DevOps Interview Questions for Tech Companies in Singapore

DevOps works on the principle of collaboration between teams with a focus on faster delivery.  It can be understood as a culture among people of the development and operations teams which leverages the power of automation. 

DevOps touches every component of the software life cycle- development, testing, operations, security, and business. Big businesses and small enterprises everyone is embracing DevOps today and hence this becomes an important factor in a Tech-related career.  

We have divided the DevOps interview questions into the below sections:

1. Basic DevOps questions 
2. Version Control System
3. Continuous Integration and Continuous Deployment
4. Continuous Testing
5. Configuration Management
6. Configuration Monitoring

Basic DevOps interview questions:

What is DevOps?

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DevOps is a culture where planning, development, operations, testing, delivery, security teams collaborate to provide better and reliable products. 

The phases as listed below,are non-exclusive of each other. They all work in tandem. 

• Plan: DevOps team defines, describes, and tracks the features of the product. 
• Develop: Development of code and testing. 
• Deliver: The team deploys the product or application in the production environment. 
• Operate: Maintenance and monitoring of the application in the production environment. 

What are the differences between DevOps and Agile?

The below table depicts the differences between DevOps and Agile:

Explain the various components of DevOps.

Components or processes of DevOps are:

• Continuous Integration: CI involves the frequent merger of new code into the existing code. 
• Continuous Testing: CI is followed by automated Continuous Testing. CT is executed automatically as soon as the new code is committed by developers.
• Continuous Delivery: CD is the automatic deployment of code into the production environment.
• Continuous Monitoring: The application performance is monitored in real-time and in case of issues the team takes action quickly.

What are the advantages of DevOps? 

• Reliability: DevOps reduces the failure rate of new releases. 
• Adaptive: The changes can be accommodated quickly.
• Quick Delivery: DevOps provides reliable software faster due to the involvement of the whole team and not just developers.
• Quick Recovery: In the instance where a new deployment fails, the application is recovered fast.
• Stability: Infrastructure as a code(IaC) provides a stable application.
• Security: DevOps provides better risk-mitigation.

What are the popular tools in DevOps? 

• Jenkins: CI tool 
• Git: Version Control System(VCS) tool 
• Selenium: Continuous Testing(CT) tool 
• Chef, Puppet, Ansible: Configuration Management and Deployment tools 
• Nagios, Monit: Continuous Monitoring tools 
• Docker: Containerization tool 

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Version Control System 

What is the Version Control System in DevOps and its advantages? 

A Version Control System(VCS) stores, tracks, and helps in managing the different versions of the code or files. Also, it stores the data related to the changes made e.g., who made changes, when were the changes made, and what are the changes. Additionally, in case of any conflict or failure, the code can be reverted using the VCS. 

Advantages of Version Control System in DevOps are: 

• Parallel changes: Concurrent changes are accepted by VCS. All the changes can be merged to provide a final version. 
• Change history: Tracking the change history is very easy using VCS. 
• Reliability: Better reliability is provided by VCS during the failure of the centralised server. Since in a distributed VCS, we can copy the project version history and use the local repository. 
• Bug tracking: It is easier to track when a bug got introduced in code with the help of the Version Control System. 

Types of VCS tools:

• Centralised Version Control System: Uses a central repository(server) to store files. 
• Distributed Version Control System: Local repository has a clone of files from the central repository. 

What are the VCS tools that you have worked with? 

Top popular VCS tools are below:

• Git Apache Subversion(SVN) 
• Mercurial 
• Microsoft Azure 
• Perforce Helix Core 
• AWS CodeCommit 

What do you know about Git in DevOps? 

Git is an open-source distributed version control system(DVCS). Each workstation/ team member has its local repository cloned from the main repository. 

Features of Git in DevOps: 

• Open-source
• High-performance speed 
• Provides scalability as the number of users increases 
• Provides reliability in case of central repository crash 
• Secure data transfer via checksum 
• Simple architecture because the central server is used only when push/pull happens. 
• Distributed coding Compatible with SVN, SSH, FTP, HTTP, etc. 

What is Infrastructure as Code(IaC)? 

IaC means automating the process of infrastructure provisioning and thus it saves manual effort. It helps in automatically provisioning and managing the servers, networks, virtual machines, database connections, and storage, etc. 

Benefits of Infrastructure as Code: 

• Consistent: IaC provides the same required configuration every time because it uses code for deployment.
• Faster provision than manual provision. 
• Faster results: Since the infrastructure provision is quick, consistent, and risk-free therefore all the phases(development, testing, and operations) are provided with the required environments faster. This aids in achieving the final development quickly. 
• Reduced time of provisioning when compared with the manual process. 

CI/CD 

This section has DevOps interview questions related to Continuous Integration, its advantages, CI/CD pipeline, Continuous Deployment and Continuous Delivery, IaC, containers. 

What is DevOps CI? 

It is a process of automatically integrating code from different developers into one central repository. It is a continuous process repeated many times a day to maintain consistency. After CI, automated test runs are executed to catch the bugs as early as possible. 

What are the advantages of Continuous Integration? 

• Smaller code integrations are faster 
• Reduced integration problems 
• Early bug detection results in quicker resolution of defects
• Early bug resolution is economical in terms of money and time 
• Facilitates more time for feature development 
• Faster delivery due to fewer issues faced by teams 

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