds||15 days|
|5 minutes||63 days|
|1 hour||455 days|
49. State deployment models for the cloud?
Answer: Models for deployment over the cloud are:
- Public Cloud: This model supports all types of users.
- Private Cloud: It only supports a single organization.
- Hybrid Cloud: Hybrid cloud model supports private networks that are interconnected.
- Community Cloud: This model supports more than one organization connected to a single network.
50. Can you provide any certification to give a boost to your application for this AWS role?
Answer: Possessing a certificate of the tech stack and skills that are required in the job description is always beneficial. This creates a positive impression on the interviewer that you are familiar with the required technology and have an in-depth understanding of the concepts as well as the practical applications. This also boosts up your resume and helps it to stand out, adding immense value to it as well as to your knowledge.
Wrapping it Up
In this article, we discussed the top AWS interview questions. Also, we covered all the aspects of AWS starting from the introduction of AWS and moving towards advanced topics such as cloud computing models, scaling, EC2 & S3 instances, load balancing, and various services provided by AWS.
We certainly hope that the AWS interview questions and answers mentioned above will help you to revise various important AWS concepts that can help you crack your next interview with flying colors.
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