DevOps is increasingly becoming a popular way to build and deploy applications which has translated into increasing demand for DevOps professionals.
This article will cover some of the most frequently asked DevOps interview questions and their answers. Using these questions as core to study can increase your chances of getting hired, or if you are a recruiter, they can help you in the hiring process.
Frequently Asked DevOps Interview Questions and Answers
What is DevOps for you?
DevOps is an approach aimed at improving work throughout the software development lifecycle. The DevOps process is depicted as an infinite loop, comprising the stages of planning, coding, building, testing, releasing, deploying, operating, and monitoring.
DevOps influences the application lifecycle throughout its planning, development, delivery, and operation phases. Each phase depends on the others, and the phases are not specific to a role. In a true DevOps culture, each role is involved in each phase to some degree.
Why is DevOps important?
Teams that take a DevOps approach tend to get their projects done faster. This way, communication errors are avoided, facilitating the rapid implementation of improvements and other necessary changes. The DevOps approach encourages greater collaboration between the development and operations teams, where the goals of all of them are more aligned. You can summarize some of the benefits as follows:
- Improved communication
- Teamwork and cohesion
- Improved collaboration
- Faster delivery of quality products
- Reduced complexity and quick problem resolution
- Greater scalability and flexibility to add new code
- More stable operating environments
- Greater automation
- Cost reduction and resource utilization
- Security through integrated and automated tools
What are the daily tasks of DevOps?
Some of the daily tasks you could mention are:
- Ensure continuous integration and deployment
- Assign and communicate tasks to be performed
- Design and order test protocols
- Monitoring and collection of infrastructure and application metrics
- Analysis of results obtained in each phase of development
- Reduce error rate and recovery time in case of errors
- Reduce delivery time
How does DevOps help developers?
When a DevOps methodology is implemented, developers no longer have to wait for feedback from the operations team to fix bugs within their code. But now, they can solve these problems faster because they have continuous feedback on their code.
What is version control?
Version control is a practice that allows us to keep track of the changes we make to a file or set of files over time so that specific versions can be retrieved later. A version control tool allows us to easily track the progress of your development work and save different versions of source code to return to the previous one as and when needed. One of the most used tools at this stage of software development is Git.
What is CI/CD, and what are its benefits?
Continuous integration (CI)
CI combines tools and practices that make it easy to deliver high-quality, rapid software. This way, bottlenecks are eliminated, and technical problems are avoided in the launch phases.
Continuous Delivery (CD)
This practice automates the delivery of code changes, ensuring that the code can be quickly supplemented in production and that applications function correctly.
Continuous Deployment (CD)
Unlike continuous delivery, the objective of this practice is that there is no human intervention when deploying the software in production. Publishing new or changed code to production is automated.
CI/CD implements DevOps throughout the application lifecycle. These practices help improve productivity in the different phases of the software development process by streamlining and automating them.
What is Continous Monitoring
Continuous monitoring is a DevOps practice that involves monitoring, alerting, and taking action on both code and infrastructure. So that problem that may arise in the implementation is quickly detected and identified, reducing the time in resolving problems.
Why is continuous testing important?
Continuous testing is automating tests early, gradually, and appropriately in the development pipeline. It is essential because it allows ensuring the quality of the code. Errors are detected early, and code feedback is done faster.
Explain a few types of tests used in DevOps?
They test a specific piece of code in isolation. Unit tests must not be connected to the database, use the file system, talk to external systems, or interact with system components. It allows them to run quickly, and you get quick feedback if changes have broken existing functionality.
They test large groups of features so that they can identify problems like these. They are generally slower, requiring more complex configuration and more I/O connecting to a database, file system, or other systems.
Such tests verify that the deployment worked, in other words, that your application is correctly installed, configured, can access whatever services it needs, and is responding.
Apart from these, there are also exploitation and useability tests. To know more about testing, check the article on types of application testing.
What is microservices architecture, and how is it different from traditional architecture?
The traditional method of writing software is monolithic. It means that all the functions of an application are gathered in a single block. In case of errors or need to update, the code that governs the entire product is analyzed.
It generates stops or even crashes and represents a great danger to the conservation of the code. For customers, it means losses and headaches.
In a microservices architecture, an application’s functions represent an independently developed and integrated service. The components are separate but work together to perform the correlated tasks.
In this way, each independent service runs without interfering with the others, which also applies in failure cases. If a function fails, it is possible to adjust it without compromising the functioning of the entire application.
Microservices arrive to make DevOps even more agile and efficient, accelerating end-to-end development and making applications even more scalable.
What is Infrastructure as code?
Infrastructure as code is the approach to defining the computing and network infrastructure, which uses source code management techniques and is treated like any software system.
This code may be kept in source control to allow for audibility and reproducible construction, subject to testing practices and the full discipline of Continuous Delivery.
Infrastructure as code is based on a few practices:
- Use definition files
- Self-documented systems and processes
- Version all elements
- Continuously test systems and processes
- Small changes instead of batches
- Keep services available continuously
Build automation tools specify how the software should be built (what steps need to be done and in what order) and what dependencies are required (what other software needs to be present for the build to be successful).
Some tools are better suited for projects in specific programming languages, such as Maven and Apache’s Ant, which, while technology can be used with other languages, are mostly used in Java projects. Others, like Hudson or Jenkins, can be used more widely with various projects.
What is a DevOps Pipeline?
The DevOps pipeline is a process that encompasses several steps before releasing new software. It can be applied in all phases of the project, from integration and testing to delivery and deployment. In general, it goes through the following stages and teams:
- Product Vision: defines the features of the product;
- Dev Team: develops iteratively and incrementally;
- Area of operation: implements and maintains stable environments;
- Monitoring and feedback: seek to generate value and use by the customer.
What are the different stages of a CI/CD pipeline?
The steps that make up a CI/CD pipeline are a few grouped tasks called the pipeline stage. Briefly, they are:
- Compilation: stage in which the application is compiled;
- Test: the stage where the code is tested. Here, automation saves time and effort;
- Launch: when the application is sent to the repository;
- Deployment: The code is deployed to the production environment;
- Validation and Compliance: You can use image security verification tools like Clair to ensure the quality of your images by comparing them to known vulnerabilities (CVEs).
These are the most common stages of the DevOps pipeline. However, each company has its specific needs and pipeline.
What does platform virtualization mean, and what are its benefits?
Platform virtualization means simulating an entire computer system to run multiple instances of operating systems simultaneously on a single physical machine.
In this configuration, a virtual machine monitor (VMM), or hypervisor, has full control of the physical machine’s hardware resources. Guest operating systems run in virtual machines, which VMM manages. Environment virtualization involves simulating one or more virtual machines and the network connections between them.
Virtualization can help reduce the time spent on deployment and the risks associated with it in several ways. The use of virtual machines in deployment is a huge help in achieving effective configuration management vertically and horizontally across your systems.
In particular, the use of virtualization brings the following benefits:
- Quick response to changing requirements
- Ease of maintenance of baselines
What is the difference between containers and virtual machines?
Both the Container and the VM work with virtualization and isolation of environments to promote processing independently of applications. Still, Containers create isolated environments where different applications can run simultaneously because the division is made at the level of available resources, such as memory and processing. On the other hand, the Virtual Machine allows a physical machine to house others with different operating systems, hard disks, and hardware-independent from the original ones.
What is the main difference between Docker and Kubernetes?
Docker is one of the most used DevOps container tools. It focuses on the portability of applications, placing them in technological containers and packaging systems and moving them across different platforms.
At the same time, Kubernetes is a container orchestration tool that can group containers by logical categorization. It can be deployed to multiple computers through automated distribution.
Read more about Kubernetes Vs. Docker.
What are some Telemetry metrics in DevOps?
- Business level: Examples include the number of sales transactions, revenue from sales transactions, user sign-ups, churn rate, and A/B test results.
- Application-level: Examples include transaction times, user response times, and application failures.
- Infrastructure level: Examples include web server traffic, CPU load, and disk usage.
- Client software level: Examples include application errors, crashes, and user-measured transaction times.
- Deployment Pipeline level: Examples include build pipeline status (red or green for various automated test suites), changing deployment deadlines, deployment frequencies, test environment promotions, and environment status.
What technologies do you use to do DevOps?
This question aims to know what technologies you can use to implement the DevOps culture within the organization. Some of the most common technologies that a DevOps can use are:
- Continuous development: Git, SVN, Mercurial, CVS, Jira
- Continuous integration: Jenkins, Bamboo, Hudson
- Continuous development: Nexus, Archive, Tomcat
- Continuous deployment: Puppet, Chef, Docker
- Continuous monitoring: Splunk, ELK Stack, Continuous Nagios
- Testing: Selenium, Katalon Studio
Tell us about your experience managing DevOps projects
DevOps skills are not just about technical know-how and require human and managerial skills often found among managers, program directors, and project managers.
It is essential to know how to manage and support change, provide a gateway to facilitate the transfer of new versions of code to the operations side, evaluate and monitor the various platforms and tools to measure performance, and analyze and share results to improve future deliveries, etc.
Approach this question with methodology and explain your journey in solving complex problems. How do you intend to go about improving the functioning of the infrastructures? How do you plan to collaborate with front, middle and back-office developers? What monitoring tools do you master? Also, consider sharing your conflict resolution experiences within your team.
To learn more, you may consider enrolling in one of these DevOps courses.