Chef Interview Questions and Answers

1. Why are SSL certificates Used in Chef?
Answer: You need the SSL certificate for the initial configuration of the Chef and for creating the certificate and private keys in Nginx. This ensures that the right data can be accessed between the Chef Client and Chef Server. (Chef Interview Questions and Answers)

2. What is VirtualBox? What is Vagrant?
Answer: Virtual Box is the software that manages your virtual machine instances.Vagrant helps Test Kitchen communicate with VirtualBox and configures things like available memory and network settings.

3. How would you explain the concept of “infrastructure as code” (IaC)?
It is a good idea to talk about IaC as a concept, which is sometimes referred to as a programmable infrastructure, where infrastructure is perceived in the same way as any other code. Describe how the traditional approach to managing infrastructure is taking a back seat and how manual configurations, obsolete tools, and custom scripts are becoming less reliable. Next, accentuate the benefits of IaC and how changes to IT infrastructure can be implemented in a faster, safer and easier manner using IaC. Include the other benefits of IaC like applying regular unit testing and integration testing to infrastructure configurations, and maintaining up-to-date infrastructure documentation.

If you have completed a certification on Amazon Web Services (AWS), and are interviewing for niche roles such as AWS-certified DevOps engineer, here are some.

4.  How is IaC implemented using AWS?
Answer: 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.

As a DevOps engineer, an in-depth knowledge of processes, tools, and relevant technology are essential. You must also have a holistic understanding of the products, services, and systems in place. If your answers matched the answers we’ve provided above, you’re in great shape for future DevOps interviews. Good luck! If you’re looking for answers to specific DevOps interview questions that aren’t addressed here, ask them in the comments below. (e Learning Portal)

5. How does a Chef Repository work?
You can think of the Chef Repository as a collection of Cookbooks, roles, environments, data bags and more. It is possible to sync the Chef Repository with the Git and a Version Control System in order to improve the performance of it. 

6. Give me an example of how you would handle projects?
 As a professional with managerial responsibilities, I would demonstrate a clear understanding of DevOps project management tactics and also work with teams to set objectives, streamline workflow, maintain scope, research and introduce new tools or frameworks, translate requirements into the workflow and follow up. I would resort to CI, release management and other tools to keep interdisciplinary projects on track.

7. How do you expect you would be required to multitask as a DevOps professional?

I believe I’ll be expected to:

1. Focus attention on bridging communication gaps between Development and Operations teams.
2. Understand system design from an architect’s perspective, software development from a developer’s perspective, operations and infrastructure from the perspective of a seasoned Systems Administrator.
3. Execute – to be able to actually do what needs to be done.

8. What’s a PTR in DNS?
Pointer records are used to map a network interface (IP) to a hostname. These are primarily used for reverse DNS. Reverse DNS is set up very similar to how normal (forward) DNS is setup. When you delegate the DNS forward, the owner of the domain tells the registrar to let your domain use specific name servers.

9. Tell us about the CI tools that you are familiar with?
 The premise of CI is to get feedback as early as possible because the earlier you get feedback, the fewer things cost to fix. Popular open-source tools include Hudson, Jenkins, Cruise Control and Cruise Control.NET. Commercial tools include Thought Works’ Go, Urbancode’s Anthill Pro, Jetbrains’ Team City, and Microsoft’s Team Foundation Server.

10. How much have you interacted with cloud-based software development?
Share your knowledge around the use of cloud platforms, provisioning new instances, coding new software iterations with the cloud provider’s APIs or software development kits, configuring clusters to scale computing capacity, managing workload lifecycles and so on. This is the perfect opportunity to discuss container-based cloud instances as an alternative to conventional VMs. Event-based cloud computing, such as AWS Lambda offers another approach to software development, a boon for experienced DevOps candidates. In your interview, mention experience handling big data, which uses highly scalable cloud infrastructures to tackle complex computing tasks. 

11. What is exception handler in chef?
An exception handler is used to identify situations that have caused a chef-client run to fail. An exception handler can be loaded at the start of a chef-client run by adding a recipe that contains the chef_handler resource to a node’s run-list. Does an exception handler run when the failed? property for the run_status object returns true.

12. What is Handler DSL in chef?
Answer: Use the Handler DSL to attach a callback to an event. If the event occurs during the chef-client run, the associated callback is executed. For example:

  • Sending an email if a chef-client run fails
  • Sending a notification to chat application if an audit run fails
  • Aggregating statistics about resources updated during a chef-client runs to StatsD

13. What are the different Knife plugins for cloud hosting platforms?
Answer: There are different knife plugins available for cloud hosting platforms:
knife azure, knife blue box, knife ec2, knife eucalyptus, knife google, knife Linode, knife open stack, and knife Rackspace

14. How does a Cookbook differ from a Recipe in Chef?
Answer: The answer to this is pretty direct My suggestion is to simply tell:

A Recipe is a collection of Resources, and primarily configures a software package or some piece of infrastructure. A Cookbook groups together Recipes and other information in a way that is more manageable than having just Recipes alone. 

15. Where can you get reusable cookbooks that are written and maintained by the Chef community?
Answer: You can directly answer this question by saying reusable Cookbooks are present at Chef Supermarket,

16. What is a report handler in chef?
a report handler is used when a chef-client run succeeds and reports back on certain details about that chef-client run. A report handler can be loaded at the start of a chef-client run by adding a recipe that contains the chef_handler resource to a node’s run-list. A report handler runs when success? property for the run_status object returns true.

17. How Does Chef-apply Differ From Chef-client?
Chef-apply applies a single recipe; chef-client applies a cookbook.

For learning purposes, we had you start off with chef-apply because it helps you understand the basics quickly. In practice, chef-apply is useful when you want to quickly test something out. But for production purposes. 

18. What Would You Set Your Cookbook’s Version To Once It’s Ready To Use In Production?
 According to Semantic Versioning, you should set your cookbook’s version number to 1.0.0 at the point it’s ready to use in production.

19. How would you make software deployable?
The ability to script the installation and reconfiguration of software systems is essential towards controlled and automated change. Although there is an increasing trend for new software to enable this, older systems and products suffer from the assumption that changes would be infrequent and minor, and so make automated changes difficult. As a professional who appreciates the need to expose configuration and settings in a manner accessible to automation, I will work with concepts like Inversion of Control (IoC) and Dependency Injection, scripted installation, test harnesses, separation of concerns, command-line tools, and infrastructure as code.

20. Which scripting languages do you think are most important for a DevOps engineer?
As far as scripting languages go, the simpler the better. In fact, the language itself isn’t as important as understanding design patterns and development paradigms such as procedural, object-oriented, or functional programming.

21. Describe two-factor authentication?
Two-factor authentication is a security process in which the user provides two means of identification from separate categories of credentials; one is typically a physical token, such as a card, and the other is typically something memorized, such as a security code. 

22. What is an MX record in DNS?
Answer: MX records are mail exchange records used for determining the priority of email servers for a domain. The lowest priority email server is the first destination for email. If the lowest priority email server is unavailable, mail will be sent to the higher priority email servers.

23. What other tools are you familiar with that might help you in this role?
DevOps is so diverse and inclusive that it rarely ends with coding, testing, and systems. A DevOps project might rely on database platforms like SQL or NoSQL, data structure servers like Redis, or configuration and management issue tracking systems like Redmine. Web applications are popular for modern enterprises, making a background with Web servers, like Microsoft Internet Information Services, Apache Tomcat or other Web servers, beneficial. Make sure to bring across that you are familiar with Agile application lifecycle management techniques and tools.

24. What special training or education did it require for you to become a DevOps engineer?
Tips to answer: DevOps is more of a mindset or philosophy rather than a skill-set. The typical technical skills associated with DevOps Engineers today is Linux systems administration, scripting, and experience with one of the many continuous integration or configuration management tools like Jenkins and Chef. What it all boils down to is that whatever skill-sets you have, while important, are not as important as having the ability to learn new skills quickly to meet the needs. It’s all about pattern recognition and having the ability to merge your experiences with current requirements. Proficiency in Windows and Linux systems administration, script development, an understanding of structured programming and object-oriented design, and experience creating and consuming RESTful APIs would take one a long way.

25. What is the difference between a Cookbook and a Recipe in Chef?
When you group resources together what you get is a Recipe and this is useful in executing the configurations and policy. When you combine Recipes what you get is a Cookbook and this is easily manageable as compared to a Recipe.

26. What is the importance of Chef starter kit?
The starter kit is needed for creating the configuration files in Chef. It gives you the information for interacting with the server and defining the configuration file. You can easily download the starter kit and use it at the desired place on the workstation.

27. What information do you need to in order to bootstrap?

Answer: You need:

  • your node’s hostname or public IP address.
  • a user name and password you can log on to your node with.
  • Alternatively, you can use key-based authentication instead of providing a user name and password.

28. How would you ensure traceability?
This question probes your attitude to metrics, logging, transaction journeys, and reporting. You should be able to identify that metric, monitoring and logging need to be a core part of the software system, and that without them, the software is essentially not going to be able to appear maintained and diagnosed. Include words like Syslog, Splunk, error tracking, Nagios, SCOM, Avicode in your answer.

29. Are you more Dev or Ops?
This is probably the trickiest question that you might face in the interview. Emphasize the fact that this depends a lot on the job, the company you are working for and the skills of people involved. You really have to be able to alternate between both sides of the fence at any given time. Talk about your experience and demonstrate how you are agile with both.

30. What is a Chef resource and what are its functions?
You can think of the Chef resource as a part of the infrastructure which is used for installing or running a service. Here we will discuss some of the important Chef resources:

The desired state of a configuration item can be described

To bring a certain item to a state you will know what are the steps involved

You can choose the resources like package, template or services

You can list the resource properties and other details needed

You can group the resources into recipes for describing the working configuration.

31. What is a Chef Node and what is its importance?
We can think of the node as a physical server or a virtual machine that is a constituent of the Chef architecture. You can execute any resource with Chef. 

32. What is the significance of a Signed Header?
The Signed Header is needed for the validation of the interaction between the Chef node, server and signed header authentication.

33. What is the difference between an Asset and a Configuration Item?
According to me, you should first explain Asset. It has a financial value along with a depreciation rate attached to it. IT assets are just a sub-set of it. Anything and everything that has a cost and the organization uses it for its asset value calculation and related benefits in tax calculation fall under Asset Management, and such item is called an asset.

Configuration Item, on the other hand, may or may not have financial values assigned to it. It will not have any depreciation linked to it. Thus, its life would not be dependent on its financial value but will depend on the time until that item becomes obsolete for the organization.

Now you can give an example that can showcase the similarity and differences between both:
1) Similarity:
Server – It is both an asset as well as a CI.
2) Difference:
Building – It is an asset but not a CI.
Document – It is a CI but not an asset

34. What is chef-deploy plugin in chef and what is the purpose of using it?
Chef-deploy adds a gem that contains resources and providers for deploying Ruby web applications from recipes.

35. Write A Service Resource That Stops And Then Disables The Httpd Service From Starting When The System Boots?

Service ‘httpd’ do
Action [: stop: disable]

36. What is run-list in Chef?

  • Run-list lets you specify which Recipes to run, and the order in which to run them. The run-list is important when you have multiple Cookbooks and the order in which they run matters.
  • Depending on the discussion if you think more explanation is required just mention the below points
  • A run-list is:
  • An ordered list of roles and/or recipes that are run in the exact order defined in the run-list; if a recipe appears more than once in the run-list, the chef-client will not run it twice.
  • Always specific to the node on which it runs; nodes may have a run-list that is identical to the run-list used by other nodes.
  • Stored as part of the node object on the Chef server.
  • Maintained using a knife, and then uploaded from the workstation to the Chef server, or is maintained using the Chef management console.

37. Give me an example of how you would handle projects?
Answer: As a professional with managerial responsibilities, I would demonstrate a clear understanding of DevOps project management tactics and also work with teams to set objectives, streamline workflow, maintain scope, research and introduce new tools or frameworks, translate requirements into the workflow and follow up. I would resort to CI, release management and other tools to keep interdisciplinary projects on track.

38. What are the advantages of NoSQL database over RDBMS?

The advantages are:

1. Less need for ETL
2. Support for unstructured text
3. Ability to handle change over time
4. Breadth of functionality
5. Ability to scale horizontally
6. Support for multiple data structures
7. Choice of vendors

39. Why do we use the cloud-chef plugin in chef?
Jclouds-chef plugin adds Java and Clojure components to the Chef server API REST API.

40. What is a Recipe in Chef?
 Here also I will suggest you use the above-mentioned flow, first define Recipe.

A Recipe is a collection of Resources that describes a particular configuration or policy. A Recipe describes everything that is required to configure part of a system.

Now after the definition I will explain the functions of Recipes by including the following points:

  • Install and configure software components.
  • Manage files.
  • Deploy applications.
  • Execute other Recipes.EC

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