Ansible Interview Questions

Interview Questions On Ansible

We’ve compiled a series on Ansible, titled ‘Preparation for the Deployment of your IT Infrastructure with Ansible IT Automation Tool‘, through parts 1-4 and covers the following topics.

Q1. What is Ansible?

Ans: Ansible is a software tool to deploy an application using ssh without any downtime. It is also used to manage and configure software applications. Python language develops Ansible.

Q2. What are the Advantages of Ansible?

Ans:

1. Agentless
2. Very low overhead
3. Good performance

Q3. How Ansible Works?

Ans:

• There are many similar automation tools available like Puppet, Capistrano, Chef, Salt, Space Walk, etc, but Ansible categorizes into two types of servers: controlling machines and nodes.
• The controlling machine, where Ansible is installed, and Nodes are managed by this controlling machine over SSH(Secure Shell). By controlling the machine through inventory, the location of nodes is specified.
• Using SSH protocol, the controlling machine (Ansible) deploys modules to nodes and these modules are stored temporarily on remote nodes through a JSON connection, they will communicate with the Ansible machine over the standard output.

• There is no need for any agent installation on remote nodes because Ansible is agent-less, so it means there are no background daemons or programs executing for Ansible when it’s not managing any nodes.
• Ansible can handle 100’s of nodes from a single system over an SSH connection and the entire operation can be handled and executed by one single command ‘ansible’. But, in some cases, where you are required to execute multiple commands for a deployment, here we can build playbooks.
• Playbooks are a bunch of commands which can perform multiple tasks, and each playbook is in YAML file format.

Q4. What’s the Use of Ansible?

Ans: Ansible can be used in IT infrastructure to manage and deploy software applications to remote nodes. For example, let’s say you need to deploy a single software or multiple software to 100’s of nodes by a single command, here ansible comes into the picture, with the help of Ansible you can deploy as many as applications to many nodes with one single command, but you must have a little programming knowledge for understanding the ansible scripts.

Q5. Is there a web interface / REST API / etc?

Ans: Yes, Ansible, Inc makes a great product that makes Ansible even more powerful and easy to use. See Ansible Tower.

Q6. How do I submit a change to the documentation?

Ans: Documentation for Ansible is kept in the main project git repository, and complete instructions for contributing can be found in the docs.

Q7. When should I use {{ }}? Also, how to interpolate variables or dynamic variable names

Ans:

1. A steadfast rule is ‘always use {{ }} except when:‘. Conditionals are always run through Jinja2 as to resolve the expression, so when: failed_when: and changed_when: are always templates and you should avoid adding {{}}.
2. In most other cases you should always use the brackets, even if previously you could use variables without specifying (like with_ clauses), as this made it hard to distinguish between an undefined variable and a string.
3. Another rule is ‘moustaches don’t stack’. We often see this:
4. {{ somevar_{{other_var}} }}
5. The above DOES NOT WORK, if you need to use a dynamic variable use the hostvars or vars dictionary as appropriate:
6. {{ hostvars[inventory_hostname]['somevar_' + other_var] }}

Q8. How to install Ansible

Ans:

Installation of Ansible Ubuntu 14.04

The best way to get Ansible for Ubuntu is to add the project's PPA (personal package archive) to your system.

To do this effectively, we need to install the software-properties-common package, which will give us the ability to work with PPAs easily. (This package was called python-software-properties on older versions of Ubuntu.)

sudo apt-get update
sudo apt-get install software-properties-common

Once the package is installed, we can add the Ansible PPA by typing the following command:

sudo apt-add-repository ppa:ansible/ansible

 For the PPA addition, press enter.

After that we can refresh our system package, we can see available PPA packages and can install the software.

sudo apt-get install ansible sudo apt-get update Through Ansible, we have the software required to administer our servers.

Q9. How do I generate crypted passwords for the user module?

Ans: The mkpasswd utility that is available on most Linux systems is a great option:

mkpasswd --method=sha-512

If this utility is not installed on your system (e.g. you are using OS X) then you can still easily generate these passwords using Python.

First, ensure that the Passlib password hashing library is installed.

pip install passlib

Once the library is ready, SHA512 password values can then be generated as follows:

python -c "from passlib.hash import sha512_crypt; import getpass; print sha512_crypt.encrypt(getpass.getpass())"

Use the integrated Hashing filters to generate a hashed version of a password.

You shouldn’t put plaintext passwords in your playbook or host_vars; instead, use Vault to encrypt sensitive data.

Q10. By enabling Kerberized SSH, How do I get ansible to reuse connections?

Ans:

1. Use ‘-c ssh or ssh’ to Switch your default connection type in the configuration file, instead of Python use Native Open SSH for connections. paramiko library. In Ansible 1.2.1 and later, ‘ssh’ will be used by default if Open SSH is new enough to support Control Persist as an option.
2. Paramiko is great for starting out, but the OpenSSH type offers many advanced options. You will want to run Ansible from a machine new enough to support ControlPersist if you are using this connection type. You can still manage older clients. If you are using RHEL 6, CentOS 6, SLES 10 or SLES 11, the version of OpenSSH, is still a bit old, so consider managing from a Fedora or openSUSE client even though you are managing older nodes, or just use paramiko.
3. We keep paramiko as the default as if you are first installing Ansible on an EL box, it offers a better experience for new users.

Q11. What is the best way to make content reusable/redistributable?

Ans: If you have not done so already, read all about “Roles” in the playbook documentation. This helps you make playbook content self-contained and works well with things like git submodules for sharing content with others.

If some of these plugin types look strange to you, see the API documentation for more details about ways Ansible can be extended.

Q12. How do I see all the inventory vars defined for my host?

Ans: You can see the resulting vars you define in inventory by running the following command:

ansible -m debug -a "var=hostvars['hostname']" localhost

Q13. How do I copy files recursively onto a target host?

Ans: The “copy” module has a recursive parameter, though if you want to do something more efficient for many files, look at the “synchronize” module instead, which wraps rsync. See the module index for info on both modules.

Q14. What is Ansible Role?

Ans: Ansible can interact with configured clients from the command line with the ansible command, and how you can automate configuration with playbooks run through the ansible-playbook command.

The first step in creating a role is creating its directory structure. To create the base directory structure, we’re going to use a tool bundled with Ansible called ansible-galaxy:

$ ansible-galaxy init azavea.packer
azavea.packer was created successfully

That command will create an azavea.packer directory with the following structure:

├── README.md
├── defaults
│ └── main.yml
├── files
├── handlers
│ └── main.yml
├── meta
│ └── main.yml
├── tasks
│ └── main.yml
├── templates
└── vars
└── main.yml

Q15. Difference between the Variable name and Environment Variables.

Ans:

Q16.Mention the best ways to make content redistributable/reusable.

Ans: Ansible playbook’s files can be reused in three distinct ways: including roles and imports. Imports and Include are helpful to create/break up multiple small files of a massive playbook. Roles are primarily used to manage various tasks in a package including handlers, variables, plug-ins and other modules. They can also be uploaded and shared by Ansible Galaxy.

Q17. How to copy files into a target host recursively?

Ans: Ansible’s Copy module has a recursive parameter mostly efficiently used to synchronize modules that wraps rsync. The command to synchronize modules is as follows: -name: Copy over h5bp configuration Synchronize: mode=pull src=/tmp/server-configs-nginx/{{ item }} dest=/etc/nginx/{{ item }} with_items: – “mime. types” – “h5bp/.” Copying remote to remote use the same command as a delegate to and current inventory_host (remote source and remote destination respectively).