40 AWS Interview Questions and Answers for 2023
Advertise your job effectively
Create an effective job advertisement to get the right candidates for interviews. Include the following in it:
Introduce your company with general facts, however, ensure you make the introduction exciting. Talk about the growth opportunities you offer. Describe the organizational culture, work environment, and professional development opportunities. Finally, talk about your compensation and benefits policies.
Job descriptions for Amazon Web Services (AWS) developers
Explain the nature of the work that an AWS developer will have in your organization. Provide details of your current development infrastructure and technology stacks. Specify what you use, e.g., IaaS (Infrastructure-as-a-Service) or PaaS (Platform-as-a-Service).
Describe what your objectives are, e.g., improved reliability, better scalability, etc. Talk about any challenges that you want to address, e.g., inadequate monitoring, inefficient deployment, etc. Explain how the contribution of the AWS developer will help your organization to succeed.
Roles and responsibilities of an AWS developer
You need an AWS developer to take up the following responsibilities:
- Understanding the current IT infrastructure and suggesting improvements;
- Defining and documenting the strategies for infrastructure maintenance and application deployment;
- Documenting best practices concerning application deployment and infrastructure maintenance;
- Migrating IT infrastructure if applicable;
- Establishing a monitoring set-up;
- Defining strategies for service capacity planning;
- Implementing the CI (Continuous Integration)/CD (Continuous Delivery) pipelines for applications using the AWS CI/CD stack;
- Creating Infrastructure-as-code where applicable;
- Communicating effectively with the larger team and reporting the status of work.
Skills and competencies that you need in an AWS developer
You need an AWS developer with a degree in computer science, information technology, or related subjects. Furthermore, they need the following skills:
- In-depth skills in core AWS services and the AWS ecosystem;
- Unix/Linux administration experience;
- Experience with Docker and Kubernetes;
- Experience with ECS, EKS, etc.;
- Good knowledge of popular RDBMSs (Relational Database Management Systems) like MySQL, PostgreSQL, etc.;
- Knowledge of popular NoSQL database services like MongoDB, Cassandra, etc.;
- Experience in developing REST APIs and AWS SDK wrapper libraries;
- Sound knowledge of security best practices, processes, and tools;
- Good knowledge of monitoring solutions like CloudWatch;
- Experience in large-scale system design;
- In-depth experience in troubleshooting distributed systems;
- Knowledge of writing IaC (Infrastructure as Code) using CloudFormation or Terraform;
- Cloud-native application development and maintenance experience;
- Good knowledge of Serverless approaches using AWS Lambda.
You need an AWS developer to have the following competencies:
- Passion for excellence;
- Communication skills;
- Problem-solving skills;
- The ability to see the bigger picture.
AWS interview questions for junior developers
Use the following interview questions when evaluating junior AWS programmers:
Question 1: What are the various kinds of cloud computing products AWS offer?
Answer: AWS offers the following 3 kinds of cloud computing products:
- Computing: These concern cloud computing service resources. A few examples are Auto-Scaling, Elastic Compute Cloud EC2, Lightsail, AWS Elastic Beanstalk, and AWS lambda.
- Storage: AWS offers several products concerning storage, e.g., S3 (Amazon Simple Storage Service) which comes with various storage classes and a default storage class, Elastic File System, Elastic Block Storage, and Amazon Glacier.
- Networking: AWS offers products in the networking space. A few examples are VPC (Virtual Private Cloud), Route53 (DNS web service), and Amazon CloudFront.
Question 2: Explain the function of an AMI in the context of AWS cloud architecture.
Answer: AMI (Amazon Machine Image) is a template used in AWS. An AMI contains information that helps you to launch instances. These instances will be a copy of the AMI, and the instance will run as a virtual server on the AWS cloud.
The information in an AMI concerns the operating system (OS), applications, and the application server. You can use different AMIs to launch multiple instances at the same time.
Question 3: What does the Auto-Scaling function in AWS resources do?
Answer: The Auto-Scaling function in AWS helps with provisioning and launching new instances. This function recognizes the demand for computing resources. Users of AWS can easily increase or decrease the computing resource capacity according to their needs, thanks to the Auto-Scaling function of AWS.
Question 4: Explain the utility of an Elastic IP address in AWS resources.
Answer: An “Elastic IP address” in AWS is a static IP address. It’s a public IPv4 address, therefore, others can reach it over the Internet. AWS offers this feature for dynamic cloud computing. Every AWS account comes with an Elastic IP address.
Sometimes, you might have a failure in an instance due to some reasons. You can mask this failure by using the Elastic IP address allocated to you. You can rapidly map the address to another instance in your AWS account, which masks the failure in the other instance.
You can also specify the Elastic IP address in a DNS record for your domain. This will make the domain point to the instance you prefer.
Question 5: What is a VPC in AWS?
Answer: A VPC (Virtual Private Cloud) is a private cloud that’s hosted within a public cloud. The cloud services provider secures and isolates a VPC within a public cloud. AWS is one of the leading providers of VPC to launch AWS resources in a virtual network.
A VPC allows an organization to have dedicated computing resources that are available on a private cloud. However, the fact that a VPC is hosted within a public cloud allows organizations to buy computing resources easily on demand. That makes VPCs scalable.
A VPC allows organizations to have their IP address range, subnet, security groups, and Internet gateways. VPCs make it easier to connect private cloud to hybrid cloud and on-premises infrastructure, therefore they are popular. The AWS VPC offering provides security, ease of use, scalability, performance, and robust tooling support.
Question 6: Explain the utility of Amazon CloudFront, and briefly explain how to use it.
Answer: Amazon CloudFront is a global CDN (Content Delivery Network) offered by AWS. It delivers data to users with speed and security. CloudFront offers low latency.
You need to take the following steps to use it:
- Create a CloudFormation template in JSON or YAML format.
- Save the code in an S3 bucket so that you have a code repository.
- Use AWS CloudFormation to call the bucket. This creates a new stack on the template.
With this, CloudFormation reads the file. It understands the services that need to be executed. It calls them along with details like the relationships with the services.
Question 7: What is Amazon CloudWatch?
Answer: Amazon CloudWatch is a service from AWS to monitor all the AWS resources and applications that a user runs. CloudWatch monitors them in real time. It collects metrics that measure resource utilization, furthermore, CloudWatch monitors applications.
You can use CloudWatch to capture client connection information from your load balancer. Furthermore, you can use it to monitor the input and output (I/O) operations of database instances. CloudWatch can send alerts to your operations team.
Question 8: What is an Amazon EBS volume?
Answer: An Amazon EBS volume is a durable, block-level storage device offered by AWS. You can attach EBS volumes to your instances. Subsequently, you can just use it as a physical hard drive.
You can use EBS volumes as the primary storage option for data that needs updates often. EBS volumes are flexible, and you can use them for throughput-intensive applications. You can attach more than one EBS volume to one instance.
Question 9: Explain the differences between Amazon EC2 and Amazon S3.
Answer: The differences between EC2 and S3 are as follows:
- EC2 is a cloud web service, whereas, S3 is a data storage system.
- You use EC2 to host web applications. On the other hand, you use S3 to store any amount of data.
- EC2 is effectively a computer, whereas, S3 is a REST interface.
- EC2 supports operating systems like Unix and Windows. It supports programming languages like Python, PHP, etc., furthermore, it supports various databases. The scope of S3 is storage only. S3 uses HMAC-SHA1 authentication keys.
Question 10: Which AWS storage solution offers low pricing?
Answer: Amazon Glacier is a storage service offered by AWS that offers low pricing. It’s a good choice for purposes like data archival and backup. AWS has designed the pricing for Amazon Glacier in a way that your costs reduce the longer you store data on it.
Question 11: What are the differences between a region and an availability zone in AWS?
Answer: Regions in the context of AWS are different geographical regions, e.g., United States-West. However, an availability zone is a part of a region. It is a data center with servers, switches, firewalls, etc. Availability zones are isolated zones. These zones or data centers can replicate themselves if there’s a need.
Question 12: What is a “Subnet” in AWS?
Answer: A “Subnet” in the context of AWS is applicable for a VPC. These are private clouds that are hosted within a public cloud. VPCs are hosted in a secure and isolated manner. A subnet in AWS refers to a large set of IP addresses that are divided into chunks. One VPC in AWS can have 200 subnets.
Question 13: How many Elastic IP addresses can you have in one AWS account?
Answer: One AWS account allows you to create 5 Elastic IP addresses per region.
Question 14: What is AWS Lambda?
Answer: AWS Lambda is a Serverless computing platform offered by AWS. This event-driven compute service runs your application code without you managing servers. The Lambda function runs your code only when you need it, and you need to pay only when your code runs.
You don’t need to provide and manage servers when you use AWS Lambda. AWS Lambda scales automatically. You can run any type of application or backend services, and you don’t need to spend effort on server administration.
Question 15: Explain the functions of AWS CloudTrail.
Answer: AWS CloudTrail is a service offered by AWS. This AWS service enables AWS users to implement governance, compliance, operational auditing, and risk auditing of their AWS accounts. Users can set up CloudTrail to log and continuously monitor account activities.
AWS CloudTrail can retain the account activities across the AWS infrastructure of an organization. CloudTrail provides the event history of AWS account activities. It can do that for actions taken through the AWS Management Console, AWS SDKs (Software Development Kits), command-line tools, and other AWS cloud services. CloudTrail can log and track API calls too.
You can use this event history for security analysis and tracking changes. These event histories also help with troubleshooting.
Question 16: Provide examples of AWS DevOps tools.
Answer: The following are a few examples of AWS DevOps tools:
- AWS CodePipeline: You can use it for managing software release workflows. AWS CodePipeline is a CI (Continuous Integration) and CD (Continuous Delivery) service. It builds, tests, and deploys the code every time there’s a code change.
- AWS CodeBuild: This tool supports building and testing code. AWS CodeBuild is a fully managed build service. It compiles source code and tests it. AWS CodeBuild creates software packages that are ready for deployment.
- AWS CodeDeploy: This tool supports automated code deployment. AWS CodeDeploy automates the deployment of code to Amazon EC2 instances. It can automate the deployment of code to on-premises servers too.
Question 17: Provide examples of a few AWS services.
Answer: A key advantage of using the AWS cloud computing platform is the wide range of AWS cloud services available. A few examples are as follows:
- Analytics: Amazon Athena and Amazon CloudSearch are just a few examples of AWS Analytics services.
- Application integration: Amazon AppFlow is useful for the no-code integration of SaaS apps. Amazon MQ is a managed message broker service.
- Compute: Amazon EC2, AWS Elastic Beanstalk, and AWS Lambda are a few examples.
- Databases: Amazon Aurora is an RDBMS (Relational Database Management Service) offered by AWS. AWS offers Amazon DynamoDB, a managed NoSQL database. Amazon RDS is the managed RDBMS service from AWS for MySQL, PostgreSQL, etc.
- Networking: Amazon VPC (Virtual Private Cloud) is a VPC service from AWS. A VPC is a private cloud that’s securely hosted and isolated within a public cloud. Amazon CloudFront is the global CDN (Content Delivery Network) from AWS.
Question 18: What is AWS IAM (Identity and Access Management)?
Answer: AWS IAM (Identity and Access Management) is a key feature of AWS. This feature enables you to manage access to AWS services and resources securely. It enables you to create users and groups, and you can assign specific permission to them. You can also control access to sensitive information using IAM. Your AWS account includes IAM without any additional costs.
Question 19: Explain the function of Amazon Route 53.
Answer: Amazon Route 53 is the DNS (Domain Name System) web service from AWS. This Amazon web service offers high availability and reliability. Amazon Route 53 provides a reliable and cost-effective way for developers to route users to Internet applications. It does that by translating a domain name to an IP address, and Amazon Route 53 complies with IPv6 too.
Amazon Route 53 connects user requests to the IT infrastructure running in AWS. E.g., it can connect to Amazon EC2 instances, “Elastic Load Balancing” load balancers, and Amazon S3 buckets.
Question 20: What is an AWS edge location?
Answer: An AWS edge location is an endpoint in AWS that’s used for caching content. Edge locations are not AWS regions, and they are located in many major cities. The purpose of an edge location is to deliver content to end-users with reduced latency. Edge locations in AWS consist of CloudFront and the CDN (Content Delivery Network) from AWS.
Question 21: What is Amazon EMR?
Answer: Amazon EMR (Elastic MapReduce) is a managed cluster platform from AWS to run big data frameworks like Apache Hadoop and Apache Spark. This helps organizations to analyze very large data sets. You can use Apache Hive and Apache Pig too on Amazon AMR. Amazon EMR helps you to process data for analytics and business intelligence.
Amazon EMR has a cluster as its central component. Such a cluster is a collection of EC2 instances, and these multiple instances are called “nodes”. Nodes have specific roles. There are 3 types of nodes on Amazon EMR, namely, “Master node”, “Core node”, and “Task node”.
Interview questions and answers for hiring mid-level AWS developers
Use the following interview questions for hiring mid-level AWS developers:
Question 22: Can you use Amazon S3 with EC2 instances? If yes, explain how to do this.
Answer: Note that Amazon S3 is for object-based storage. On the other hand, Amazon EBS is for block storage, and Amazon EFS is for file storage. You can’t mount S3 on EC2.
However, you can access S3 objects from EC2 instances. This is applicable for instances with root devices backed by the local instance storage.
AWS offers several tools to load AMIs into Amazon S3. You can also move them from Amazon S3 to Amazon EC2 instances.
Question 23: Explain the differences between Amazon RDS and Amazon DynamoDB.
Answer: Amazon RDS is the relational database management service offered by AWS. This deals with SQL databases. This offering automates many key services like backup, patching, and upgrading. As you would expect, you can store structured data only in Amazon RDS. You will need to follow the rows-and-columns structure that’s required in an RDBMS.
Amazon DynamoDB is a NoSQL database service. By their very design, NoSQL databases differ widely from SQL databases. E.g., NoSQL databases don’t follow the table-column-row structure. Furthermore, you can store unstructured data in a NoSQL database. All of these differences apply to the Amazon RDS vs Amazon DynamoDB comparison.
Question 24: What is a “Snowball” in AWS?
Answer: A “Snowball” in AWS is an option to transport data inside and outside of AWS environment. It’s a petabyte-scale data transport solution. Snowball uses secure appliances to transfer a massive amount of data into and out of the AWS cloud. With Snowball, you can resolve common challenges with large-scale data transfers, e.g.:
- High network costs;
- Long transfer times;
- Security concerns.
Question 25: What is Amazon SQS (Simple Queue Service)?
Answer: Amazon SQS is a fully-managed message queuing service. This helps you to decouple and scale microservices, distributed systems, and Serverless applications. You can use Amazon SQS to send, store, and receive messages between software components. The maximum size of a message in SQS is 256 KB.
Question 26: Explain the use of the CloudWatch metrics.
Answer: Amazon CloudWatch offers useful metrics to track the performance of your application systems. Several AWS services provide free metrics for resources like Amazon EC2 instances, Amazon EBS volumes, Amazon RDS DB instances, etc.
Amazon CloudWatch enables you to implement detailed monitoring for resources like Amazon EC2 instances. You can use CloudWatch to publish the metrics for your own application. CloudWatch can load all the metrics in your account, which enables search. You can see charts with these metrics. Furthermore, you can set up alarms using CloudWatch.
Question 27: Which AWS product helps you to stream data in real time?
Answer: Amazon Kinesis Firehose is the AWS product that helps you to reliably load streaming data into data lakes, data stores, and analytics services in real time. You can use Amazon Kinesis Firehose to deliver streaming data to Amazon S3, Amazon Redshift, and Amazon Elasticsearch Service.
Amazon Kinesis Firehose can deliver streaming data to generic HTTP endpoints. You can use it to deliver streaming data to Datalog, New Relic, MongoDB, and Splunk too.
Amazon Kinesis Firehose is a fully-managed service. It scales to match the throughput of data, and you don’t need to administer it on an ongoing basis.
Question 28: What is Amazon Redshift?
Answer: Amazon Redshift is a data warehouse service from AWS. It has the following characteristics:
- It’s a fully-managed service.
- Redshift offers speed and powerful features. It uses ML (Machine Learning), parallel query execution, and columnar storage on high-performance disk to offer high performance.
- Redshift allows you to run petabytes of data in a Redshift data warehouse. It supports exabytes of data in a data lake built on Amazon S3.
- Redshift supports structured and semi-structured data.
Question 29: Why would one use Amazon Glacier?
Answer: Amazon Glacier is a low-cost cloud storage service offered by AWS. It’s suitable for data that can have a longer retrieval time than other data.
If you have data that is not accessed frequently, then you can move it to a cold data cloud service. This kind of archival storage service saves costs. E.g., you can move database backups to such archival storage. Amazon Glacier is good for such purposes.
Question 30: Where can you use an Amazon NAT (Network Address Translation) gateway?
Answer: You can use an Amazon NAT gateway when you use a VPC (Virtual Private Cloud) on AWS. A VPC is a private cloud, however, it’s stored in a public cloud. The cloud provider secures and isolates it. AWS provides VPC services.
You can use a NAT gateway to enable instances in a private subnet to connect to the Internet or other AWS services. At the same time, an unauthorized Internet user can’t initiate a connection with these instances. You need to pay if you create and use an Amazon NAT gateway.
Question 31: How to differentiate between the elasticity and scalability of a software system?
Answer: A system might be able to handle the increased workload by adding hardware resources. It should give back the additional resources allocated to it when the workload reduces. The combination of these capabilities is called “elasticity” in the context of a software system.
The scalability of a software system refers to its capability to increase the hardware resources for meeting higher demands. The system can achieve this by increasing the hardware specifications. Alternatively, the system can achieve this by increasing the number of processing nodes.
AWS interview questions to hire senior developers
Hiring senior AWS developers? Use the following interview questions:
Question 32: Explain how AWS Elastic Beanstalk applies updates.
Answer: AWS Elastic Beanstalk, the popular PaaS (Platform-as-a-Service) platform from AWS mitigates risks in the update process arising from failures. It creates a duplicate copy of an instance before updating it. AWS Elastic Beanstalk routes traffic to the duplicate instance after that.
It then starts the update process in the original instance. In the case of a failure in the update process, AWS Elastic Beanstalk restores the original instance. It uses the backup instance for this.
Question 33: Mention use cases where you can use the “Classic Load Balancer” and the “Application Load Balancer”.
Answer: You can use the “Classic Load Balancer” when you need simple load balancing of traffic across different EC2 instances. Using an “Application Load Balancer” is a better option if you use container-based or microservices architecture patterns. These patterns often involve routing traffic to different services. These patterns might involve load balancing across multiple ports on one EC2 instance, and the “Application Load Balancer” works better.
Question 34: Can you modify the security group rules that are being used by multiple EC2 instances?
Answer: You can modify security groups that are being used by multiple EC2 instances. AWS implements the changes to the security group rules immediately. You don’t need to restart the instances. Furthermore, AWS applies these rules to the EC2 instances running previously.
Question 35: What purpose do the lifecycle hooks perform at the time of auto-scaling?
Answer: When an auto-scaling group launches instances or terminates them, the lifecycle hooks perform custom actions. They pause the instances for this.
An instance moves to a “wait” state when it’s paused. The default duration for an instance to remain in this state is 1 hour. You can install the software of your choice after pausing an instance. Alternatively, you can check the readiness of the instance to receive traffic. These are the advantages of pausing an instance.
Question 36: Explain the process of securing access to your S3 bucket.
Answer: You can secure access to your S3 bucket using the following options:
- ACL (Access Control List): You can use an ACL to manage access to buckets and objects. An object of each bucket will have an association with the ACL. It contains information about which AWS accounts have access to the bucket. This information also includes the type of access. Amazon S3 creates an ACL by default when you create a bucket. AWS checks ACLs to verify whether a user has access to particular resources.
- Bucket policies: You can apply bucket policies only to S3 buckets. These policies define the actions that are allowed or denied. The policies defined for a bucket apply to all the objects in an S3 bucket.
Question 37: How many types of AMI does AWS offer, and what are they?
Answer: AWS offers two types of AMIs (Amazon Machine Images), which are as follows:
- Instance store-backed: An instance store-backed AMI is an EC2 instance. The root device of this instance resides on the hard drive of the virtual machine. If you create a new instance, AWS copies the AMI. You can’t stop instances that you have created using this kind of AMI. You need to keep such instances running until you complete your work with them.
- EBS-backed: An EBS-backed instance is an EC2 instance. It uses an EBS (Elastic Block Store) volume as a root device. EBS volumes are restricted to availability zones. You can stop EBS-backed instances. Even if you stop such an instance, you can use the EBS volume later. An AMI includes a block device mapping device that determines the volumes to attach to the instance when it is launched.
Question 38: What is a key pair in Amazon EC2?
Answer: EC2 uses public-key cryptography to encrypt and decrypt the login information of users. In public-key cryptography, there are two keys. A public key encrypts the information. The recipient of the information uses a private key to decrypt the encrypted data. The combination of the public and private keys is called a key pair.
Question 39: Name the different instance types in AWS.
Answer: AWS has the following instance types:
- “General purpose instances”: Businesses use these for most of the use cases.
- Compute-optimized instance”: Organizations use them for applications that require high CPU usage.
- “GPU instances”: These are suitable for gaming applications.
- “Memory-optimized instances”: Organizations use them for memory-intensive apps.
- “Storage optimized instances”: These are suitable for high-frequency online transaction processing systems, RDBMSs, NoSQL databases, and data warehousing applications.
Question 40: What is Amazon WorkMail?
Answer: Amazon WorkMail is a secure offering for business email and calendar services. It supports desktop and mobile. Users can manage their inbound and outbound emails, contacts, and calendars. They can use popular email clients like Microsoft Outlook. WorkMail uses SMTP (Simple Mail Transfer Protocol) to send emails, which is the most common email protocol.
These AWS interview questions and answers will help you hire competent AWS developers. If you need further help, please contact us at DevTeam.Space.
AWS offers many cloud computing services, e.g., compute, storage, databases, networking, etc. However, that doesn’t make your project an easy one. The project requirements determine the complexity. We recommend a judicious mix of junior, intermediate, and senior developers.
While many developers have AWS skills, not everyone has the experience of delivering complex projects. Finding experienced AWS developers can take time. Plan your hiring process accordingly.
Migration to any cloud platform requires detailed planning, and AWS isn’t an exception. You need to consider factors like security when planning such a migration. You should hire an experienced AWS architect for such projects.