20+ Devops Consultant Interview Questions and Answers

AWS offers three types of load balancers: Application, Network, and Classic. Auto-Scaling helps to automatically adjust resources based on demand. S3 offers four storage classes: Standard, Intelligent-Tiering, Standard-Infrequent Access, and Glacier.

• AWS offers three types of load balancers: Application, Network, and Classic

• Application Load Balancer operates at Layer 7 of the OSI model and is best suited for HTTP/HTTPS traffic

• Network Load Balancer operates at Layer 4 of the OS...read more

Explanation of DevOps CI/CD flow and Git commands

• DevOps CI/CD flow involves continuous integration, testing, and deployment of code changes

• Git stash temporarily saves changes without committing them

• Git commit permanently saves changes to the repository

• Git merge combines changes from different branches

• Git rebase applies changes from one branch onto another

• Git pull fetches changes from a remote repository and merges them into the local branch

• Git fetch only fetches changes from ...read more

To connect to instances, I will use SSH (Secure Shell) protocol.

• SSH (Secure Shell) protocol is a secure way to connect to instances remotely.

• It provides encrypted communication between the client and the server.

• To connect, I will use SSH client software like OpenSSH or PuTTY.

• I will need the public IP address or hostname of the instance.

• I will authenticate using SSH keys or username/password credentials.

Kubernetes architecture includes master nodes, worker nodes, etcd, kubelet, kube-proxy, and more. Communication between pods is established using a network overlay.

• Kubernetes architecture consists of master nodes, which manage the cluster, and worker nodes, where applications run.

• etcd is a distributed key-value store used for storing cluster data.

• kubelet is an agent that runs on each node and ensures containers are running.

• kube-proxy is a network proxy that maintains network ...read more

Kubernetes pods - difference between deployment and daemonset

• Deployment manages a set of identical pods, ensuring availability and scalability

• DaemonSet ensures that all nodes run a copy of a pod, useful for system-level services

• Deployment is suitable for stateless applications, while DaemonSet is suitable for stateful applications

• Deployment can be used for rolling updates, while DaemonSet is not suitable for rolling updates

Docker commands and concepts comparison

• Run vs entry point: 'docker run' is used to create a new container while 'entrypoint' specifies the command to run when the container starts.

• Copy vs add: 'COPY' is used to copy files from the host to the container while 'ADD' can also fetch files from URLs and extract tarballs.

• Process vs demons: Processes are foreground tasks that run in the container while daemons are background tasks that run continuously.

DevOps CICD experience with cloud and tool proficiency

• Experience implementing Continuous Integration/Continuous Deployment pipelines using tools like Jenkins, Ansible, Git, Docker, Kubernetes

• Proficiency in cloud platforms such as AWS, GCP, Azure, or on-premise cloud environments

• Familiarity with collaboration tools like Confluence, Jira, Bitbucket, GitHub

• Ability to automate tasks using Python scripting

• Hands-on experience with containerization technologies like Docker

Terraform's tfstate file tracks infrastructure; recovery methods exist for corrupted or deleted states.

• Use remote state storage (e.g., S3, Azure Blob) to enable versioning and recovery.

• If the state file is corrupted, check for backups or use 'terraform state pull' to retrieve the latest state.

• In case of deletion, restore from the versioned backup in remote storage or use 'terraform import' to recreate resources.

• Always implement a state locking mechanism to prevent concurrent ...read more

A Dockerfile for Python code with explanations of each command and the difference between ADD & COPY.

• Use a base Python image as the starting point, such as 'python:3.8'.

• Use WORKDIR to set the working directory inside the container.

• Use COPY to add files from the host machine to the container, while ADD can also fetch files from URLs and extract tarballs.

• Use RUN to execute commands during the build process, such as installing dependencies with pip.

• Use CMD to specify the command...read more

Shell script to sort files in descending order

• Use the 'ls' command to list all files in a directory

• Pipe the output of 'ls' to the 'sort' command with the '-r' flag for reverse order

• Example: ls | sort -r

Terraform module is a reusable set of resources that can be used to create infrastructure.

• Terraform modules can be used to create reusable infrastructure code.

• They can be shared across teams and projects.

• Modules can be published to the Terraform Registry for easy access.

• Modules can be parameterized to allow for customization.

• Example: A module for creating an AWS VPC with subnets and security groups.

Software development lifecycle is a process used by software development teams to design, develop, test, and deploy software applications.

• It consists of several phases such as planning, design, development, testing, deployment, and maintenance.

• Each phase has its own set of activities and deliverables.

• Common methodologies used in software development lifecycle include Waterfall, Agile, and DevOps.

• Tools like Jira, Git, Jenkins, and Docker are often used to support the software ...read more

Jenkins pipeline with environment variable

• Define environment variable in Jenkinsfile

• Use 'environment' directive to set environment variables

• Access environment variable using 'env.' syntax

Minimizing downtime can be achieved through proper planning, monitoring, and automation.

• Conduct regular maintenance and updates to prevent system failures

• Implement redundancy and failover mechanisms to ensure continuous operation

• Monitor system performance and proactively address potential issues

• Automate processes to reduce the risk of human error and speed up recovery time

• Have a disaster recovery plan in place to quickly restore services in case of a major outage

A good SCM branching strategy involves clear naming conventions, regular merges, and a well-defined release process.

• Use a naming convention that clearly identifies the purpose of each branch

• Regularly merge changes from development branches into the main branch

• Have a well-defined release process that includes testing and deployment

• Consider using feature toggles to enable/disable new functionality

• Use automation tools to streamline the branching and merging process

Provisioners in Terraform are used to execute scripts on a local or remote machine as part of resource creation or destruction.

• Provisioners can be used to install software, run configuration management tools, or execute scripts on instances created by Terraform.

• There are different types of provisioners such as local-exec, remote-exec, and file.

• Provisioners should be used sparingly as they can make Terraform configurations less predictable and harder to maintain.

DevOps engineers are responsible for automating, monitoring, and maintaining the infrastructure and deployment pipelines.

• Automating build and deployment processes using tools like Jenkins, GitLab CI/CD, or CircleCI

• Monitoring system performance and availability using tools like Prometheus, Grafana, or ELK stack

• Collaborating with development and operations teams to streamline processes and improve efficiency

• Managing infrastructure as code using tools like Terraform or Ansible

• Im...read more

DevOps principles focus on collaboration, automation, measurement, and continuous improvement.

• Collaboration between development and operations teams

• Automation of processes to increase efficiency and reduce errors

• Measurement of performance metrics to identify areas for improvement

• Continuous improvement through feedback and iteration

• Use of tools like Docker, Kubernetes, and Jenkins to support DevOps practices

Subnets on virtual machines refer to dividing a network into smaller segments for better organization and security.

• Subnets help in managing network traffic efficiently

• Each subnet can have its own security policies and access controls

• Subnets can be used to isolate different parts of a network for security reasons

VNet peering allows connecting virtual networks in Azure

• VNet peering enables resources in different virtual networks to communicate securely

• Traffic between peered VNets stays on the Microsoft backbone network

• No public internet, gateways, or encryption needed for communication between peered VNets

Terraform is an open-source infrastructure as code software tool created by HashiCorp.

• Terraform allows users to define and provision data center infrastructure using a declarative configuration language.

• It supports multiple cloud providers such as AWS, Azure, and Google Cloud Platform.

• Terraform uses a 'plan and apply' workflow to make changes to infrastructure.

• Infrastructure code written in Terraform is versioned and can be shared and reused.

• Terraform state files store the cu...read more

CI/CD branching process involves strategies for managing code changes and deployments efficiently.

• Feature Branching: Each new feature is developed in its own branch, e.g., 'feature/user-auth'.

• Release Branching: A branch is created for each release, e.g., 'release/v1.0'.

• Hotfix Branching: Critical fixes are made in a separate branch, e.g., 'hotfix/issue-123'.

• Main Branch: The 'main' or 'master' branch always contains production-ready code.

• Pull Requests: Code changes are merged b...read more