AWS Interview Questions for Beginners and Freshers
1. What is AWS?
Amazon Web Services or AWS is a robust and widely preferred cloud platform that offers a variety of cloud-based services such as:
- Networking
- Storage
- Computing
Powered by Amazon, AWS empowers organisations and developers to deploy, scale, and manage their applications without physical infrastructure.
2. What are the key services provided by AWS?
AWS offers numerous services that are categorised into different domains. Some of the key services include:
- Compute: Amazon EC2, AWS Lambda
- Storage: Amazon S3, Amazon EBS
- Databases: Amazon RDS, Amazon DynamoDB
- Networking: Amazon VPC, Amazon Route 53
- Analytics: Amazon EMR, Amazon Redshift
Auto-scaling enables the automatic provisioning and launch of new instances, allowing you to automatically increase or decrease resource capacity in response to demand.
4. What is geo-targeting in CloudFront?
Geo-targeting is the practice of delivering personalised content to users based on their geographical location without altering the URL. This enables businesses to create tailored content that resonates with specific local audiences and addresses their unique needs.
5. How many types of deployment models exist in the cloud?
There are three primary deployment models in the cloud. They are:
- A private cloud is utilised by a single organisation and inaccessible to the public. It is ideal for organisations that manage sensitive applications.
- Public cloud, whose resources are managed by third-party service providers like Amazon Web Services and Microsoft Azure.
- A hybrid cloud combines private and public clouds, allowing some servers to remain on-site while extending other capabilities to the cloud. This approach offers flexibility and cost-effectiveness.
6. What are the five characteristics of cloud computing?
Cloud computing is defined by five key characteristics such as:
- On-demand self-service
- Broad network access
- Multi-tenancy and resource pooling
- Rapid elasticity and scalability
- Measured service
7. What is the relationship between the Availability Zone and the AWS region?
AWS regions are separate geographical areas. Each region contains multiple isolated locations, known as Availability Zones, which are linked by low-latency connections.
8. Is there any alternative tool to log into the cloud environment besides the console?
The following tools can help you log into the AWS resources:
- Putty
- AWS CLI for Linux
- AWS CLI for Windows
- AWS CLI for Windows CMD
- AWS SDK
- Eclipse
9. Explain S3 in AWS.
Amazon S3, or Simple Storage Service, is a scalable storage service that allows users to store and retrieve any amount of data from any web location at any time. It is designed for 99.999999999% durability or 11 nines.
10. What is the difference between S3 and EBS?
S3 or Simple Storage Service stores and retrieves any amount of data. It is highly durable and accessible over the Internet. EBS (Elastic Block Store) is a block storage service used as storage volumes for EC2 instances. It provides persistent storage that can be attached to EC2 instances.
11. Is it possible to vertically scale on an Amazon Instance? If yes, how?
Following are the steps to scale an Amazon Instance vertically:
- Spin up a more prominent Amazon instance than the existing one.
- Pause the existing instance to remove the root ebs volume from the server and discard.
- Stop the live running instance and detach its root volume.
- Note the unique device ID and attach that root volume to the new server.
- Start the instance again.
12.What is the number of buckets that can be created in AWS by default?
Each of the AWS accounts can hold one hundred buckets. If additional buckets are required, you can submit a service limit increase to increase the bucket limit.
13. Explain VPC.
A Virtual Private Cloud (VPC) enables you to create a logically isolated portion of the AWS cloud where you can deploy AWS resources within a virtual network that you configure. You have full control over your virtual networking environment.
14. What distinguishes public subnets from private subnets??
A Public Subnet is linked to a route table with a route to an internet gateway. Thus, the subnet’s resources can communicate with the Internet.
A Private Subnet lacks a route to an internet gateway, so its resources cannot connect directly to the Internet.
15. Explain IAM.
IAM, or Identity and Access Management, is an AWS service that allows you to securely manage access to AWS services and resources. You can create and manage AWS users and groups and establish permissions to allow or deny their access.
Basic AWS Interview Questions
1. What is EC2?
Amazon Web Services (AWS) offers Amazon Elastic Compute Cloud (EC2), a web service that delivers scalable computing power in the cloud.It allows users to run virtual servers, known as instances, on-demand.
2. What is SnowBall?
AWS SnowBall is a service that enables the physical transfer of large amounts of data into and out of the AWS cloud using secure, rugged storage devices. It helps with data migration and eliminates the need for a high-speed internet connection.
AWS provides Amazon CloudWatch, a service focused on monitoring and observability. It gathers and manages metrics, monitors log files, establishes alarms, and responds automatically to modifications in AWS resources. CloudWatch helps in gaining insights into the performance and operational health of AWS resources.
4. What is an Elastic Transcoder?
Amazon Elastic Transcoder is a scalable and fully managed media transcoding service. It allows users to convert media files from their source format into versions that will play back on devices like smartphones, tablets, and PCs.
5. What do you understand about VPC?
A Virtual Private Cloud (VPC) is a logically isolated section of the AWS Cloud where users can launch AWS resources in a defined virtual network. It allows users to have control over their network environment, including selection of IP address range, creation of subnets, and configuration of route tables and network gateways.
6. Under which category of Cloud Service do DNS and Load Balancer Services fall?
DNS (Domain Name System) and Load Balancer Services fall under the category of Networking Services in the cloud.
7. Which Storage Classes are offered in Amazon S3?
Amazon Simple Storage Service (S3) offers various storage classes, including Standard, Intelligent-Tiering, Standard-IA (Infrequent Access), One Zone-IA, Glacier, and Glacier Deep Archive.
8. Explain what T2 instances are?
T2 instances are a type of Amazon EC2 instance that belongs to the Burstable Performance Instances family. They provide a baseline level of CPU performance with the ability to burst above the baseline when needed, making them suitable for workloads with variable compute requirements.
9. What are Key-Pairs in AWS?
In AWS, key pairs serve the purpose of ensuring secure access to EC2 instances. They consist of a public key that is stored on the instance and a private key that the user possesses. To securely and authenticate the connection to the EC2 instance, use the private key.
10. How many Subnets can you have per VPC?
In AWS, you can have a maximum of 200 subnets per VPC.
11. List different types of Cloud Services.
Cloud services can be categorised into Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS). Examples include EC2 (IaaS), AWS Elastic Beanstalk (PaaS), and Amazon S3 (SaaS).
Advanced AWS Interview Questions
1. Explain what S3 is?
Amazon S3, known as Simple Storage Service, is a scalable service for object storage offered by AWS. It allows users to store and retrieve data from anywhere on the web and is designed to provide 99.999999999% (11 nines) durability. S3 is commonly used for data backup, archiving, content distribution, and serving as a foundation for various AWS services.
2. How does Amazon Route 53 ensure both high availability and low latency in its services?
Amazon Route 53 achieves high availability and low latency through a global network of DNS servers. It uses anycast routing, enabling the DNS requests to be automatically routed to the nearest available DNS server. This minimises latency and enhances the overall performance of the service. Additionally, Route 53 supports health checks and automatic failover, directing traffic away from unhealthy or unavailable resources, and contributing to the service's reliability.
3. What is the process for initiating a request to Amazon S3?
To initiate a request to Amazon S3, users typically send an HTTP request to the S3 service endpoint. The request includes the necessary information such as the HTTP method (GET, PUT, POST, DELETE), the bucket name, the object key, and other optional parameters. Amazon S3 supports a RESTful API, allowing users to interact with the service programmatically. Additionally, AWS SDKs and command-line tools simplify the process of working with S3.
4. What does AMI include?
An Amazon Machine Image (AMI) includes a pre-configured virtual machine image, which includes an operating system, application server, and applications. It also includes launch permissions that control which AWS accounts can use the AMI to launch instances. AMIs serve as templates for creating Amazon EC2 instances, providing a consistent environment for applications.
5. What are the different types of Instances?
Amazon EC2 instances come in various types, including General Purpose (e.g., t3, m5), Compute Optimised (e.g., c5), Memory Optimised (e.g., r5), Storage Optimised (e.g., i3), and Accelerated Computing (e.g., p3). Each instance type is designed to cater to specific use cases, such as compute-intensive, memory-intensive, storage-intensive, or GPU-accelerated workloads.
6. Explain the correlation between an Availability Zone and a Region in the context of AWS.
In AWS, a Region is a geographical area consisting of multiple Availability Zones (AZs). Availability Zones are isolated locations within a Region, each with its own power, cooling, and networking. The correlation ensures high availability and fault tolerance. Resources deployed across multiple Availability Zones in a Region are designed to withstand failures in one zone, providing resilience and continuity of service.
7. How do you monitor Amazon VPC?
Amazon VPC (Virtual Private Cloud) can be monitored using AWS CloudWatch, which provides metrics and logs for VPC-related resources. Key metrics include data transfer, packet rates, and resource utilisation. Additionally, VPC Flow Logs capture information about IP traffic going to and from network interfaces in the VPC, aiding in traffic analysis and troubleshooting.
8. Enumerate the various types of EC2 instances categorised based on their associated costs.
EC2 instances can be categorised into On-Demand Instances (pay-as-you-go), Reserved Instances (reserved capacity for a fixed term with significant cost savings), and Spot Instances (bid for unused capacity, cost-effective but can be terminated with short notice). Each category offers flexibility in cost management based on different usage patterns.
9. Define the concepts of stopping and terminating an EC2 Instance and their implications.
Stopping an EC2 instance halts its execution, but the associated resources (such as storage and network interfaces) remain intact. It can be restarted later. Terminating an instance, however, permanently deletes the instance and its associated resources. Stopping is suitable for temporary pauses, while termination is a permanent action.
10. Outline the consistency models available for modern databases provided by AWS.
AWS provides two consistency models: eventual consistency and strong consistency. Eventual consistency allows for temporary inconsistencies but guarantees that, over time, all replicas will converge to a consistent state. Strong consistency ensures immediate and synchronised updates across all replicas, providing a consistent view of the data at all times.
11. What is Geo-Targeting in CloudFront?
Geo-targeting in Amazon CloudFront allows content delivery based on the geographical location of the viewer. By configuring CloudFront with Geo-Targeting, content providers can serve customised content or redirect users based on their geographic location, enhancing the user experience and optimising content delivery.
12. What are the advantages of AWS IAM?
AWS Identity and Access Management (IAM) provides centralised control over AWS account security. Advantages include the ability to manage user access, create and manage groups, define policies, enable multi-factor authentication, and integrate with AWS services for fine-grained access control. IAM enhances security by enforcing the principle of least privilege.
13. What do you understand about a Security Group?
In AWS, a Security Group acts as a virtual firewall for instances in a VPC. It controls inbound and outbound traffic by specifying rules that allow or deny traffic based on protocols, ports, and source or destination IP addresses. Security Groups are associated with instances and operate at the instance level, providing a layer of security for EC2 instances.
14. What are Spot Instances and On-Demand Instances?
Spot Instances in AWS are spare computing capacity instances available at a lower cost. Users bid for this capacity and can lose access on short notice if the capacity is needed elsewhere. On-demand instances, on the other hand, are instances available for immediate use at standard rates with no upfront commitment, providing flexibility and scalability.
15. Explain Connection Draining?
Connection Draining is a feature in AWS Elastic Load Balancing (ELB) that allows the load balancer to complete in-flight requests made to instances being taken out of service. It ensures a smooth transition during scale-in or maintenance activities, preventing disruption to the end-user experience.
16. Differentiate between a Stateful Firewall and a Stateless Firewall?
A Stateful Firewall monitors the status of ongoing connections and makes decisions by considering the context of the traffic. It understands the state of the connection and can enforce rules accordingly. In contrast, a Stateless Firewall filters traffic based solely on source and destination information, without considering the state of the connection.
17. What is Power User Access in AWS?
Power User Access is an AWS Identity and Access Management (IAM) user type with permissions to perform common actions required for daily tasks but without the ability to manage IAM users and groups, create policies, or access sensitive resources. It provides a balance between administrative control and restriction for users.
18. Define the characteristics of an Instance Store Volume and an EBS Volume?
An Instance Store Volume is ephemeral storage directly attached to an EC2 instance, offering high I/O performance but data is lost if the instance is stopped or terminated. An EBS (Elastic Block Store) Volume is persistent storage that can be attached to EC2 instances and persists independently of the instance's lifecycle. EBS volumes are suitable for critical data and can be detached and reattached to different instances.
19. What are the Recovery Time Objective and Recovery Point Objective in AWS?
Recovery Time Objective (RTO) is the targeted duration within which a system should be restored after a disruption to meet business continuity requirements. Recovery Point Objective (RPO) is the acceptable amount of data loss, representing the point in time to which systems and data must be recovered after an outage. Both metrics are crucial for designing resilient and effective disaster recovery strategies in AWS.
20. Can a file larger than 100 Megabytes be uploaded to Amazon S3?
Yes, Amazon S3 supports the multipart upload feature, which allows users to upload large files in parts. This feature enables parallelization of uploads, better resilience to network issues, and the ability to resume uploads from where they left off. Once all parts are uploaded, they can be combined into a single object.
21. Is it possible to alter the Private IP Address of an EC2 instance while it is operational or in a halted state?
No, it is not possible to alter the private IP address of an EC2 instance while it is operational. The private IP address is assigned during the instance launch and remains associated with the instance until termination. If an alteration is required, the instance needs to be stopped, the private IP address changed in the configuration, and then the instance restarted.
22. What is the use of lifecycle hooks in Autoscaling?
Lifecycle hooks in AWS Autoscaling allow users to perform custom actions before instances are launched or terminated. These hooks provide a way to control the instance's state during the scaling process, allowing for additional setup or validation. For example, an instance can be paused for further configuration before being fully in service.
23. What are the configurable policies for managing user passwords within AWS?
AWS IAM provides password policies that can be configured to enforce security standards. These policies include settings for password length, complexity, expiration, and the ability to prevent password reuse. By configuring these policies, AWS users can enhance the overall security of their accounts and comply with organisational password requirements.
AWS Interview Questions for Intermediate
1. What is CloudWatch?
The Amazon CloudWatch has the following features:
- Depending on multiple metrics, it participates in triggering alarms.
- It helps monitor AWS environments like CPU utilisation, EC2, Amazon RDS instances, Amazon SQS, S3, Load Balancer, SNS, etc.
2. Name some of the AWS services that are not region-specific.
AWS services that are not region-specific are:
- IAM
- Route 53
- Web Application Firewall
- CloudFront
3. How many total VPCs per account/region and subnets per VPC can you have?
You can have a maximum of 5 VPCs per account and region and 200 subnets for each VPC. If you require additional VPCs or subnets, you can ask AWS support for a quota increase. For instance, you could raise your VPC limit to 1000 per region and request a higher subnet limit.
4. What is an Elastic Transcoder?
We need to adjust the video's resolution and format to accommodate various devices with different resolutions, such as laptops, tablets, and smartphones. This can be efficiently archived using an AWS service called the Elastic Transcoder. This cloud-based media transcoding tool provides exactly what is needed—a user-friendly, cost-effective, and highly scalable solution for businesses and developers.
5. What is Amazon Virtual Private Cloud, and what are its uses?
Amazon Virtual Private Cloud (VPC) enables you to create a virtual AWS network that resembles a traditional network in an on-premises data centre. VPC isolates resources, controls inbound and outbound traffic, and segments workloads into subnets with strict security configurations. It provides granular control over IP ranges, security groups, and network access control lists.
6. Describe the steps involved in a CloudFormation solution.
- Create or use an existing CloudFormation template in JSON or YAML.
- Save the template in an S3 bucket.
- Use AWS CloudFormation to call the bucket and create a stack on your template.
- CloudFormation reads and provisions the services defined in the template in the specified order.
7. What is the name of Amazon's Content Delivery Network?
Amazon CloudFront is a CDN service that is used in AWS. It helps deliver static content to the end-user through the nearest available server, hence reducing latency.
8. How will you configure an Amazon S3 bucket to serve static assets for your public web application?
When creating a bucket to serve static assets to your public web application, you must uncheck the “disable all public access” option.
Snowball is an application designed to transfer terabytes of data into and out of the AWS cloud. It uses secured physical storage to transfer the data. Snowball is a petabyte-scale data transport solution that helps with cost and time savings.
10. Define Snapshots in Amazon Lightsail.
Snapshots are point-in-time backups of EC2 instances, block storage drives, and databases. They can be produced manually or automatically at any moment. Even after they are created, snapshots can always be used to restore your resources. These resources will also perform the same tasks as the original ones from which the snapshots were made.
11. How can you effectively manage and secure secrets in CI/CD pipelines using AWS?
To securely handle CI/CD pipelines, you can use AWS Secrets Manager or AWS Systems Manager Parameter Store to sensitive data, such as:
- API keys
- Database passwords
- Certificates
Both services seamlessly integrate with AWS offerings like CodePiepline and CodeBuild, enabling safe access to secrets without embedding them in your codebase. With this IAM-enables access control, you can ensure that only authorised entities can access sensitive data within the CI/CD process.
12. How does AWS Solution Architect function?
The
AWS solutions architect’s function is to:
- Design and oversee applications on AWS
- Ensure scalability and optimal performance
- Guide developers, system administrators, and customers to leverage AWS for business requirements and communicate intricate concepts to technical and non-technical audiences.
13. What are DOS and DDoS attacks, and what are the measures to mitigate them?
A Dos or Denial of Service attack is a malicious attempt to disrupt user access to a specific system, such as a website or an application. A DDoS or Distributed Denial of Service (DDoS) attack is a malicious attempt to launch an attack using multiple sources. They are categorised based on the layer of the Open Systems Interconnection (OSI) model they target. The most prevalent DDoS attacks affect the following layers:
- Network
- Application
- Transportation
- Presentation
14. What purpose does AWS CloudFormation serve?
AWS CloudFormation allows you to define and provision your AWS resources using a template file. It allows you to represent your infrastructure as code, facilitating AWS resource deployment and management automation.
Amazon Machine Image or AMI is a pre-set template for an EC2 instance that includes all the details required to launch the instance, such as the operating system, installed applications, and application server.
AWS Interview Questions for Experienced Candidates
1.What is the difference between stopping and terminating an EC2 instance?
While you may think that stopping and terminating are the same, there is a difference. When you stop an EC2 instance, it performs a normal shutdown and moves to a stopped state. However, when you terminate the instance, it is transferred to a stopped state, and the EBS volumes attached to it are deleted and can never be recovered.
2. What are Solaris and AIX operating systems? Are they available with AWS?
Solaris is an operating system that uses SPARC processor architecture, which is currently not supported by the public cloud. AIX runs only on Power CPU, not Intel, meaning you cannot create AIX instances in EC2. Both operating systems have limitations, so they are unavailable with AWS.
3. What are the common types of AMI designs?
There are many types of AMIs, but some of the common AMIs are:
- Fully Baked AMI
- Just Enough Baked AMI (JeOS AMI)
- Hybrid AMI
4. How do you allow a user to gain access to a specific bucket?
You need to follow the four steps provided below to allow access. They are:
- Categorise your instances
- Define how authorised users can manage specific servers.
- Lockdown your tags
- Attach your policies to IAM users
5. VPC is not resolving the server through DNS. What might be the issue, and how can you fix it?
To fix this problem, you need to enable the DNS hostname resolution to resolve the situation.
6. How do you connect multiple sites to a VPC?
You can use the AWS VPN CloudHub to provide secure communication between sites if you have multiple VPN connections. Here’s a diagram showing how to connect various sites to a VPC.
7. What is the maximum number of S3 buckets you can create?
The maximum number of S3 buckets that can be created is 100. However, if you need more buckets, you can request AWS support to increase the S3 bucket quota and increase the limit to 1000 buckets per account.
8. How can you save the data on root volume on an EBS-backed machine?
Two scenarios can happen with an EBS-backed machine:
- Shutting down the machine: Data persists when you shut down an EBS-backed machine.
- Terminating the machine: When an EC2 instance is terminated, the EBS is automatically deleted. To save the data, you can take a snapshot of the example before terminating the EC2 machine.
9. What does an AMI include?
AMI stands for Amazon Machine Images. It includes the following:
- You can create single or multiple Amazon Elastic Block Store (Amazon EBS) snapshots and templates for the instance's root volume.
- Launch permissions that let AWS accounts use AMI to launch instances.
- A block device mapping specifies what volumes will be attached to the instance during its launch.
10. If you launch a standby RDS, will it be launched in the same availability zone as your primary?
No, standby instances are automatically launched in different availability zones than the primary, making them physically independent infrastructures. This is because the whole purpose of standby instances is to prevent infrastructure failure. So, if the primary goes down, the standby instance will help recover the data.
11. Which Amazon solution will you use to accelerate moving petabytes of data in and out of AWS using storage devices designed to be secure for data transfer?
AWS Snowball is the data transport solution for large amounts of data that need to be moved into and out of AWS using physical storage devices. It can be helpful when moving petabyte-scale data because transporting it physically via snowball devices is much cheaper than transferring it over the Internet and is a faster tool.
12. What are the services used to create a centralised logging solution in AWS?
- Amazon CloudWatch Logs: Monitors and stores log files.
- Amazon S3: Centralized log storage.
- Amazon ElasticSearch service: To search, analyse, and visualise logs.
- Amazon Kinesis Firehose: Transports log data from S3 to Amazon ElasticSearch.
13. Describe the native AWS Security logging capabilities.
- AWS CloudTrail: Provides a history of AWS API calls for every account, which is helpful for security analysis, resource change tracking, and auditing.
- AWS Config offers detailed information about configuring AWS resources and records configuration changes, which can be sent as notifications.
14. How do you set up a system in AWS to monitor website metrics in real-time?
Amazon CloudWatch monitors various metrics, such as state changes in EC2, auto-scaling lifecycle events, scheduled events, and API calls. You can set up custom dashboards and alarms to get real-time insights.
15. Explain what T2 instances are.
T2 Instances are low-cost general-purpose instance types that allow the CPU to burst to a higher performance whenever the workload demands it and provide a moderate baseline performance. They are usually used where workloads do not consistently or often use the CPU.
AWS Interview Questions and Answer - Scenario Based
1. You have a microservices application that needs to scale dynamically based on traffic. How would you design an architecture for this using AWS services?
I would use:
- Amazon ECS or EKS for container orchestration
- AWS Auto Scaling to modify the number of instances based on CPU or custom metrics
- Application Load Balancers for traffic distribution
- Amazon CloudWatch to monitor and trigger scaling events
2. Your application's database is experiencing performance issues. What AWS tools will you use to resolve this problem?
To resolve performance issues, I would use:
- Amazon RDS Performance Insights to identify bottlenecks
- CloudWatch Metrics to monitor performance
- AWS X-Ray to trace requests
I'd also consider optimising queries and using read replicas if necessary.
3. You are launching an instance from AMI under the free usage tier with a 50 GB snapshot size. How will you launch the instance under this tier?
It is not possible to launch this instance under the free usage tier.
4. A content management system running on an EC2 instance is approaching 100% CPU utilisation. How can you lessen the load on the EC2 instance?
You can achieve this by attaching a load balancer to an auto-scaling group, which effectively distributes the load across multiple instances.
5. If your team currently uses Jenkins CI/CD, how will you transition to a serverless CI/CD model and reduce your management efforts?
I would use AWS CodePipeline with CodeBuild because they integrate seamlessly, enabling the creation of serverless CI/CD pipelines without the need for infrastructure management.
6. How will you achieve Single Sign-On (SSO) for multiple AWS accounts while maintaining security?
I recommend using AWS Single Sign-On (SSO) to manage user access across multiple AWS accounts. By setting up SSO integrations, users can securely access multiple accounts without requiring individual credentials.
7. Your company is aiming for high availability by deploying applications across multiple regions. How could you implement global traffic distribution?
I would utilise Amazon Route 53 with Latency-Based or Geolocation Routing to guide traffic to the nearest or most suitable region based on the user's location.
8. How will you enable HTTPS for security if your application's front end is hosted on S3?
I would utilise Amazon CloudFront to deliver content from the S3 bucket, set up a custom domain, and link an SSL/TLS certificate via AWS Certificate Manager.
9. Your company is aiming for high availability by deploying applications across multiple regions. How could you implement global traffic distribution?
I would use Amazon Route 53 with geolocation or latency-based routing to direct traffic to the closest or most appropriate region based on user location.
10. Your application generates a significant number of logs. How could you centralise log management and enable efficient analysis?
I would use the following tools:
- Amazon CloudWatch Logs to centralise log storage
- AWS CloudWatch Logs Insights to query and analyse logs
These tools will simplify troubleshooting and monitor application behaviour.
11. How will you design a cost-effective solution for an application that stores and retrieves large volumes of unstructured data?
Based on data access behaviours, I would choose Amazon S3 with suitable storage classes, such as S3 Standard or S3 Intelligent Tiering. This approach ensures a durable and cost-efficient way to store unstructured data.
12. Your team wants to enable automated testing for infrastructure deployments. How could you achieve this?
I would integrate AWS CloudFormation StackSets into the CI/CD pipeline. StackSets allow you to deploy infrastructure templates to multiple accounts and regions, enabling automated testing of infrastructure changes.
13. Your application uses AWS Lambda functions, and you want to improve cold start performance. How could you address this challenge?
I would implement an Amazon API Gateway with the HTTP proxy integration, creating a warm-up endpoint that periodically invokes Lambda functions to keep them warm.
14. Your organisation is concerned about data protection and compliance. How will you ensure the secure storage and transmission of sensitive data?
I will use Amazon S3 server-side encryption and Amazon RDS encryption at rest for data storage. I would also use SSL/TLS encryption for communication between services and implement security best practices for data transmission.
AWS Interview Questions - Multiple-Choice
1. What is the primary purpose of AWS EFS (Elastic File System)?
- A. Block storage for EC2 instances
- B. Object storage for large-scale data
- C. Shared file storage for multiple instances
- D. Archival storage for infrequent access
Answer: C. Shared file storage for multiple instances
2. Which AWS service is used for managing large-scale batch processing workloads?
- A. AWS Batch
- B. AWS Step Functions
- C. AWS Glue
- D. Amazon EMR
Answer: A. AWS Batch
3. In AWS CloudFront, what is the primary role of an Edge Location?
- A. To store data backups
- B. To cache content closer to users
- C. To process Lambda functions
- D. To manage load balancing
Answer: B. To cache content closer to users
4. Which AWS database service is designed to provide ultra-low latency and in-memory caching?
- A. Amazon RDS
- B. Amazon ElastiCache
- C. Amazon DynamoDB
- D. Amazon Neptune
Answer: B. Amazon ElastiCache
5. What is the function of AWS Artifact?
- A. Manage compliance-related documents and reports
- B. Provide storage for application logs
- C. Create IAM policies automatically
- D. Monitor AWS resources for threats
Answer: A. Manage compliance-related documents and reports
6. Which feature of AWS Lambda allows you to connect it with AWS services or custom applications?
- A. Lambda Layers
- B. Event Source Mapping
- C. Execution Context
- D. Auto Scaling
Answer: B. Event Source Mapping
7. What is the primary purpose of an AWS Elastic IP address?
- A. To provide an IP address that persists even if an instance is stopped
- B. To scale compute resources
- C. To host multiple applications on a single EC2 instance
- D. To connect to a private subnet
Answer: A. To provide an IP address that persists even if an instance is stopped.
8. What does a "Target Group" represent in an AWS Load Balancer?
- A. A set of rules for routing traffic
- B. A group of EC2 instances or containers that receive traffic
- C. A DNS name for the load balancer
- D. A scaling configuration for Auto Scaling
Answer: B. A group of EC2 instances or containers that receive traffic
9. What AWS service is used explicitly for securing APIs?
- A. AWS WAF
- B. Amazon API Gateway
- C. AWS Shield
- D. AWS Cognito
Answer: B. Amazon API Gateway
10. Which service provides centralised access management across multiple AWS accounts?
- A. AWS IAM
- B. AWS Organizations
- C. AWS Trusted Advisor
- D. AWS SSO
Answer: B. AWS Organizations
11. What is a key feature of Amazon Macie?
- A. Securely transfer files between S3 buckets
- B. Automate key rotation for encryption
- C. Discover and protect sensitive data in S3 buckets
- D. Manage API Gateway endpoints
Answer: C. Discover and protect sensitive data in S3 buckets
12. What is the maximum retention period for CloudWatch logs?
- A. 1 year
- B. 10 years
- C. Indefinite until explicitly deleted
- D. 5 years
Answer: C. Indefinite until explicitly deleted
13. Which AWS service enables you to transfer petabyte-scale data into the cloud using physical devices?
- A. AWS Direct Connect
- B. AWS Snowball
- C. Amazon S3 Transfer Acceleration
- D. AWS DataSync
Answer: B. AWS Snowball
14. What is the primary use of AWS CloudHSM?
- A. To manage distributed denial-of-service (DDoS) attacks
- B. To provide hardware-based key storage for cryptographic operations
- C. To generate IAM policies
- D. To encrypt S3 bucket data automatically
Answer: B. To provide hardware-based key storage for cryptographic operations
15. what does the "Cross-Zone Load Balancing" feature do in AWS Elastic Load Balancer?
- A. Redirects traffic to healthy instances only
- B. Distributes incoming traffic evenly across all instances in all availability zones
- C. Caches requests for frequently accessed content
- D. Automatically adjusts the number of instances in an Auto Scaling group
Answer: B. Distributes incoming traffic evenly across all instances in all availability zones.
AWS Cloud Computing Interview Questions and Answers
1. Explain the AWS Shared Responsibility Model.
This model defines the security responsibilities of AWS (security of the cloud) and customers (security in the cloud). AWS also manages infrastructure security, while customers handle data protection, application security, and identity management.
2. What AWS service will you use to run containerised applications without managing servers?
I would use AWS Fargate to run containers without managing servers or clusters.
3. How is Amazon S3 Standard different from Amazon S3 Glacier?
Amazon S3 is often used to access data with low latency and high throughput. S3 Glacier is used for archival storage, and retrieval times range from minutes to hours.
4. Explain the AWS Elastic Beanstalk environment.
The Elastic Beanstalk environment is an application deployment platform with scalable architecture, compute resources like EC2 and ELB, database instances, and a scalable architecture.
5. What is the role of Amazon Route S3?
It is a robust and scalable Domain Name System (DNS) service that directs traffic to both AWS resources and external sites, featuring health checks and latency-based routing capabilities.
6. What are placement groups in Amazon EC2?
Placement groups are a way to control the placement of instances. Types include:
- Cluster: Instances in a single AZ for low-latency communication.
- Spread: Instances spread across hardware for fault tolerance.
- Partition: Instances split into partitions, reducing the impact of hardware failure.
7. How do Amazon CloudWatch and AWS CloudTrail differ?
CloudTrail logs API calls and activities in your account for auditing. CloudWatch monitors metrics, events, and logs for resources and applications.
8. What is Amazon Cognito used for?
Amazon Cognito is used for identity management. It allows developers to add user sign-in and sign-up and enables access control to web and mobile apps.
9. How does AWS Storage Gateway work?
AWS Storage Gateway facilitates hybrid cloud storage by linking on-premise software to cloud storage for:
- Disaster recovery
- Backup
- Archiving
10. Explain Elastic Network Interface (ENI).
ENI is a virtual network interface attached to an EC2 instance to provide multiple IP addresses, network traffic separation, or failover for networking.
11. What roles do AWS Identity and Access management serve?
IAM roles grant temporary access to AWS resources without sharing long-term credentials. They are assigned to users, applications, or services that require specific permissions.
12. What is the use of AWS CloudFront signed URLs and signed cookies?
These features restrict access to private content distributed via CloudFront. Signed cookies grant access to multiple files, while signed URLs provide temporary access to specific files.
13. What are the benefits of AWS Elastic Load Balancer (ELB) as opposed to a single EC2 instance?
ELB distributes incoming traffic across multiple instances to improve fault tolerance, scalability, and availability compared to using a single EC2 instance.
14. What is the difference between Amazon RDS and Amazon DynamoDB?
Amazon RDS is a relational database service that supports SQL databases like MySQL, PostgreSQL, and Oracle. Amazon DynamoDB is a NoSQL database designed for key-value and document-based workloads with high performance and scalability.
AWS Interview Questions and Answers on Amazon EC2
AWS EC2 is a service Amazon offers to help customers host compute services in their IT environment as part of cloud computing. It removes all of the manual setups typically involved in running virtual servers. It gives you complete control over your computing resources, which you can scale as needed.
2. What are the different pricing models for Amazon EC2?
- On-Demand Instances: Pay-as-you-go pricing, no long-term commitment
- Reserved Instances: Significant discounts for 1- or 3-year commitments
- Spot Instances: Cost-effective, but instances can be interrupted
- Savings Plans: Flexible pricing for consistent workloads
- Dedicated Hosts: Physical servers for compliance and licensing needs.
3. What is an EC2 Instance Type? Give an example.
EC2 instance types define the hardware of the host computer. Examples:
- t2.micro:
General-purpose instance
- c5.large: Compute-optimized instance
4. What is the difference between Amazon EC2 and AWS Lambda?
- Amazon EC2: Virtual servers for running applications; you manage the OS and scaling.
- AWS Lambda: Serverless, event-driven compute service where AWS manages scaling and infrastructure.
5. What is the role of EC2 key pairs?
Key pairs (public and private keys) are used to securely connect to an EC2 instance via SSH. The public key is stored in AWS, while the user keeps the private key.
6. Explain EC2 User Data and its use.
EC2 User Data is a script or set of commands provided during instance launch. It automates instance initialisation tasks, such as installing software or configuring the instance.
7. What are Reserved Instances in AWS EC2?
Amazon Web Services (AWS) provides EC2 Reserved Instances for customers to use for various tailor-made purposes. Amazon charges an hourly rate for these instances and offers an optional capacity reservation option.
8. Explain the benefits of AWS EC2.
- Reliability: Each Amazon EC2 region in the Amazon Web Services network has an SLA of 99.9% availability. Thus, instance replacement is simple and fast.
- Security: Amazon implements Amazon VPC to deliver stable networking and security. The compute instances reside in a virtual private cloud (VPC) logically partitioned with a specific IP range.
- Flexibility: Choosing an EC2 instance can involve different factors such as types, software packages, instance storage, and operating systems. You can configure the memory, CPU, and boot partition size to suit the operating system and application.
- Cost Saving: EC2 is cost-effective because it enables consumers to configure plans to suit their needs, saving them money and maximising their resources. Amazon has significant savings because the power and scale of its EC2 instance are significantly lower in cost compared to other cloud providers.
9. Explain the Best Practices For Amazon Ec2.
To receive the most benefits and satisfaction from and in Amazon EC2:
- Security and Network Best Practices
- Storage
- Resource Management
- Backup and Recovery
10. Why is EC2 Important?
- No need for any hardware.
- Scalable up and down.
- Pay for what you use.
- Full control of the machine.
- Secure
- Accessible from anywhere in the world via internet-enabled devices.
AWS Solution Architect: Interview Questions and Answers
1. What are the core principles of AWS Well-Architected Framework?
- Operational Excellence
- Security
- Reliability
- Performance Efficiency
- Cost Optimization
- Sustainability (added recently)
2. How do you choose the right AWS Region for your application?
Consider the following factors:
- Latency for end-users
- Compliance with legal or regulatory requirements
- Service availability in the region
- Cost differences between regions
3. How are horizontal and vertical scaling different?
- Horizontal scaling is the addition of more instances, such as EC2, behind an ELB for load distribution.
- Vertical scaling increases the resources of a single instance, such as CPU and RAM, and upgrades an EC2 instance type.
4. How do you ensure high availability in AWS?
- Use multiple Availability Zones within a Region
- Set up load balancers ALB and ELB
- Enable auto-scaling groups.
- Implement failover mechanisms (e.g., Route 53 health checks).
5. What is Amazon Route 53, and how is it used?
Amazon Route 53 is a scalable Domain Name System service used for:
- Domain Registration
- DNS routing
- Traffic management with health checks
- Implementing latency-based routing or geo-location-based routing.
6. What are AWS SQS, SNS and SES?
- Amazon Simple Queue Service is a reliable, scalable, and fully managed message queuing service that operates quickly.
- Amazon Simple Notification Service (SNS) allows you to send messages individually or broadcast them to multiple recipients quickly and efficiently while remaining fully managed.
- Amazon Simple Email Service (SES) is a cost-effective and scalable email solution that empowers developers to send emails from their applications.
7. What is the role of Elastic Beanstalk?
Elastic Beanstalk makes it easy to deploy and scale web applications and services developed using Java, .NET, PHP, Node.js, Python, Ruby, Go, and Docker. It operates on shared servers like Apache, Nginx, Passenger, and IIS.
AWS OpsWorks is a cloud orchestration tool that allows developers and system administrators to oversee server deployments and applications using the DevOps methodology. It streamlines operational tasks, including software updates, scaling instances, and monitoring. OpsWorks also supports a flexible architecture that enables configuration management using Chef and Puppet.
9. How would you secure data in transit and at rest in AWS?
- Data in Transit: Use SSL/TLS for encryption during transmission.
- Data at Rest: Use services like AWS KMS (Key Management Service) or S3 bucket encryption. Enable encryption for EBS volumes.
10. What storage classes are available in Amazon S3, and in what scenarios would you utilise each?
- S3 Standard: Frequently accessed data.
- S3 Intelligent-Tiering: For unpredictable access patterns.
- S3 Standard-IA: Infrequently accessed data with lower retrieval cost.
- S3 Glacier: Archival storage.
- S3 One Zone-IA: For data that doesn’t require multi-AZ resilience.
11. How do you design a multi-tier architecture on AWS?
- Frontend Layer: Amazon CloudFront and ELB for traffic distribution.
- Application Layer: EC2 or AWS Lambda for compute services.
- Database Layer: RDS, DynamoDB, or Aurora for data storage.
- Monitoring: Use CloudWatch for performance tracking.
AWS IAAS Interview Questions and Answers
1. What is AWS IaaS? How does it differ from PaaS and SaaS?
IaaS, or Infrastructure as a Service, provides virtualised computing resources like EC2, EBS, and S3. The user manages the OS, applications, and runtime.
PaaS, or Platform as a Service, enables the development and deployment of applications like Elastic Beanstalk.
SaaS or Software as a Service helps manage software applications like Amazon WorkSpaces.
2. What core IaaS services does AWS provide?
- Compute: Amazon EC2
- Storage: Amazon S3, EBS
- Networking: Amazon VPC, Elastic IPs
- Database: Amazon RDS
3. How does Amazon EC2 differ from AWS Lambda in the context of IaaS?
- Amazon EC2: Virtual servers where users control OS, configuration, and scaling.
- AWS Lambda: Serverless computing where users only manage the code, and AWS handles scaling and infrastructure.
4. How do EBS and Instance Store differ in AWS EC2?
EBS, or Elastic Block Store, is persistent and durable. It can be attached or detached from instances. Instance Store is temporary storage tied to the lifecycle of the EC2 instance.
5. How does AWS Elastic Load Balancer enhance IaaS scalability?
ELB distributes incoming application traffic across multiple EC2 instances, ensuring high availability and scalability.
6. What is the role of Auto Scaling in AWS IaaS?
Auto-scaling adjusts the number of EC2 instances based on demand, ensuring cost efficiency and optimal performance.
7. How can you configure high availability for applications hosted on EC2?
Distribute instances across multiple Availability Zones (AZs):
- Use ELB to balance traffic
- Use ELB for traffic distribution.
- Set up Auto Scaling for fault tolerance.
- Use RDS Multi-AZ deployments for database redundancy.
8. How important are Elastic Network Interfaces in AWS IaaS?
Elastic Network Interfaces serve as a logical networking component within a VPC, allowing multiple network interfaces to be attached to EC2 instances. They facilitate failover, high availability, and improved network management.
9. What is an AWS Elastic IP, and how is it applied in IaaS?
An Elastic IP is a static IPv4 address tailored for dynamic cloud computing. It enables the association of a fixed IP address with an EC2 instance, ensuring consistent connectivity even after a restart.
10. How does AWS CloudFormation assist in IaaS management?
AWS CloudFormation allows to define infrastructure as a code (IaC) and automates the provisioning and management of resources like EC2, VPCs, and ELBs.
AWS VPC Interview Questions and Answer
1. What is AWS VPC, and how does it facilitate network isolation and customisation for cloud resources?
AWS VPC is a dedicated, logically isolated segment of the AWS Cloud where you can deploy AWS resources. It supports network isolation and customisation by enabling you to set up your network parameters, such as IP address ranges, route tables, and subnets. This enhances control and security over your cloud assets.
2. What is the primary distinction between public and private subnets in an AWS VPC?
A public subnet in a VPC connects to a route table that routes traffic to the Internet via an Internet Gateway (IGW), making it accessible from the Internet. On the contrary, a private subnet does not connect to an IGW and is designed for resources that are not meant to be directly accessed from the internet.
3. What purpose do Network Access Control Lists (NACLs) in AWS VPC serve? How different are they from security groups?
NACLs manage traffic permissions at the subnet level according to a defined set of rules. Unlike Security Groups, NACLs are stateless and evaluate traffic on a per-rule basis, making them less granular but providing broader traffic control.
4. What is an AWS VPC Peering connection, and when is it used in a multi-VPC architecture?
VPC Peering connects two VPCs, allowing instances in both VPCs to communicate seamlessly with each other. This connection is particularly useful for establishing a shared network or facilitating resource sharing between different VPCs, such as in a multi-tier application that separates development and production environments.
5. What is the purpose of AWS Transit Gateway in a VPC architecture, and what are its advantages?
The AWS Transit Gateway is a fully managed service that streamlines connectivity among VPCs and on-premise networks. It simplifies centralised routing management and enhances connectivity in complex, multi-VPC environments, reducing the administrative challenges associated with managing multiple connections.
6. Explain AWS Site-to-Site VPN and how it secures communication between on-premise networks and VPCs.
The AWS Site-to-Site VPN is a service that secures on-premise networks to Amazon Web Services. To ensure communication between an on-premise network and a VPC or Virtual Private Cloud, the AWS Site-to-Site VPN employs encrypted tunnels to maintain data confidentiality and integrity.
7. Describe the function of VPC Endpoints in AWS and how they can improve security and performance for VPC resources.
VPC Endpoints enable your VPC to connect directly to AWS Services like S3 and DynamoDB without going through the public internet. This enhances security by limiting exposure to the internet and boosts performance by minimising latency, which is particularly beneficial for data-heavy applications.
8.How does a Network Address Translation (NAT) Gateway function within a VPC? How does it allow instances in a private subnet to reach the internet?
A NAT Gateway permits instances in private subnets to send outbound traffic to the internet and blocks incoming connections. It functions as a network address translator for private instances, ensuring they have internet access.
9. Explain a VPC Flow Log and how it is used in a VPC.
A VPC Flow Log records details about IP traffic entering and leaving the network interfaces in a VOC. They can be used for various purposes in a VPC, such as:
- Monitoring
- Troubleshooting
- Security assessments
- Gathering insights about traffic behaviour
- Identifying and resolving network issues
10. What is the function of a Route Table in AWS VPC, and how do they determine the network traffic flow?
Route Tables in a VPC determine the path of network traffic by defining routes to various destinations, such as subnets and the internet. Each subnet is associated with a specific route table, allowing you to control traffic flow within the VPC and external networks.
AWS Lambda Interview Questions and Answer
AWS Lambda is a serverless compute service that runs code in response to events and automatically manages the underlying compute resources for you.
2. How does AWS Lambda handle scaling?
AWS Lambda automatically scales by running code in response to each trigger. Your code runs in parallel and processes each trigger individually, scaling with the size of the workload.
3. What are some common applications for AWS Lambda?
AWS Lambda is used for:
- Real-time file processing
- Data transformation
- Event-driven applications
- Back-end services for web and mobile applications
4. How to monitor and troubleshoot AWS Lambda functions?
AWS CloudWatch allows you to track and log your Lambda functions. CloudWatch Logs, CloudWatch Metrics and AWS X-Ray help you track performance and troubleshoot issues.
5. List the challenges of AWS Lambda.
AWS Lambda imposes a maximum execution time of 15 minutes, a maximum zipped package size of 50 MB, and allows for a maximum memory allocation of 3,008 MB.
6. How do you secure AWS Lambda functions?
Utilise AWS Identity and Access Management (IAM) roles to manage access, encrypt environment variables, and secure the network with VPCscurity.
7. Can you explain the concept of cold starts in AWS Lambda?
A cold start occurs when a Lambda function is invoked after not being used for a while. This causes a slight delay as the function container is initialised, affecting performance. However, keeping functions warm mitigates this.
8. How do you optimise the performance of AWS Lambda functions?
Optimise performance by minimising package size, reusing connections, using appropriate memory allocation, and keeping functions warm.
9. What are the key features of AWS Lambda?
AWS Lambda packs a punch with several standout features:
- Scalability: It automatically adjusts to match your workload, allowing your functions to easily manage high and low traffic.
- Pay-per-use pricing means you pay only for the compute time required for your functions, which is well-suited for applications with variable workloads.
- Integration with AWS Services: It easily integrates with other AWS services, enabling you to create complex applications by combining them with tools like Amazon S3, Kinesis, or Dynamo.
- Multi-linguistic Support: It supports various programming languages, such as Python, Node.js, C#, Java, Ruby, and Go.
- Easy deployment and management: AWS Lambda provides an intuitive interface for deploying and managing functions. You can easily monitor and troubleshoot your functions through the AWS Management Console or the AWS CLI.
10. How can you monitor the performance of AWS Lambda functions?
Keeping an eye on your Lambda functions ensures they run smoothly and don’t break the bank. AWS gives you a few tools to help:
- AWS CloudWatch: Tracks metrics like invocation count, errors, duration, and concurrency. It also logs detailed info about invocation requests and responses.
- AWS X-Ray: Helps you debug and analyse your functions with request tracing and mapping to find performance bottlenecks.
- AWS Lambda Insights: An enhanced monitoring solution integrated into CloudWatch, offering a deeper look into performance metrics and issues.
AWS Interview Questions and Answers for Elastic Load Balancing
1. Explain AWS Elastic Load Balancing (ELB) and its importance.
ELB distributes incoming application traffic across multiple targets like:
- EC2 instances
- IP addresses
- Containers
These targets are distributed across one or more Availability Zones to ensure high availability, application scalability, and fault tolerance.
2. What are the types of AWS ELBs available?
- Application Load Balancer (ALB), which is ideal for HTTP/HTTPS traffic with advanced routing based on request content.
- Network Load Balancer (NLB), which provides ultra-low latency and is best for TCP / UDP protocols.
- Gateway Load Balancer (GWLB) is designed to deploy, scale, and manage virtual appliances.
- Classic Load Balancer (CLB) is a legacy load balancer that supports HTTP/HTTPS and TCP protocols.
3. How does ELB support fault tolerance?
ELB routes traffic to healthy targets in multiple Availability Zones. If a target becomes unhealthy, it stops routing traffic until it recovers, ensuring application reliability.
4. What is a Target Group in Elastic Load Balancing?
A Target Group is a collection of targets (e.g., EC2 instances or IP addresses) to which ELB routes traffic. Each load balancer can have multiple target groups, allowing traffic to be directed based on routing rules.
5. How does AWS ELB handle health checks?
ELB periodically performs health checks on registered targets using a defined protocol and path. It stops routing traffic to targets that fail the health check until they become healthy.
6. Can Elastic Load Balancers handle HTTPS traffic? If so, how?
An ELB can manage HTTPS traffic by utilising SSL/TLS certificates. You can either upload SSL certificates through AWS Certificate Manager (ACM) or manually upload your own certificates to ensure secure communication.
7. What is the difference between a listener and a rule in ELB?
Listener: A process that checks for connection requests on a specific port and protocol.
Rule: A condition that defines how traffic is routed based on request parameters (e.g., host headers, path). Rules are associated with listeners.
8. How can Elastic Load Balancers scale to handle spikes in traffic?
ELB automatically scales to handle varying traffic loads by dynamically adjusting its capacity. It ensures sufficient resources to manage traffic spikes and maintains consistent performance.
9. What security features does ELB offer?
- Integration with Security Groups and Network ACLs to manage inbound and outbound traffic.
- Support for SSL Termination for encrypting data in transit.
- Access Logs for monitoring and analysing traffic patterns.
- Integration with AWS WAF to protect against common web exploits.
10. Explain cross-zone load balance and how it works.
Cross-zone load balance in AWS evenly distributes incoming traffic across all registered targets in the enabled Availability Zones, regardless of the target’s zone. This feature enhances resource utilisation and ensures uniform traffic distribution.
AWS Route 53 Interview Questions and Answers
1. What is AWS Route 53 and its primary purpose?
AWS Route 53 is a scalable and easily available Domain Name System (DNS) web service that links user requests to resources running in AWS or externally. It also offers domain registration, DNS routing, and health-checking capabilities.
2. What routing policies does Route 53 support?
Route 53 supports the following routing policies:
- Simple Routing: Default maps a domain to a single resource.
- Weighted Routing: Distributes traffic based on assigned weights.
- Latency Routing: Directs traffic to the region with the lowest latency.
- Geolocation Routing: Routes traffic based on geographic location.
- Failover routing: Redirects traffic to a backup resource when the primary is unhealthy.
- Multi-Value Answer Routing: Returns multiple IP addresses with health checks.
3. How does Route 53 ensure high availability?
Since Route 53 uses globally distributed DNS servers, it ensures high availability by:
- Ensuring low latency and redundancy
- Supporting failover routing and health checks
- Rerouting traffic to healthy endpoints during outages
4. What are hosted zones in Route 53?
A hosted zone is a container for records associated with a domain. It represents the DNS settings for a domain and its subdomains. There are two types of hosted zones:
Public Hosted Zone: For domains accessible over the internet.
Private Hosted Zone: For domains accessible only within a VPC.
5. What are Route 53 health checks, and how do they work?
Health checks track the health of resources such as applications and web servers by sending periodic requests and verifying their responses. Route 53 also stops routing traffic to resources that do not respond during health checks.
6. How does Route 53 integrate with other AWS services?
Route 53 integrates seamlessly with:
- CloudFront: For content delivery.
- Elastic Load Balancer (ELB): To route traffic to healthy endpoints.
- S3: For hosting static websites.
- VPC: For private DNS zones.
7. How do Alias and CNAME records vary in Route 53?
Alias Record maps domain names to AWS resources like CloudFront, ELB, or S3. It is free and integrates with AWS-specific services.
CNAME Record, on the other hand, maps a domain name to another, but it cannot be used for root domains.
8. What is DNS failover in Route 53, and how is it implemented?
DNS failover redirects traffic to a backup resource when the primary resource becomes unhealthy. It uses health checks and routing policies, such as failover or multi-value answer routing.
9. How does Route 53 handle domain registration?
Route 53 allows users to:
- Register automatically
- Renew domain names
- Manage DNS records for registered domains
- Transfer domain registrations from other registrars.
10. What is a Time-to-Live or TTL in Route 53, and why is it important?
TTL specifies how long a DNS resolver caches a response from Route 53 before making another request. Lower TTL values allow quicker updates to DNS records, while higher TTL values reduce DNS query load.
AWS EKS Interview Questions and Answers
1. What is AWS EKS, and what is its primary purpose?
Amazon Elastic Kubernetes Service is a managed Kubernetes service that simplifies containerised applications' deployment, management, and scaling using Kubernetes on AWS infrastructure. It eliminates the need to install, operate, and maintain Kubernetes control planes.
2. What are the key components of Amazon EKS?
Key components of Amazon EKS include:
- Control Plane: Managed by AWS to handle Kubernetes API requests and ensure high availability.
- Worker Nodes: EC2 instances or Fargate tasks running your containerised applications.
- Kubelet: Agent running on each worker node to communicate with the control plane.
3. What is the difference between EKS and ECS?
- EKS: Based on Kubernetes, it supports multi-cloud and hybrid architectures.
- ECS: AWS-native container orchestration, tightly integrated with AWS services but limited to the AWS ecosystem.
4. What is the use of the EKSCTL tool?
The EKS CTL tool creates and manages EKS clusters. It simplifies provisioning and enables users to create clusters with a single command.
5. How does EKS support high availability?
- EKS control plane runs across three Availability Zones.
- Kubernetes workloads can be distributed across multiple worker nodes and Availability Zones for fault tolerance.
6. What is IAM’s role in EKS?
IAM is used for authentication and authorisation in EKS and manages access to the Kubernetes API server. Roles can be assigned to worker nodes, pods, or users to control resource access.
7. What are managed node groups in EKS?
Managed node groups allow AWS to automate the provisioning and lifecycle management of EC2 instances (worker nodes) for your EKS cluster, including updates, scaling, and instance health monitoring.
8. How can you monitor an EKS cluster?
EKS integrates with tools like:
- Amazon CloudWatch: For logs and metrics.
- AWS X-Ray: For tracing distributed applications.
- Prometheus and Grafana: For detailed monitoring and visualisation.
9. What is the use of Fargate with EKS?
AWS Fargate allows Kubernetes pods to run without managing the underlying infrastructure. It removes the need to provision and manage EC2 instances for worker nodes.
10. How do you secure an EKS cluster?
Key security practices include:
- Restricting access using IAM roles and Kubernetes RBAC (Role-Based Access Control).
- Enabling VPC Private Endpoints to isolate the cluster.
- Using Secrets Manager or Kubernetes Secrets to store sensitive data.
- Applying Pod Security Policies to enforce security configurations.
