DevOps Interview Questions and Answers

DevOps refers to the close association of development as well as operational tasks. It does not refer to a set of tools or any software framework rather it is a combination of specialized tools that help in the automation of the entire infrastructure. It also refers to the implementation of Agile methodology on development as well as operational upfronts.

The basic component which is required for the Puppet configuration management policy is known as Puppet Manifest. Each of the Puppet nodes or Agents has your configuration details in their native language provided in Puppet master. The details are provided based on how resources should be configured and their terms. It also declared the resources by defining the state which needs enforcement on any note. To develop complex Puppet modules, they are considered the major building blocks.

Version control system or VCS refers to software which is utilized by the developers to work simultaneously maintaining the history of their previous as well as current actions.

Some of the salient features of VCS are-

• It helps developers to work together.
• It does not permit overwriting on changes.
• Maintains a complete history of earlier provisions and complete changes.

There are basically two types of version control systems found which are-

• A central version control system, its example is Git, Bitbucket
• A distributed or decentralized version control system, its example is SVN.

Git is basically a source code management tool that can handle multiple projects with efficiency and perfection. It is utilized to store the repositories for remote servers.

DevOps is actively used in the organizations to maintain application delivery and close alignment of services considering the business objectives. There are several reasons to adopt the technology offered by DevOps, some of them are-

• It helps in faster innovations
• It also provides less developmental cycles
• It also reduces the deployment failures
• Improvisations in communication and collaboration
• It offers a stable operating environment
• Significant increase inefficiencies
• Cost reduction along with the infrastructure and IT headcount

The core operations in DevOps for infrastructure are as follows-

• Provisioning
• Configuration
• Orchestration
• Deployment

For application development, the core operations are as follows-

• Code building
• Code coverage
• Unit testing
• Packaging
• Deployment

The majorly used key performance indicators (KPIs) in DevOps are-

• Deployment frequency and failure
• Change lead time
• Change in volume
• Mean time to detection
• Mean time to recovery (MTTR)
• Meantime in between failures
• Change in failure rate
• Efficiency
• Pipeline adoption
• Performance

The most significant tools in DevOps are-

• Git- version control system tool
• Jenkins- continuous integration tool
• Docker- containerization tool
• Puppet- configuration management and deployment tool
• Ansible- configuration management and deployment tool
• Nagios- continuous monitoring tool

The key components in DevOps essentially involve-

• Continuous integration
• Continuous delivery
• Entire microservices
• Infrastructure as a code
• Monitoring and logging
• Communication and collaboration

The most recognizable adoption of DevOps seen in the industry involves the utilization of agile and various developmental processes and methodologies. It also involves the demand for an increase in production release from a business point of view. Its other adoptions involve-

• Large availability of cloud infrastructure for external as well as internal providers
• increase in data center configuration management tools
• Improvisation in automation
• Increased focus on test automation and continuous integration process
• Enhanced practices over critical issues

It is almost always asked in the DevOps interview questions.

Pair programming is an engineering practice of the well defined and extreme programming rules. In these, two different programmers work simultaneously on one computer, on the same design, algorithm, code or test. Where one programmer acts as an "observer" while others act as a "driver", it is their shared responsibility to monitor the errors. Without any handoff, their roles can be exchanged or shifted at any point in the process.

Its significant advantage is that it helps in raising the theory among different points of view which can eventually help to increase our understanding of the same concept considering the code, algorithm or design.

When it comes to DevOps continuous delivery and continuous integration are very important to consider and understand. Both of them are critical steps where continuous integration refers to an automated build-up that results as a generation. It is a software development practice in which members of the teams frequently line up and integrate their code which later undergoes the generation process. It is then verified carefully along with the code written by the members. Each of these integrations is then verified daily and tested as a significant part of the development process.

One of the core advantages of DevOps automation is that it manages the role of human error out of the CD equation.

Continuous monitoring is required when the application is developed and deployed in order to check for its performance. With its help, it is possible to find the loopholes or defects which might have been missed by the team earlier. Continuous testing is utilized to make the application out to reach the end-users. Without sufficient continuous testing or unit testing and automation, it is not possible to get the desired results. To validate the code and integrate them with developers it is essentially required.

Git refers to a distributed version control system that is used for recording the changes in source code during the time of development. It also monitors the set of project overtime and stores the required information in a structure called repository.

Some of the essential commands are-

• Git config- for global username
• Git init- for the repository name
• Git clone- for clone
• Git add- to add the file

The most common and popularly used deployment patterns are Blue-Green deployment and Canary release. In blue-green deployment, two different and identical environments are present where the green environment refers to the initial production system. Actual deployment takes place in the blue environment. It is also responsible to monitor for in error fault and once everything starts working fine then the load balancing and another component instantly switch the green environment to blue.

Canary releases have the efficiency to roll out any specific feature to a subset for a developer. This release helps the developer to reduce the risk factor involved in the release of new features.

Containers in DevOps refers to the operating systems' virtualizations. A single container can be utilized to run everything including from staging the environment into production. This also consists of the entire runtime environment for example libraries, necessary executables, configuration files, binary code and many more. Containers are streamlined in order to create, deploy, redeploy and test the applications in various environments.

There most prominent benefits are-

• Reduction in the overheads.
• Improve productivity.
• Consistency with operational tasks.
• Application development is also enhanced.
• Extreme efficiency.

It is a general question asked in DevOps interview questions.

Continuous monitoring helps the developer to detect and analyze the security implications to get a better view of planned or unplanned changes. Continuous monitoring also helps to assess the vulnerabilities for errors that are in a space of threat. To deliver the information based on application performance and the patterns of usage it works better.

Some of the best continuous monitoring tools are-

• Nagios
• Tenable
• Solarwinds
• Lansweeper
• Spiceworks
• Snorts

Chef resource defines a small segment of the operating system in its desired state. It also refers to a configuration policy statement that is utilized to represent the desired state of any node and then to the current configuration. All together it helps resource providers and developers.

The functions of a Chef Resource are-

• The present status of the target machine can be known for its help
• it also defines the steps which are required to perform to get the target machines
• It also specifies the resources for example templates, services, files or packages.