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Thursday, October 24, 2024

AWS DevOps Interview Questions and Answers

 


100 AWS DevOps Interview Questions and Answers

General AWS DevOps Questions

  1. What is DevOps?

    DevOps is a set of practices that integrates software development (Dev) and IT operations (Ops) to shorten the development lifecycle and deliver features, fixes, and updates frequently in close alignment with business objectives.

  2. What are the benefits of using AWS for DevOps?

    AWS provides flexible services like Elastic Compute Cloud (EC2), Elastic Container Service (ECS), and Elastic Beanstalk, which help automate and scale development and deployment pipelines. Features include scalability, automation, CI/CD, Infrastructure as Code (IaC), and monitoring tools.

  3. What is Infrastructure as Code (IaC) in AWS?

    IaC refers to managing and provisioning infrastructure through code instead of manual processes. In AWS, you can implement IaC using AWS CloudFormation and AWS CDK (Cloud Development Kit).

  4. Explain the difference between DevOps and Agile.

    Agile is a methodology that focuses on iterative development, whereas DevOps is a practice that bridges the gap between development and operations to ensure faster and more reliable software delivery.

  5. What are some popular AWS DevOps tools?

    • AWS CodePipeline (CI/CD)
    • AWS CodeBuild (build automation)
    • AWS CodeDeploy (deployment automation)
    • AWS CloudFormation (IaC)
    • Amazon ECS/EKS (container orchestration)

CI/CD Pipeline Questions

  1. What is a CI/CD pipeline?

    A CI/CD pipeline automates the steps in software development, from integration, testing, deployment, to delivery, ensuring continuous improvement and delivery of applications.

  2. How would you implement a CI/CD pipeline in AWS?

    You can use AWS CodePipeline to create a CI/CD pipeline. Combine CodeCommit (source control), CodeBuild (build), and CodeDeploy (deployment) for a complete pipeline.

  3. Explain AWS CodePipeline.

    AWS CodePipeline is a continuous integration and continuous delivery service that helps automate build, test, and deploy phases of your release process every time there is a code change.

  4. What is AWS CodeBuild?

    AWS CodeBuild is a fully managed build service that compiles your source code, runs tests, and produces artifacts that are ready for deployment.

  5. What is AWS CodeDeploy?

    AWS CodeDeploy automates code deployments to any instance, including Amazon EC2 instances and on-premises servers.

Containerization and Orchestration

  1. What are containers?

    Containers are lightweight, standalone executable packages that include everything needed to run an application, including code, runtime, libraries, and system dependencies.

  2. What is the difference between Docker and a Virtual Machine (VM)?

    Docker containers virtualize at the OS level, while VMs virtualize at the hardware level. Containers are more lightweight, sharing the host OS kernel, whereas each VM runs a full guest OS.

  3. How do you orchestrate containers in AWS?

    Use Amazon ECS (Elastic Container Service) or Amazon EKS (Elastic Kubernetes Service) to manage and orchestrate containerized applications.

  4. What is Amazon ECS?

    Amazon ECS is a fully managed container orchestration service that allows you to run, stop, and manage containers in a cluster.

  5. What is Amazon EKS?

    Amazon EKS is a managed service that makes it easy to run Kubernetes on AWS without needing to install and operate your own Kubernetes control plane.

AWS Elastic Beanstalk and Lambda

  1. What is AWS Elastic Beanstalk?

    AWS Elastic Beanstalk is a platform-as-a-service (PaaS) that allows you to deploy and manage applications in various languages like Java, Python, Ruby, etc., without worrying about infrastructure.

  2. How do you deploy an application using Elastic Beanstalk?

    You can deploy an application using Elastic Beanstalk through its management console, CLI, or CI/CD pipeline. Upload your application and specify the environment configuration.

  3. What is AWS Lambda?

    AWS Lambda is a serverless compute service that runs your code in response to events and automatically manages the compute resources for you.

  4. How does AWS Lambda integrate with CI/CD?

    You can deploy AWS Lambda functions as part of a CI/CD pipeline using AWS CodePipeline, CodeBuild, and CodeDeploy. Lambda functions can also be triggered by changes in repositories like CodeCommit or GitHub.

  5. What are the limitations of AWS Lambda?

    AWS Lambda has limits such as a maximum of 15 minutes execution time, 10 GB of memory, and limited support for certain libraries and dependencies.

AWS EC2 and Load Balancing

  1. What is Amazon EC2?

    Amazon Elastic Compute Cloud (EC2) is a web service that provides resizable compute capacity in the cloud.

  2. What is an EC2 instance?

    An EC2 instance is a virtual server in AWS that can be used to run applications on the AWS cloud.

  3. How can you automatically scale EC2 instances?

    Use Auto Scaling Groups and AWS CloudWatch to monitor your instances and automatically scale the number of instances based on predefined conditions, such as CPU utilization.

  4. What is Elastic Load Balancer (ELB)?

    ELB is a service that automatically distributes incoming traffic across multiple EC2 instances, containers, or IP addresses to ensure high availability.

  5. What are the types of load balancers in AWS?

    • Application Load Balancer (ALB)
    • Network Load Balancer (NLB)
    • Gateway Load Balancer (GLB)

AWS CloudFormation and Automation

  1. What is AWS CloudFormation?

    AWS CloudFormation is a service that allows you to model, provision, and manage AWS infrastructure as code by using templates.

  2. How does CloudFormation help with DevOps?

    It enables automated provisioning and management of infrastructure, reducing the manual effort and errors while ensuring consistent environments across development, staging, and production.

  3. What is a CloudFormation stack?

    A CloudFormation stack is a collection of AWS resources that you can manage as a single unit using CloudFormation.

  4. How do you update a CloudFormation stack?

    Update the CloudFormation stack by modifying the template and applying the changes. AWS will automatically determine the changes required and apply them.

  5. Can you roll back CloudFormation changes?

    Yes, CloudFormation supports rollback on failure, where if any resource creation or update fails, it will automatically roll back all changes to the last known good state.

AWS Monitoring and Logging

  1. What is AWS CloudWatch?

    AWS CloudWatch is a monitoring and management service that provides data and actionable insights for AWS resources, applications, and services.

  2. What are CloudWatch Alarms?

    CloudWatch Alarms watch a metric over time and perform an action based on predefined thresholds, such as sending notifications or scaling EC2 instances.

  3. How does AWS CloudTrail help in monitoring?

    AWS CloudTrail logs API calls made in your account, providing visibility into user activity and changes to resources, which helps in auditing and compliance.

  4. What is AWS X-Ray?

    AWS X-Ray helps developers analyze and debug distributed applications, such as those built using a microservices architecture, by tracing requests and monitoring their performance.

  5. How do you integrate CloudWatch with a CI/CD pipeline?

    Use CloudWatch metrics and alarms to trigger actions like automated deployments or rollbacks in a CI/CD pipeline.

AWS IAM and Security

  1. What is AWS IAM?

    AWS Identity and Access Management (IAM) is a service that allows you to manage access to AWS services and resources securely.

  2. What are IAM roles?

    IAM roles are used to delegate access to users or services, allowing them to interact with AWS services without needing long-term credentials.

  3. What is an IAM policy?

    An IAM policy is a JSON document that defines permissions and controls what actions are allowed or denied for AWS resources.

  4. How can you secure your CI/CD pipeline in AWS?

    Use IAM roles and policies to ensure that only authorized users and services can access your CI/CD pipeline. Implement encryption for sensitive data and use logging to monitor access.

  5. What is AWS KMS?

    AWS Key Management Service (KMS) is a managed service that allows you to create and manage encryption keys and control the use of encryption across AWS services.

AWS Security and Best Practices

  1. What is AWS Shield?

    AWS Shield is a managed Distributed Denial of Service (DDoS) protection service that safeguards applications running on AWS. AWS Shield comes in two tiers: Standard and Advanced.

  2. What is AWS WAF?

    AWS Web Application Firewall (WAF) helps protect your web applications from common web exploits like SQL injection and cross-site scripting (XSS) by allowing you to define rules that allow or block specific requests.

  3. How do you secure data in transit and at rest in AWS?

    For data in transit, use SSL/TLS encryption. For data at rest, AWS provides services like S3 server-side encryption (SSE), AWS KMS, and EBS encryption.

  4. How can you implement MFA in AWS?

    AWS provides Multi-Factor Authentication (MFA) to add an extra layer of security by requiring two forms of identification to access AWS services. It can be enabled via IAM for user accounts.

  5. What is AWS Secrets Manager?

    AWS Secrets Manager helps you securely store and manage access to credentials, API keys, and other secrets necessary for accessing AWS services or third-party applications.

Version Control and AWS CodeCommit

  1. What is AWS CodeCommit?

    AWS CodeCommit is a fully managed source control service that allows you to privately store and manage Git repositories in the cloud.

  2. How does AWS CodeCommit integrate with CI/CD pipelines?

    AWS CodeCommit integrates seamlessly with AWS CodePipeline, triggering builds and deployments when changes are committed to the repository.

  3. What is the difference between CodeCommit and GitHub?

    Both are Git-based version control systems. CodeCommit is fully managed by AWS with tighter integration into AWS services, while GitHub is an external Git hosting service with broader community features.

  4. How do you automate code deployment from CodeCommit to EC2 instances?

    You can automate code deployment using CodePipeline, CodeDeploy, and CodeCommit, where CodePipeline triggers a deployment when a commit is pushed, and CodeDeploy deploys the code to EC2 instances.

  5. Can you integrate CodeCommit with external CI/CD tools like Jenkins?

    Yes, CodeCommit can be integrated with Jenkins using AWS SDKs and APIs. Jenkins can poll the repository and trigger builds based on changes.

AWS Auto Scaling

  1. What is AWS Auto Scaling?

    AWS Auto Scaling automatically adjusts the capacity of your resources to maintain performance and availability at the lowest possible cost.

  2. How does Auto Scaling work with EC2?

    You create Auto Scaling groups, define scaling policies (such as scaling based on CPU usage), and AWS will automatically increase or decrease the number of EC2 instances as needed.

  3. What is the difference between vertical and horizontal scaling?

    • Vertical scaling refers to increasing the size (e.g., CPU, memory) of an instance.
    • Horizontal scaling refers to adding more instances to handle increased traffic.

  4. What is a launch configuration in Auto Scaling?

    A launch configuration is a template that an Auto Scaling group uses to launch EC2 instances, specifying the instance type, AMI, key pair, and security groups.

  5. How do you set up a highly available system using Auto Scaling and ELB?

    Create an Auto Scaling group spread across multiple Availability Zones (AZs), associate it with an Elastic Load Balancer (ELB), and configure health checks to ensure traffic is only routed to healthy instances.

AWS S3 and Storage

  1. What is Amazon S3?

    Amazon Simple Storage Service (S3) is an object storage service that provides scalability, security, and performance for storing any amount of data from anywhere.

  2. What are the different storage classes in S3?

    • S3 Standard
    • S3 Intelligent-Tiering
    • S3 Standard-IA (Infrequent Access)
    • S3 One Zone-IA
    • S3 Glacier
    • S3 Glacier Deep Archive

  3. What is versioning in S3?

    S3 versioning allows you to keep multiple versions of an object in the same bucket, protecting against accidental deletions or overwrites.

  4. How does S3 encryption work?

    S3 supports server-side encryption (SSE) with S3-Managed Keys (SSE-S3), AWS KMS-Managed Keys (SSE-KMS), and customer-provided keys (SSE-C). It also supports client-side encryption where the encryption is handled outside of S3.

  5. How do you manage permissions for S3 buckets?

    Permissions for S3 buckets can be managed using bucket policies, ACLs (Access Control Lists), and IAM policies.

AWS Networking

  1. What is a VPC in AWS?

    Amazon Virtual Private Cloud (VPC) allows you to create a private, isolated section of the AWS cloud where you can launch AWS resources in a virtual network that you define.

  2. What is a subnet in VPC?

    A subnet is a range of IP addresses in your VPC. You can launch AWS resources into a subnet. Subnets can be public (access to the internet) or private (no internet access).

  3. What is an Internet Gateway (IGW)?

    An IGW is a horizontally scaled, redundant, and highly available VPC component that allows communication between instances in your VPC and the internet.

  4. What is a NAT Gateway?

    A NAT Gateway allows instances in a private subnet to access the internet while preventing inbound traffic from the internet.

  5. What are security groups and NACLs in AWS?

    • Security Groups act as a virtual firewall at the instance level, controlling inbound and outbound traffic.
    • Network Access Control Lists (NACLs) provide stateless traffic filtering at the subnet level.

  6. What is VPC Peering?

    VPC Peering is a networking connection between two VPCs that allows you to route traffic between them privately using IPv4 or IPv6 addresses.

  7. What is AWS Direct Connect?

    AWS Direct Connect is a dedicated network connection from your premises to AWS, allowing for faster and more secure data transfer.

  8. How do you achieve high availability in a VPC?

    Use multiple Availability Zones (AZs) within a region, set up load balancers, and design failover mechanisms for critical resources.

  9. What is Amazon Route 53?

    Amazon Route 53 is a scalable DNS and domain name registration service that routes end-user requests to AWS services or other internet resources.

  10. How do you implement a multi-region architecture in AWS?

    Use AWS services like Route 53 for DNS failover, replicate data across regions using services like S3 Cross-Region Replication, and leverage multi-region databases like Amazon DynamoDB Global Tables.

AWS Elastic Container Service (ECS)

  1. What is Amazon ECS?

    Amazon Elastic Container Service (ECS) is a fully managed container orchestration service that helps you run and scale containerized applications on AWS.

  2. What is the difference between ECS and EKS?

    ECS is a native AWS service for container orchestration, while EKS is a fully managed Kubernetes service that provides a Kubernetes control plane in AWS.

  3. What is an ECS Task?

    An ECS task is a running instance of a task definition, which includes the Docker container configuration, networking, and other settings for your containers.

  4. What is a Fargate launch type in ECS?

    AWS Fargate is a serverless compute engine for containers that allows you to run containers without having to manage the underlying infrastructure.

  5. How does ECS integrate with IAM?

    ECS allows you to assign IAM roles to tasks, enabling your containers to access AWS resources securely.

AWS Elastic Kubernetes Service (EKS)

  1. What is Amazon EKS?

    Amazon Elastic Kubernetes Service (EKS) is a fully managed service that allows you to run Kubernetes on AWS without managing the Kubernetes control plane.

  2. What is the difference between EKS and Kubernetes?

    EKS is a managed service that handles the Kubernetes control plane for you, while Kubernetes requires you to manually set up and manage the control plane. EKS also provides integration with AWS services like IAM and VPC.

  3. How do you deploy a Kubernetes application to EKS?

    You can deploy Kubernetes applications to EKS using kubectl. First, set up your EKS cluster, configure kubectl to use it, and then apply your Kubernetes manifests or Helm charts.

  4. How does EKS integrate with IAM?

    EKS integrates with IAM to control access to the Kubernetes control plane. IAM roles can also be mapped to Kubernetes service accounts to manage permissions for your workloads.

  5. What is eksctl?

    eksctl is a command-line tool that simplifies the creation, management, and deletion of Amazon EKS clusters. It abstracts away the complexity of setting up EKS clusters by providing a simple interface.

AWS Lambda and Serverless

  1. What are the key use cases for AWS Lambda?

    • Running event-driven workloads
    • Processing data streams (e.g., AWS Kinesis, DynamoDB streams)
    • Building APIs with AWS API Gateway
    • Automating infrastructure management tasks

  2. How does AWS Lambda handle scaling?

    AWS Lambda automatically scales based on the number of incoming requests or events, creating as many function instances as needed to handle the load.

  3. What are cold starts in AWS Lambda?

    A cold start occurs when a new Lambda instance is initialized due to an increase in load or when the function hasn't been invoked for some time. This can cause a slight delay in execution.

  4. How can you reduce cold start latency in Lambda?

    You can reduce cold starts by optimizing your function’s memory allocation, keeping the function size small, using provisioned concurrency, or keeping the function “warm” by invoking it periodically.

  5. What is provisioned concurrency in Lambda?

    Provisioned concurrency ensures that a set number of Lambda instances are always warm and ready to handle requests, reducing the cold start problem.

AWS Monitoring and Troubleshooting

  1. How do you monitor AWS Lambda functions?

    Use AWS CloudWatch to monitor Lambda functions. CloudWatch provides metrics such as invocation count, duration, error count, and throttles.

  2. What is AWS CloudTrail, and how does it help with auditing?

    AWS CloudTrail logs all API calls made within your AWS account, helping with auditing, compliance, and security monitoring.

  3. How do you troubleshoot failed deployments in AWS CodeDeploy?

    You can troubleshoot failed deployments by checking the deployment logs in AWS CodeDeploy, reviewing application logs in CloudWatch, and verifying your deployment configurations.

  4. What is AWS Trusted Advisor?

    AWS Trusted Advisor is an online resource that provides real-time guidance to help you follow AWS best practices for cost optimization, performance, security, and fault tolerance.

  5. What are CloudWatch Logs, and how do they help with monitoring?

    CloudWatch Logs capture log data from AWS services and applications. They help monitor, troubleshoot, and analyze application and system logs in real-time.

AWS Elastic Load Balancer (ELB)

  1. What is the difference between Application Load Balancer (ALB) and Network Load Balancer (NLB)?

    • ALB operates at the application layer (Layer 7) and is used for routing HTTP/HTTPS traffic.
    • NLB operates at the transport layer (Layer 4) and is used for ultra-low latency and high-throughput connections, handling TCP/UDP traffic.

  2. How does an Application Load Balancer (ALB) handle routing?

    ALB routes incoming traffic based on rules such as URL paths, hostnames, and HTTP headers. It provides advanced features like sticky sessions and SSL termination.

  3. What is SSL termination, and how does ELB handle it?

    SSL termination refers to the process of decrypting SSL traffic at the load balancer level instead of the backend instances. ELB can manage SSL certificates and terminate SSL connections for you.

  4. How do you configure sticky sessions with an Application Load Balancer?

    You can enable sticky sessions (session affinity) for an ALB by configuring a target group to bind a user’s session to a specific backend instance.

  5. What is Cross-Zone Load Balancing?

    Cross-Zone Load Balancing ensures that incoming traffic is distributed evenly across all instances registered to the load balancer, regardless of which availability zone they are in.

AWS Elastic Block Store (EBS) and Databases

  1. What is Amazon EBS?

    Amazon Elastic Block Store (EBS) provides persistent block storage volumes for use with EC2 instances. EBS volumes can be used as primary storage for data that requires frequent updates, like databases or log files.

  2. What are the different types of EBS volumes?

    • General Purpose SSD (gp3/gp2)
    • Provisioned IOPS SSD (io2/io1)
    • Throughput Optimized HDD (st1)
    • Cold HDD (sc1)

  3. What is Amazon RDS?

    Amazon Relational Database Service (RDS) is a managed service that makes it easy to set up, operate, and scale relational databases in the cloud. It supports multiple engines like MySQL, PostgreSQL, MariaDB, and Oracle.

  4. What is Amazon Aurora?

    Amazon Aurora is a fully managed MySQL- and PostgreSQL-compatible relational database that offers performance improvements and high availability.

  5. What is Amazon DynamoDB?

    Amazon DynamoDB is a fully managed NoSQL database service that provides fast and predictable performance with seamless scalability, designed for high-availability applications.

These 100 questions cover a broad range of AWS DevOps topics, from basic concepts to advanced practices. Let me know if you'd like more detailed explanations on any specific topic or have further questions!


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