Chef DevOps Interview Questions

So, are you preparing for Chef DevOps interviews and looking for frequently asked Chef DevOps interview questions? Well, you have landed at the right place. It can be overwhelming to find many Chef DevOps interview questions online but going through all of them can be very time-consuming. In this blog, I will talk about the popular 20 Chef DevOps interview questions that you must know in order to crack your Chef  DevOps interviews with ease. We will be looking at the interview questions which a typical Chef DevOps engineer faces in an interview. This is both for people who are new to the DevOps world and people who are experienced in other fields like Linux or production support and are willing or wanting to move to DevOps. So, let us get started!

Q1. What is Chef?

Chef is an open-source, powerful automation, and configuration management tool. Opscode created the chef configuration management tool, that provides a way to transforms infrastructure into code. It is used to automate infrastructure provisioning. It is developed based on Ruby DSL language. The major components of chef are:

• Chef Server: It is the central store of your infrastructure configuration data. The chef server stores the data which is needed to configure your nodes and provide search, that is a powerful tool which allows you to drive node configuration based on data dynamically
• Chef Node: A Chef node is a host that is configured using chef client. The Chef client runs on your nodes, they contact the chef server for the information necessary to configure the node. Since a node is a commodity hardware that runs the chef client software, they are sometimes referred to as clients.
• Chef Workstation: A chef workstation is a host which you can use to modify the chef cookbooks and other configuration data. All the configurations are forwarded to the Chef server after they are tested in the chef workstation.

Q2. What are the main benefits of Chef?

Chef is a configuration management tool which is used for automation with infrastructure as code. It has multiple benefits, and below are some of those:

• Cloud deployment, you can use Chef to perform automated deployment in the cloud environments.
• Multi-cloud support in Chef allows we can even use multiple cloud providers for our infrastructure.
• Hybrid deployment in Chef supports both cloud-based as well as data center based infrastructure.
• High availability with chef automation can create a high availability environment. Chef can maintain or start new servers in an automated way to maintain a highly available environment in case of hardware failure.

Q3. What a Chef DK?

The chef DK workstation is the location using which users interact with Chef. On the workstation, users create and test cookbooks using chef tools such as Test Kitchen and interact with the Chef server using knife and chef command-line tools.

Q4. What is the architecture of Chef?

Chef architecture is composed of multiple components like chef server, chef client, etc. Some of the main components in chef are as follows:

• Client: These are the individual users or the nodes which communicate with chef server.
• Chef Manage: It is the web console that is used or interacting with the Chef server.
• Load balancer: All the chef server API requests are routed through the load balancer, and it is implemented using Nginx.
• Bookshelf: It is the chef component that stores cookbooks. All these cookbooks are stored in a repository which is separate storage from the chef server.
• PostgreSQL: It acts as the data repository for chef server.
• Chef server: It is the hub for all the configuration data. It also stores all the cookbooks and policies. It can scale to any size, which can be of enterprise level.

Q5. What is a resource in Chef?

A resource in Chef tool represents a piece of infrastructure in its desired state, such as a service that should be running, a package that should be installed, or a file that should be generated.

Q6. What is a recipe in Chef?

A recipe in Chef tool is a collection of several resources that describes a particular policy or a  configuration. With the help of Chef recipe, you can describe everything that is needed to configure a system.

Q7. What is a node in Chef?

A node in Chef represents a server and is typically a virtual machine containing your physical server or instance, basically any computer resource in your infrastructure that is Chef manages.

Q8. What is the role of the starter kit in Chef?

The starter kit in Chef will create some important configuration files like chef directory, the ORGANIZATION-validator.pem, knife.rb, and USER.pem files, etc., with the correct information that is required to interact with the chef server.

Q9. What are the products offered by Chef for DevOps operations?

Products offered by Chef include:

• Chef Enterprise Automation Stack
  • Chef Infra
  • Chef InSpec
  • Chef Habitat
  • Chef Automate
• Chef Infrastructure Management
• Chef Compliance
• Chef App Delivery
• Chef Desktop

Q10. Can you explain knife in chef?

In Chef, knife is a command-line tool which provides an interface between a local chef repo and the chef server. This tool helps users to manage:

• cookbooks and recipes
• resources within various cloud environments
• nodes
• roles, environments, and data bags
• the installation of the chef client onto nodes
• searching of indexed data on the chef server

Q11. Define Chef resource and state its functions.

Chef resource is a component of the infrastructure which is essential for installation and running a service. Below are the different functions of Chef resources:

• Provides the description of the desired state of the configuration item.
• It can select different resources such as template, services, package, etc.
• Documents about all the resource properties and other crucial details.
• Shares insights on the steps involved in achieving a specific state for a particular item.
• The combination of different resources into recipes describes the working configuration.

Q12. How does a cookbook differ from a recipe in Chef?

Recipe is a group of resources in Chef. It primarily configures some piece of infrastructure or a software package, whereas a cookbook groups together multiple recipes and other information in a way that can be more manageable than having just recipes alone.

Q13. What is run-list in Chef?

run-list is used 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.

A run-list is:

• An ordered list of recipes and/or roles that run in the same order defined in the run-list. The chef-client will not run a recipe twice if the recipe appears more than once in the run-list.
• A knife tool is used to maintain it.
• run-list is uploaded from the workstation to the Chef server or is maintained using the Chef management console.
• 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.
• run-list is stored on the node object on the Chef server.

Q14. What is Chef Infra?

Chef infra is a powerful automation platform that transforms infrastructure into code. Whether you are operating in the cloud, on-premises or a hybrid environment, chef infra automates how infrastructure is configured, deployed and managed across your network no matter its size.

Q15. Why do you have SSL certificates used for Chef?

Fundamentally your immediate answer should be security SSL provides for a very high level of private security and private and public key pairing. This really is essential to ensure that you have a secure environment throughout your entire network. The second part should be that if you are using SSL and you are using the private public key model within SSL, then you are able to guarantee the system is on your network. You will be able to validate that the nodes within your network that Chef is validating against are the actual nodes themselves, not imposters.

Q16. What is Test Kitchen?

Test Kitchen is essentially a command-line tool that allows you to be able to test out your cookbook before you actually deploy it to an actual node. Some of the commands that you would use are for instance, if you want to create an instance of Test Kitchen, you will do kitchen create, if you are going to destroy an instance after you created it, you do kitchen destroy. If you want to be able to combine multiple instances, you will do kitchen converge, if you want to setup instances, then you use kitchen setup, if you wish to verify instances, then you use kitchen verify.

Q17. How does chef apply differ from chef client?

So fundamentally, the difference between them is that chef apply will validate the recipe that you are working on, whereas chef client looks to apply and validate the entire cookbook that runs in your server environment. So one is focused on the recipe, and the other is focused on the entire cookbook.

Q18. Can you explain Chef Jenkins plugin?

Chef Jenkins plugin adds the ability to use Jenkins for continuous integration and continuous deployment and synchronization of environments from a git repository in Chef.

Q19. Can you explain chef-trac-hacks in chef?

In Chef, chef-trac-hacks is used to add the ability to fill a coordination gap between Amazon Web Services (AWS) and the chef client.

Q20. Tell us about the differences between Chef and Puppet?

Both Chef and Puppet are configuration management DevOps tools for cloud-based and on-premises infrastructure. Both the tools require familiarity in the Ruby language. The differences between the two are enlisted in the below table:

Final Thoughts

Chef is an important DevOps tool, and there is plenty to learn. Do not just mug up these answers, understand the technicalities of these answers also. You can find thousands of Chef DevOps interview questions online, but these are the top 20 Chef DevOps interview questions which you must know, and these are the questions that will give you a kickstart to your future Chef DevOps interviews. So, prepare well and all the best!