What is DevOps, and why is it important?
DevOps is a set of practices that combines software development (Dev) and IT operations (Ops) to automate and streamline the software delivery process. It aims to increase collaboration, improve efficiency, and shorten development cycles.
Explain the key principles of DevOps.
The key principles of DevOps include collaboration, automation, continuous integration, continuous delivery/deployment (CI/CD), monitoring, and feedback. These principles emphasize communication, automation, and the rapid delivery of high-quality software.
What is the role of version control systems in DevOps, and name some popular version control tools.
Version control systems (VCS) track changes to source code and other files, enabling collaboration and tracking of changes over time. Popular VCS tools include Git, Subversion (SVN), and Mercurial.
Explain continuous integration (CI) and continuous delivery (CD) in DevOps.
Continuous Integration (CI): Developers frequently merge their code changes into a shared repository, where automated tests are run to detect integration issues early.
Continuous Delivery (CD): Automated deployments to production or staging environments are possible at any time, but manual approval may be required for release.
What are the key benefits of using containerization in DevOps?
Containerization (e.g., Docker) provides benefits such as consistency, portability, and isolation. Containers package applications and their dependencies, making it easier to deploy and scale applications across different environments.
Explain the concept of Infrastructure as Code (IaC).
Infrastructure as Code is the practice of defining and provisioning infrastructure using code and automation scripts. It allows for consistent, version-controlled, and repeatable infrastructure deployments.
What is the purpose of configuration management tools in DevOps, and name some examples.
Configuration management tools (e.g., Ansible, Puppet, Chef) automate the management and configuration of servers and infrastructure. They ensure consistency and reduce manual configuration errors.
What is continuous monitoring in DevOps, and why is it important?
Continuous monitoring involves real-time tracking and analysis of application and infrastructure performance, security, and health. It helps identify issues early and ensures that systems meet performance and security requirements.
What is the role of DevOps in the context of security (DevSecOps)?
DevOps integrates security practices into the software development and deployment process. DevSecOps emphasizes security early in the development lifecycle, automates security testing, and encourages collaboration between security and development teams.
Explain the concept of “shift-left” in DevOps.
“Shift-left” refers to the practice of moving tasks such as testing, security, and quality assurance earlier in the software development lifecycle, rather than addressing them late in production. This helps catch and fix issues sooner.
What is Blue-Green Deployment, and how does it work in DevOps?
Blue-Green Deployment involves maintaining two identical environments: the “blue” (current) and “green” (new) environments. The switch between them is seamless, allowing for easy rollback if issues are detected in the “green” environment.
What is the role of DevOps in cloud computing and serverless architectures?
DevOps practices are well-suited to cloud computing and serverless architectures because they facilitate the automated provisioning, scaling, and management of resources, making it easier to develop and deploy applications in these environments.
How do you handle versioning of artifacts in a CI/CD pipeline?
Artifacts (e.g., software packages, binaries) should be versioned and stored in a repository (e.g., Nexus, JFrog Artifactory). Versioning ensures traceability and repeatability of deployments in the CI/CD pipeline.
Explain the concept of “immutable infrastructure” in DevOps.
Immutable infrastructure involves creating and deploying infrastructure components (e.g., VMs, containers) as static, unchangeable artifacts. When changes are needed, new instances are deployed instead of modifying existing ones.
How do you measure the success of a DevOps implementation?
Success can be measured through key performance indicators (KPIs) such as reduced lead time, increased deployment frequency, lower error rates, and improved collaboration between development and operations teams.
What is DevOps, and how does it differ from traditional software development methodologies?
– DevOps is a set of practices that aim to automate and integrate the processes of software development and IT operations to deliver software more quickly and reliably. Unlike traditional methods, DevOps emphasizes collaboration, automation, and continuous delivery.
Explain the purpose of version control systems in DevOps.
– Version control systems (VCS) like Git are essential in DevOps to manage source code, track changes, collaborate on code, and enable continuous integration. They help maintain a history of code changes and facilitate collaboration among development and operations teams.
What is Continuous Integration (CI), and how does Jenkins facilitate CI?
– CI is a DevOps practice where code changes are frequently integrated into a shared repository and automatically tested. Jenkins is a popular CI tool that automates building, testing, and deploying code changes. It ensures that new code is continually integrated and verified.
What is Continuous Deployment (CD), and how does it differ from Continuous Delivery?
– Continuous Deployment (CD) automates the deployment of code changes directly to production, with minimal human intervention. Continuous Delivery (CD) involves automating the delivery of code changes to a staging or pre-production environment for manual approval before going to production.
Explain the role of Docker in containerization and how it benefits DevOps.
– Docker is a containerization platform that packages applications and their dependencies into lightweight containers. DevOps benefits from Docker as it provides consistency, isolation, and portability, allowing for easy deployment and scaling of applications.
What is Configuration Management, and how does Ansible help in this area?
– Configuration Management is the practice of automating and managing the configuration of servers and infrastructure. Ansible is a configuration management tool that allows DevOps teams to define and apply infrastructure configurations as code, ensuring consistency and repeatability.
What is Infrastructure as Code (IaC), and how does Terraform fit into DevOps?
– IaC is the practice of managing and provisioning infrastructure using code. Terraform is an IaC tool that allows DevOps teams to define infrastructure in code and automatically create, update, and destroy resources. It enhances infrastructure agility and consistency.
Explain the role of monitoring and alerting tools like Prometheus in DevOps.
– Monitoring tools like Prometheus track the health and performance of applications and infrastructure. They generate alerts in response to anomalies, helping DevOps teams proactively identify and address issues to maintain system reliability.
What is Continuous Testing in DevOps, and how can tools like Selenium be used for it?
– Continuous Testing involves automating the testing process throughout the software development lifecycle. Selenium is a popular tool for automated testing of web applications. It allows DevOps teams to perform regression and functional testing consistently.
How does GitOps work, and what are the key benefits?
– GitOps is a DevOps methodology that leverages Git repositories as the source of truth for infrastructure and application deployments. It promotes versioning, collaboration, and traceability while ensuring that changes are made through code, leading to automation and repeatability.
Explain the purpose of a CI/CD pipeline and how Jenkins can be used to create one.
– A CI/CD pipeline automates the software delivery process, from code integration to deployment. Jenkins can be used to create CI/CD pipelines by orchestrating various stages such as building, testing, packaging, and deployment.
What are container orchestration tools, and how does Kubernetes facilitate container management?
– Container orchestration tools manage the deployment, scaling, and operation of containers. Kubernetes is a widely used orchestration platform in DevOps, providing features for automating containerized applications, load balancing, and high availability.
What is APM (Application Performance Monitoring), and why is it important in DevOps?
– APM tools like New Relic or AppDynamics provide real-time insights into application performance, helping DevOps teams quickly identify and resolve performance issues, optimize resources, and enhance user experience.
Explain the concept of DevSecOps and the role of security tools in the DevOps pipeline.
– DevSecOps integrates security practices into the DevOps pipeline. Security tools like OWASP ZAP or SonarQube help automate security checks, code scanning, and vulnerability assessment, ensuring that security is part of the development process.
What is the purpose of a centralized logging and monitoring system like ELK (Elasticsearch, Logstash, and Kibana) in DevOps?
– A centralized logging and monitoring system like ELK collects and analyzes log data from various sources, helping DevOps teams troubleshoot issues, track application performance, and gain insights into system behavior for continuous improvement.
What is Version control?
Version control is a system that records changes to a file or set of files over time so that you can recall specific versions later.
What are Containers?
Containers are a form of lightweight virtualization, heavier than ‘chroot’ but lighter than ‘hypervisors’. They provide isolation among processes while using the same kernel as the host machine, and ‘cgroups’ functionality within the kernel.
What is Continuous Delivery?
It is the practice of delivering the software for testing as soon as it is built by CI (Continuous Integration) servers.
What are the uses of Version control?
Below are some of the common uses of version control:
Revert files back to a previous state.
Revert the entire project back to a previous state.
Compare changes over time.
See who last modified something that might be causing a problem.
Who introduced an issue and when.
What are the core operations of DevOps in terms of development and Infrastructure?
The core operations of DevOps are application development, code developing, code coverage, unit testing, packaging, deployment with infrastructure, provisioning, configuration, orchestration, and deployment.
Can one consider DevOps as an Agile methodology?
DevOps can be considered complementary to the agile methodology, but not completely similar.
Name some of the top tools used in DevOps? What are the tools that you have used?
Some of the common tools are – Docker, Git, Selenium, Puppet, Nagios, and Chef.
What is Git?
Git is a Distributed Version Control system (DVCS). It can track changes to a file and allows you to revert back to any particular change.
In Git how do you revert a commit that has already been pushed and made public?
It can be done in two ways:
By removing or fixing the bad file in a new commit and pushing it to the remote repository. Once the necessary changes to the file have been made, commit it to the remote repository. Use: git commit -m “commit message”
By creating a new commit that undoes all changes that were made in the bad commit. To do this, use command: git revert <name of bad commit>
What is Git bisect?
Git bisect is used to find the commit that introduced a bug by using binary search.
Why do you need a Continuous Integration of Dev & Testing?
Continuous Integration of Dev and Testing improves the quality of software and reduces the time taken to deliver it, by replacing the traditional practice of testing after completing all development.
Which is the most popular scripting language in DevOps?
Python.
What is Vagrant, and what is it used for?
A vagrant is a tool that can create and manage virtualized (or containerized) environments for testing and developing software.
What are post-mortem meetings?
Post mortem meetings discuss what went wrong and what steps should be taken so that failure doesn’t happen again.
What is meant by Continuous Integration?
It is a development practice that requires developers to integrate code into a shared repository several times daily.
How to automate Testing in the DevOps lifecycle?
Developers are obliged to commit all source code changes to a shared DevOps repository.
Every time a change is made in the code, Jenkins-like Continuous Integration tools will grab it from this common repository and deploy it for Continuous Testing, which is done by tools like Selenium.
Why is Continuous Testing important for DevOps?
Any modification to the code may be tested immediately with Continuous Testing. This prevents concerns like quality issues and releases delays that might occur whenever big-bang testing is delayed until the end of the cycle. In this way, Continuous Testing allows for high-quality and more frequent releases.
What are the key elements of Continuous Testing tools?
Continuous Testing key elements are:
Test Optimization: It guarantees that tests produce reliable results and actionable information. Test Data Management, Test Optimization Management, and Test Maintenance are examples of aspects.
Advanced Analysis: In order to avoid problems from occurring in the first place and to achieve more within each iteration, it employs automation in areas like scope assessment/prioritization, changes effect analysis, and static code analysis.
Policy Analysis: It guarantees that all processes are in line with the organization’s changing business needs and that all compliance requirements are met.
Risk Assessment: Test coverage optimization, technical debt, risk mitigation duties, and quality evaluation are all covered to guarantee the build is ready to move on to the next stage.
Service Virtualization: Ensures that real-world testing scenarios are available. Service visualisation provides access to a virtual representation of the needed testing phases, ensuring its availability and reducing the time spent setting up the test environment.
Requirements Traceability: It guarantees that no rework is necessary and real criteria are met. To determine which needs require additional validation, are in jeopardy and performing as expected, an object evaluation is used.
Explain the difference between a centralized and distributed version control system (VCS).
Centralized Version Control System:
All file versions are stored on a central server
No developer has a copy of all files on a local system
If the central server crashes, all data from the project will be lost
Distributed Control System:
Every developer has a copy of all versions of the code on their systems
Enables team members to work offline and does not rely on a single location for backups
There is no threat, even if the server crashes
How do you push a file from your local system to the GitHub repository using Git?
First, connect the local repository to your remote repository:
git remote add origin [copied web address]
// Ex: git remote add origin https://github.com/Simplilearn-github/test.git
Second, push your file to the remote repository:
git push origin master
How is a bare repository different from the standard way of initializing a Git repository?
Using the standard method:
git init
You create a working directory with git init
A .git subfolder is created with all the git-related revision history
Using the bare way:
git init –bare
It does not contain any working or checked out a copy of source files
Bare repositories store git revision history in the root folder of your repository, instead of the .git subfolder
What is the process for reverting a commit that has already been pushed and made public?
There are two ways that you can revert a commit:
- Remove or fix the bad file in a new commit and push it to the remote repository. Then commit it to the remote repository using:
git commit –m “commit message”
- Create a new commit that undoes all the changes that were made in the bad commit. Use the following command:
git revert <commit id>
Example: git revert 56de0938f
What is Git stash?
A developer working with a current branch wants to switch to another branch to work on something else, but the developer doesn’t want to commit changes to your unfinished work. The solution to this issue is Git stash. Git stash takes your modified tracked files and saves them on a stack of unfinished changes that you can reapply at any time.
Explain the concept of branching in Git.
Suppose you are working on an application, and you want to add a new feature to the app. You can create a new branch and build the new feature on that branch.
By default, you always work on the master branch
The circles on the branch represent various commits made on the branch
After you are done with all the changes, you can merge it with the master branch
What is the difference between Git Merge and Git Rebase?
Suppose you are working on a new feature in a dedicated branch, and another team member updates the master branch with new commits. You can use these two functions:
Git Merge:
To incorporate the new commits into your feature branch, use Git merge.
Creates an extra merge commit every time you need to incorporate changes
But, it pollutes your feature branch history
Git Rebase:
As an alternative to merging, you can rebase the feature branch on to master.
Incorporates all the new commits in the master branch
It creates new commits for every commit in the original branch and rewrites project history
How do you find a list of files that have been changed in a particular commit?
The command to get a list of files that have been changed in a particular commit is:
git diff-tree –r {commit hash}
Example: git diff-tree –r 87e673f21b
-r flag instructs the command to list individual files
commit hash will list all the files that were changed or added in that commit
What is Jenkinsfile?
Jenkinsfile contains the definition of a Jenkins pipeline and is checked into the source control repository. It is a text file.
It allows code review and iteration on the pipeline.
It permits an audit trail for the pipeline.
There is a single source of truth for the pipeline, which can be viewed and edited.
What concepts are key aspects of the Jenkins pipeline?
Pipeline: User-defined model of a CD pipeline. The pipeline’s code defines the entire build process, which includes building, testing, and delivering an application
Node: A machine that is part of the Jenkins environment and capable of executing a pipeline
Step: A single task that tells Jenkins what to do at a particular point in time
Stage: Defines a conceptually distinct subset of tasks performed through the entire pipeline (build, test, deploy stages)
How can you copy Jenkins from one server to another?
Move the job from one Jenkins installation to another by copying the corresponding job directory.
Create a copy of an existing job by making a clone of a job directory with a different name.
Rename an existing job by renaming a directory.
Name three security mechanisms Jenkins uses to authenticate users.
Jenkins uses an internal database to store user data and credentials.
Jenkins can use the Lightweight Directory Access Protocol (LDAP) server to authenticate users.
Jenkins can be configured to employ the authentication mechanism that the deployed application server uses.
How is DevOps different from agile methodology?
DevOps is a culture that allows the development and the operations team to work together. This results in continuous development, testing, integration, deployment, and monitoring of the software throughout the lifecycle.
Agile is a software development methodology that focuses on iterative, incremental, small, and rapid releases of software, along with customer feedback. It addresses gaps and conflicts between the customer and developers.
What is Continuous Testing?
Continuous Testing constitutes the running of automated tests as part of the software delivery pipeline to provide instant feedback on the business risks present in the most recent release. In order to prevent problems in step-switching in the Software delivery life-cycle and to allow Development teams to receive immediate feedback, every build is continually tested in this manner. This results in a significant increase in speed in a developer’s productivity as it eliminates the requirement for re-running all the tests after each update and project re-building.
Which are some of the most popular DevOps tools?
The most popular DevOps tools include:
Selenium
Puppet
Chef
Git
Jenkins
Ansible
Docker
What are the different phases in DevOps?
The various phases of the DevOps lifecycle are as follows:
Plan: Initially, there should be a plan for the type of application that needs to be developed. Getting a rough picture of the development process is always a good idea.
Code: The application is coded as per the end-user requirements.
Build: Build the application by integrating various codes formed in the previous steps.
Test: This is the most crucial step of the application development. Test the application and rebuild, if necessary.
Integrate: Multiple codes from different programmers are integrated into one.
Deploy: Code is deployed into a cloud environment for further usage. It is ensured that any new changes do not affect the functioning of a high traffic website.
Operate: Operations are performed on the code if required.
Monitor: Application performance is monitored. Changes are made to meet the end-user requirements.
Mention some of the core benefits of DevOps.
The core benefits of DevOps are as follows:
Technical benefits
Continuous software delivery
Less complex problems to manage
Early detection and faster correction of defects
Business benefits
Faster delivery of features
Stable operating environments
Improved communication and collaboration between the teams
How will you approach a project that needs to implement DevOps?
The following standard approaches can be used to implement DevOps in a specific project:
Stage 1
An assessment of the existing process and implementation for about two to three weeks to identify areas of improvement so that the team can create a road map for the implementation.
Stage 2
Create a proof of concept (PoC). Once it is accepted and approved, the team can start on the actual implementation and roll-out of the project plan.
Stage 3
The project is now ready for implementing DevOps by using version control/integration/testing/deployment/delivery and monitoring followed step by step.
By following the proper steps for version control, integration, testing, deployment, delivery, and monitoring, the project is now ready for DevOps implementation.
What is Automation Testing?
Test automation or manual testing Automation is the process of automating a manual procedure in order to test an application or system. Automation testing entails the use of independent testing tools that allow you to develop test scripts that can be run repeatedly without the need for human interaction.
What is the role of configuration management in DevOps?
Enables management of and changes to multiple systems.
Standardizes resource configurations, which in turn, manage IT infrastructure.
It helps with the administration and management of multiple servers and maintains the integrity of the entire infrastructure.
How does continuous monitoring help you maintain the entire architecture of the system?
Continuous monitoring in DevOps is a process of detecting, identifying, and reporting any faults or threats in the entire infrastructure of the system.
Ensures that all services, applications, and resources are running on the servers properly.
Monitors the status of servers and determines if applications are working correctly or not.
Enables continuous audit, transaction inspection, and controlled monitoring.
What is the role of AWS in DevOps?
AWS has the following role in DevOps:
Flexible services: Provides ready-to-use, flexible services without the need to install or set up the software.
Built for scale: You can manage a single instance or scale to thousands using AWS services.
Automation: AWS lets you automate tasks and processes, giving you more time to innovate
Secure: Using AWS Identity and Access Management (IAM), you can set user permissions and policies.
Large partner ecosystem: AWS supports a large ecosystem of partners that integrate with and extend AWS services.
Name three important DevOps KPIs.
The three important KPIs are as follows:
Meantime to failure recovery: This is the average time taken to recover from a failure.
Deployment frequency: The frequency in which the deployment occurs.
Percentage of failed deployments: The number of times the deployment fails.
Explain the term “Infrastructure as Code” (IaC) as it relates to configuration management.
Writing code to manage configuration, deployment, and automatic provisioning.
Managing data centers with machine-readable definition files, rather than physical hardware configuration.
Ensuring all your servers and other infrastructure components are provisioned consistently and effortlessly.
Administering cloud computing environments, also known as infrastructure as a service (IaaS).
How is IaC implemented using AWS?
Start by talking about the age-old mechanisms of writing commands onto script files and testing them in a separate environment before deployment and how this approach is being replaced by IaC. Similar to the codes written for other services, with the help of AWS, IaC allows developers to write, test, and maintain infrastructure entities in a descriptive manner, using formats such as JSON or YAML. This enables easier development and faster deployment of infrastructure changes.
What are the anti-patterns of DevOps?
Patterns are common practices that are usually followed by organizations. An anti-pattern is formed when an organization continues to blindly follow a pattern adopted by others but does not work for them. Some of the myths about DevOps include:
Cannot perform DevOps → Have the wrong people
DevOps ⇒ Production Management is done by developers
The solution to all the organization’s problems ⇒ DevOps
DevOps == Process
DevOps == Agile
Cannot perform DevOps → Organization is unique
A separate group needs to be made for DevOps
What are the benefits of using version control?
Here are the benefits of using Version Control:
All team members are free to work on any file at any time with the Version Control System (VCS). Later on, VCS will allow the team to integrate all of the modifications into a single version.
The VCS asks to provide a brief summary of what was changed every time we save a new version of the project. We also get to examine exactly what was modified in the content of the file. As a result, we will be able to see who made what changes to the project.
Inside the VCS, all the previous variants and versions are properly stored. We will be able to request any version at any moment, and we will be able to retrieve a snapshot of the entire project at our fingertips.
A VCS that is distributed, such as Git, lets all the team members retrieve a complete history of the project. This allows developers or other stakeholders to use the local Git repositories of any of the teammates even if the main server goes down at any point in time.