DevOps Interview Questions and Answers Pdf

1. Which among Puppet, Chef, SaltStack, and Ansible is the best Configuration Management (CM) tool? Why?
Answer:
This depends on the organization’s need to mention a few points on all those tools: Puppet is the oldest and most mature CM tool. Puppet is a Ruby-based Configuration Management tool, but while it has some free features, much of what makes Puppet great is only available in the paid version. Organizations that don’t need a lot of extras will find Puppet useful, but those needing more customization will probably need to upgrade to the paid version.
The chef is written in Ruby, so it can be customized by those who know the language. It also includes free features, plus it can be upgraded from open source to enterprise-level if necessary. On top of that, it’s a very flexible product. (devops interview questions and answers pdf)

Ansible is a very secure option since it uses Secure Shell. It’s a simple tool to use, but it does offer several other services in addition to configuration management. It’s very easy to learn, so it’s perfect for those who don’t have a dedicated IT staff but still need a configuration management tool.

SaltStack is a python based open-source CM tool made for larger businesses, but its learning curve is fairly low.

2. Explain Security management in terms of Cloud Computing?
Answer:

Identity management access provides the authorization of application services.
Access control permission is given to the users to have complete controlling access of another user who is entering into the cloud environment.
Authentication and Authorization provide access to only authorized and authenticated users only to access the data and applications.

3. What is an MX record?

Answer: An MX record tells senders how to send an email for your domain. When your domain is registered, it’s assigned several DNS records, which enable your domain to be located on the Internet. These include MX records, which direct the domain’s mail flow. Each MX record points to an email server that’s configured to process mail for that domain. There’s typically one record that points to a primary server, then additional records that point to one or more backup servers. For users to send and receive an email, their domain’s MX records must point to a server that can process their mail.

4. How do all these tools work together?
Answer:

Given below is a generic logical flow where everything gets automated for seamless delivery. However, this flow may vary from organization to organization as per the requirement.
Developers develop the code and this source code is managed by Version Control System tools like Git etc.
Developers send this code to the Git repository and any changes made in the code are committed to this Repository.
Jenkins pulls this code from the repository using the Git plugin and builds it using tools like Ant or Maven.
Configuration management tools like puppet deploys & provisions testing environment and then Jenkins releases this code on the test environment on which testing is done using tools like selenium.
Once the code is tested, Jenkins sends it for deployment on the production server (even production server is provisioned & maintained by tools like a puppet).
After deployment, It is continuously monitored by tools like Nagios.
Docker containers provide a testing environment to test the build features.

5. What is an AMI? How do we implement it?
Answer:

AMI stands for Amazon Machine Image. It is a copy of the root file system.
It provides the data required to launch an instance, which means a copy of running an AMI server in the cloud. It’s easy to launch an instance from many different AMIs.
Hardware servers that commodities bios which exactly point the master boot record of the first block on a disk.
A disk image is created which can easily fit anywhere physically on a disk. Where Linux can boot from an arbitrary location on the EBS storage network. (E Learning Portal)

6. What are Plugins in Nagios?
Answer: Begin this answer by defining Plugins. They are scripts (Perl scripts, Shell scripts, etc.) that can run from a command line to check the status of a host or service. Nagios uses the results from plugins to determine the current status of hosts and services on your network.

Once you have defined Plugins, explain why we need Plugins. Nagios will execute a plugin whenever there is a need to check the status of a host or service. The plugin will perform the check and then simply returns the result to Nagios. Nagios will process the results that it receives from the Plugin and take the necessary actions.

7. Why is Continuous monitoring necessary?
Answer:

I will suggest you go with the below mentioned flow:

Continuous Monitoring allows timely identification of problems or weaknesses and quick corrective action that helps reduce expenses of an organization. Continuous monitoring provides a solution that addresses three operational disciplines known as:

continuous audit
continuous controls monitoring
continuous transaction inspection

8. What Happens During The Bootstrap Process?
Answer: During the bootstrap process, the node downloads and installs the chef-client registers itself with the Chef server and does an initial check-in. During this check-in, the node applies any cookbooks that are part of its run-list.

9. Explain whether it is possible to share a single instance of a Memcache between multiple projects?
Answer: Yes, it is possible to share a single instance of Memcache between multiple projects. Memcache is a memory store space, and you can run Memcache on one or more servers. You can also configure your client to speak to a particular set of instances. So, you can run two different Memcache processes on the same host and yet they are completely independent. Unless, if you have partitioned your data, then it becomes necessary to know from which instance to get the data from or to put it into.

10. You are having multiple Memcache servers, in which one of the Memcache servers fails, and it has your data, will it ever try to get key data from that one failed server?
Answer: The data in the failed server won’t get removed, but there is a provision for auto-failure, which you can configure for multiple nodes. Fail-over can be triggered during any kind of socket or Memcached server level errors and not during normal client errors like adding an existing key, etc.