900+ Devops Engineer Interview Questions and Answers

I have faced errors such as resource conflicts, syntax errors, and provider version mismatches while applying Terraform code.

• Resource conflicts occur when multiple resources are trying to create the same resource at the same time.

• Syntax errors can occur due to incorrect syntax in the Terraform code, such as missing brackets or incorrect attribute names.

• Provider version mismatches can occur when the Terraform code is written for a specific provider version but a different vers...read more

Deployment strategies ensure efficient software delivery while maintaining system stability and security.

• Blue-Green Deployment: Two identical environments (blue and green) to reduce downtime during updates.

• Canary Releases: Gradually roll out changes to a small subset of users before full deployment.

• Rolling Updates: Update instances in batches to minimize impact on users.

• Recreate Strategy: Stop the old version and deploy the new version, suitable for stateless applications.

• A/B...read more

To check listen ports, use netstat command in terminal.

• Open terminal/command prompt

• Type 'netstat -tuln' command

• This will display all the listening ports on the system

Questions related to implementation and performance of Hadoop cluster.

• SSL implementation for Hadoop services involves generating SSL certificates and configuring SSL/TLS protocols for secure communication between Hadoop components.

• Kerberos implementation for Hadoop components involves setting up a Kerberos KDC, creating principals and keytabs, and configuring Hadoop services to use Kerberos authentication.

• Performance benchmarking of Hadoop cluster involves measuring various m...read more

Feature branching and task branching are strategies used in version control systems to manage development tasks.

• Feature branching involves creating a separate branch for each new feature being developed, allowing for isolation and independent development.

• Task branching is similar to feature branching but is used for smaller tasks or bug fixes.

• Both feature branching and task branching help in organizing and managing code changes effectively.

• Example: Creating a feature branch '...read more

Docker multistage is a feature that allows you to build multiple Docker images in a single Dockerfile.

• Docker multistage helps in reducing the size of the final image by using intermediate images for different stages of the build process.

• It allows you to separate the build environment from the runtime environment, improving security and efficiency.

• Each stage in a multistage build can be named and used to copy artifacts from one stage to another, without including unnecessary d...read more

Packages in Lambda are libraries or modules that can be used to extend the functionality of the code. Environment variables are used to store sensitive data.

• Packages can be installed using pip or uploaded as a zip file

• Environment variables can be set in the Lambda console or using AWS CLI

• They can be accessed in the code using os.environ['variable_name']

• Examples of sensitive data that can be stored in env variables are database credentials, API keys, and passwords

SQL query optimization techniques improve performance by reducing query execution time.

• Use indexes to speed up data retrieval

• Avoid using SELECT * and only retrieve necessary columns

• Optimize joins by using appropriate join types (e.g. INNER JOIN, LEFT JOIN)

• Use WHERE clause to filter data early in the query

• Avoid using subqueries if possible

Kubernetes is an open-source container orchestration platform that automates deployment, scaling, and management of containerized applications.

• Kubernetes is used to manage containerized applications across multiple hosts.

• It provides a platform for automating deployment, scaling, and operations of application containers.

• Kubernetes architecture consists of a master node and worker nodes.

• The master node manages the cluster and schedules workloads to the worker nodes.

• Worker nodes...read more

My strategy for Kubernetes cluster is to ensure high availability, scalability, and efficient resource utilization.

• Implementing auto-scaling to handle sudden spikes in traffic

• Using Kubernetes' built-in features like horizontal pod autoscaling and cluster autoscaling

• Ensuring proper resource allocation and utilization through resource quotas and limits

• Implementing rolling updates to minimize downtime

• Using Kubernetes' built-in monitoring and logging tools to identify and trouble...read more

Filter command in Linux is used to filter out specific data from a file or output.

• The basic syntax of the filter command is 'command | filter'.

• Commonly used filter commands are grep, sed, awk, cut, sort, uniq, etc.

• grep is used to search for a specific pattern in a file or output.

• sed is used to perform text transformations on a file or output.

• awk is used to process and manipulate text data.

• cut is used to extract specific columns from a file or output.

• sort is used to sort the l...read more

DevOps is a software development methodology that emphasizes collaboration and communication between development and operations teams.

• DevOps involves continuous integration, delivery, and deployment

• Phases of DevOps include planning, coding, building, testing, releasing, deploying, operating, and monitoring

• DevOps tools include Git, Jenkins, Docker, Kubernetes, and more

git fetch vs git pull and git clone vs git remote

• git fetch downloads the changes from the remote repository but does not merge them with the local branch

• git pull downloads the changes and merges them with the local branch

• git clone creates a copy of the remote repository on the local machine

• git remote is used to manage the remote repositories that a local repository is connected to

Kubernetes Load Balancing is a method to distribute incoming network traffic across multiple pods in a Kubernetes cluster.

• Kubernetes Load Balancer service type automatically creates a cloud provider load balancer.

• It helps in scaling applications by distributing traffic evenly across multiple pods.

• Load balancing ensures high availability and reliability of applications running in a Kubernetes cluster.

Ruby program to check if a directory exists

• Use the File.directory? method in Ruby to check if a directory exists

• Provide the directory path as an argument to the method

• Return true if the directory exists, false otherwise

Control plane components in Kubernetes manage the cluster and make decisions about the state of the cluster.

• Control Manager: Ensures that the desired state of the cluster matches the actual state.

• Scheduler: Assigns workloads to nodes based on resource availability and constraints.

• API Server: Acts as the front-end for the Kubernetes control plane and is the primary interface for users and other components.

• etcd: Consistent and highly-available key-value store used as Kubernetes...read more

To take backup of pipeline in Azure DevOps, follow these steps:

• Go to the pipeline you want to backup

• Click on the three dots on the top right corner

• Select 'Export'

• Choose the format you want to export the pipeline in

• Save the file in a secure location

Injections and attacks can be handled by implementing security measures and regularly updating software.

• Implement security measures such as firewalls, intrusion detection systems, and access controls

• Regularly update software and apply security patches

• Conduct regular security audits and penetration testing

• Train employees on security best practices and conduct background checks

• Use encryption to protect sensitive data

• Monitor network traffic for suspicious activity

VPC pairing is a process of connecting two VPCs to enable communication between them.

• VPC pairing allows resources in one VPC to communicate with resources in another VPC.

• The process involves creating a VPC peering connection between the two VPCs.

• Both VPCs must have non-overlapping IP address ranges.

• VPC pairing can be used to share resources, such as databases or file systems, between VPCs.

• VPC pairing can also be used to create a hub-and-spoke network topology.

• VPC pairing can ...read more

CI/CD automates software delivery; GitHub is a code repository; DevOps integrates development and operations; Azure DevOps supports CI/CD.

• CI/CD stands for Continuous Integration and Continuous Deployment, streamlining software development and delivery.

• GitHub is a platform for version control and collaboration, allowing multiple developers to work on projects simultaneously.

• DevOps is a cultural and technical movement that emphasizes collaboration between development and operat...read more

I have experience with various devops tools and technologies.

• Continuous Integration/Continuous Deployment (CI/CD) tools such as Jenkins, GitLab CI/CD, Travis CI

• Configuration management tools such as Ansible, Chef, Puppet

• Containerization tools such as Docker, Kubernetes

• Infrastructure as Code (IaC) tools such as Terraform, CloudFormation

• Monitoring and logging tools such as ELK Stack, Prometheus, Grafana

• Version control tools such as Git

• Collaboration tools such as Jira, Confluenc...read more

Creating a pipeline through script involves defining stages, tasks, and triggers in a script file.

• Define stages for each step in the pipeline

• Define tasks for each stage, such as building, testing, and deploying

• Define triggers for each stage, such as manual or automatic triggers

• Use a scripting language such as YAML or JSON to define the pipeline

• Examples: Jenkinsfile for Jenkins, azure-pipelines.yml for Azure DevOps

The VPN port used for UDP is typically 500.

• The VPN port used for UDP is usually port 500.

• UDP is a protocol that allows for faster transmission of data but does not guarantee delivery or order of packets.

• Port 500 is commonly used for IPsec VPNs, which provide secure communication over the internet.

• Other VPN protocols may use different ports for UDP, so it's important to check the specific configuration.

Stateful applications store data while stateless applications do not.

• Stateful applications maintain a record of previous interactions and require persistent storage.

• Stateless applications do not store data and can be easily scaled horizontally.

• Stateful applications are more complex and require more resources than stateless applications.

• Examples of stateful applications include databases and messaging systems, while stateless applications include web servers and load balancers...read more

To make a call from one namespace to another in AKS environment, use the fully qualified domain name (FQDN) of the service.

• Use the FQDN of the service to make a call from one namespace to another in AKS environment

• The FQDN should include the namespace and service name, for example: myservice.mynamespace.svc.cluster.local

• Ensure that the service is exposed within the cluster and has a stable IP address

• Use the appropriate network policies to allow traffic between namespaces if n...read more

Explanation of OOPs and Array with an example

• OOPs is a programming paradigm that uses objects to represent real-world entities

• Array is a collection of similar data types stored in contiguous memory locations

• Example: A car object in OOPs can have properties like color, model, and methods like start, stop

• Example: An array of integers [1, 2, 3, 4, 5] can be used to perform mathematical operations

Ansible is a configuration management and automation tool, while Terraform is an infrastructure provisioning tool.

• Ansible is used for configuration management, application deployment, and task automation.

• Terraform is used for infrastructure provisioning and managing cloud resources.

• Ansible uses YAML-based playbooks to define tasks and configurations, while Terraform uses HCL (HashiCorp Configuration Language) to define infrastructure as code.

• Ansible is agentless, meaning it d...read more

Docker is a containerization platform for packaging, distributing, and running applications. Kubernetes is a container orchestration tool for managing containerized applications.

• Docker allows you to package an application and its dependencies into a container for easy deployment.

• Kubernetes automates the deployment, scaling, and management of containerized applications.

• Kubernetes provides features like auto-scaling, self-healing, and load balancing, which Docker alone does not...read more

To create a dashboard and set up alerts in Grafana or AppDynamics, you can use the following steps:

• 1. Log in to Grafana or AppDynamics and navigate to the dashboard section.

• 2. Click on 'Create Dashboard' and choose the type of visualization you want to add (e.g. graph, table, gauge).

• 3. Configure the data source for your dashboard (e.g. Prometheus, InfluxDB, AppDynamics).

• 4. Add panels to your dashboard by selecting the metrics you want to display.

• 5. Customize the appearance of...read more

Automate image version iteration by using CI/CD pipelines and version control systems.

• Use CI/CD pipelines to automatically build and deploy new versions of the image

• Integrate version control systems like Git to manage image versions

• Utilize tools like Jenkins, GitLab CI/CD, or CircleCI for automation

• Implement versioning schemes like semantic versioning (e.g. 1.0.0, 1.0.1, 1.1.0)

Yes, it is possible to attach multiple instances to a single EBS volume.

• This is achieved by using Amazon EBS Multi-Attach feature.

• It allows multiple EC2 instances to attach to a single EBS volume simultaneously.

• This feature is useful for applications that require high availability and shared access to data.

• However, not all EC2 instance types support multi-attach.

• It is important to ensure that the application is designed to handle concurrent access to the shared data.

The Linux boot process involves several stages including BIOS, bootloader, kernel initialization, and user space initialization.

• BIOS (Basic Input/Output System) performs hardware initialization and loads the bootloader

• Bootloader (such as GRUB) loads the Linux kernel into memory and starts its execution

• Kernel initializes devices, mounts the root filesystem, and starts the init process

• Init process (systemd or SysVinit) initializes user space components and services

Docker image has 3 layers: Base, Dependencies and Application.

• Base layer contains the OS and other system-level libraries.

• Dependencies layer contains the libraries and packages required by the application.

• Application layer contains the code and files specific to the application.

• Each layer is read-only and builds on top of the previous layer.

• Changes made to one layer do not affect the other layers.

• This layering approach makes Docker images lightweight and easy to share.

For handling live sale load for load balancing, I would use a combination of horizontal and vertical scaling with a load balancer.

• Implement horizontal scaling by adding more instances of the application to distribute the load evenly.

• Utilize a load balancer to evenly distribute incoming traffic across multiple instances.

• Implement vertical scaling by increasing the resources (CPU, memory) of individual instances to handle increased load.

• Use auto-scaling to automatically adjust ...read more

Autoscaling methods in Kubernetes include Horizontal Pod Autoscaler (HPA), Cluster Autoscaler, and Vertical Pod Autoscaler (VPA).

• Horizontal Pod Autoscaler (HPA) scales the number of pods based on CPU utilization or custom metrics

• Cluster Autoscaler scales the number of nodes in a cluster based on resource utilization

• Vertical Pod Autoscaler (VPA) adjusts the resource requests and limits of containers based on usage patterns

• HPA can be used with custom metrics like queue length o...read more

Terraform modules are reusable components used to organize and manage resources in Terraform configurations.

• Modules help in organizing Terraform configurations into reusable components

• They allow for better code reusability and maintainability

• Modules can be shared and reused across different Terraform configurations

• They encapsulate a set of resources and their configurations

• Modules can have input and output variables for customization

Setting up a VPC in Azure involves creating a virtual network, subnets, and configuring security groups.

• Create a virtual network in the Azure portal

• Define subnets within the virtual network

• Configure network security groups to control inbound and outbound traffic

• Establish peering connections with other VPCs if needed

To run AWS EC2 and VPC, create instances in EC2 and configure security groups in VPC for instance protection.

• Create EC2 instances by selecting AMI, instance type, and configuring storage.

• Set up VPC with subnets, route tables, and internet gateways for network isolation.

• Configure security groups in VPC to control inbound and outbound traffic to instances.

• Use IAM roles for secure access to AWS resources.

• Implement encryption for data at rest and in transit for enhanced security.

To access an EC2 instance without a PEM key, you can use AWS Systems Manager Session Manager or create a new key pair and attach it to the instance. There are different types of S3 storage classes such as Standard, Intelligent-Tiering, Glacier, etc.

• Use AWS Systems Manager Session Manager to access EC2 without a PEM key

• Create a new key pair and attach it to the EC2 instance

• S3 storage classes include Standard, Intelligent-Tiering, Glacier, etc.

Build a Docker image to convert HTML page link to PDF file

• Create a Dockerfile with necessary dependencies like wkhtmltopdf

• Install wkhtmltopdf in the Docker image

• Write a script to convert HTML link to PDF using wkhtmltopdf command

• Build the Docker image with the script included

• Run the Docker container to convert HTML link to PDF

Setting up Piggymetrics project on Github and Dockerhub

• Clone the Piggymetrics project from Github

• Create a Dockerfile to build the project into a Docker image

• Push the Docker image to Dockerhub

• Ensure the project runs successfully in a Docker container

Cost optimization in DevOps is achieved through efficient resource utilization, automation, and continuous monitoring.

• Implementing auto-scaling to dynamically adjust resources based on demand

• Using containerization to maximize resource utilization and reduce costs

• Leveraging cloud services for pay-as-you-go pricing model

• Implementing cost monitoring tools to identify and eliminate wasteful spending

• Optimizing code and infrastructure for efficiency and performance

• Consolidating and...read more

To schedule backups in a server using a script, you can use a cron job.

• Create a backup script that includes the necessary commands to backup the desired files or directories.

• Set the script to be executable using the chmod command.

• Create a cron job using the crontab command that specifies the frequency and timing of the backups.

• Test the backup script and cron job to ensure they are working correctly.

Environments in Azure DevOps are logical groups of resources where code is deployed and tested.

• Environments can be created for different stages of the development process, such as development, testing, staging, and production.

• Each environment can have its own set of resources, such as virtual machines, databases, and storage accounts.

• Environments can be configured to automatically deploy code from a pipeline or manually triggered.

• Examples of environments include 'Dev', 'QA', ...read more

DevOps engineers are responsible for bridging the gap between development and operations teams.

• Automating deployment processes

• Monitoring system performance

• Collaborating with development and operations teams

• Ensuring system security and reliability

• Implementing continuous integration and delivery

• Managing infrastructure and configuration

• Troubleshooting issues and providing solutions

I prefer to discuss compensation after understanding the role and responsibilities.

• I am open to negotiation based on the job requirements

• I am looking for a fair and competitive salary

• I am more interested in the opportunity and growth potential than just the salary

• I am willing to consider other benefits such as health insurance, retirement plans, etc.

A Dockerfile is a text document that contains all the commands a user could call on the command line to assemble an image.

• Use 'FROM' to specify the base image

• Use 'RUN' to execute commands in the container

• Use 'COPY' to copy files from the host to the container

• Use 'CMD' to specify the command to run when the container starts

• Use 'EXPOSE' to expose ports

• Use 'WORKDIR' to set the working directory

• Use 'ENV' to set environment variables