* What is the different between a soft link and hard link?
```
hard link is the same file, using the same inode.
soft link is a shortcut to another file, using a different inode.
soft links can be created between different file systems while
hard link can be created only within the same file system.
```
* How to run a process in background and why to do that in the first place?
```
You can achieve that by specifying & at end of the command.
As to Why? since some commands/processes can take a lot of time to finish
execution or run forever
```
* What signal is used when you run 'kill <processid>'?
```
The default signal is SIGTERM (15). This signal kills
process gracefully which means it allows it to save current
state configuration.
followup questions:
what is SIGKILL?
what other signals there are?
```
## Ansible
* Describe each of the following components in Ansible, including the relationship between them:
* Task
* Module
* Play
* Playbook
* Role
```
Task – a call to a specific Ansible module
Module – the actual unit of code executed by Ansible on your own host or a remote host. Modules are indexed by category (database, file, network, …) and also referred as task plugins.
Play – One or more tasks executed on a given host(s)
Playbook – One or more plays. Each play can be executed on the same or different hosts
Role – Ansible roles allows you to group resources based on certain functionality/service such that they can be easily reused. In a role, you have directories for variables, defaults, files, templates, handlers, tasks, and metadata. You can then use the role by simply specifying it in your playbook.
```
* Write a task to create the directory ‘/tmp/new_directory’
```
- name: Create a new directory
file:
path: "/tmp/new_directory"
state: directory
```
* What would be the result of the following play?
```
---
- name: Print information about my host
hosts: localhost
gather_facts: 'no'
tasks:
- name: Print hostname
debug:
msg: "It's me, {{ ansible_hostname }}"
```
```
When given a written code, always inspect it thoroughly. If your answer is “this will fail” then you are right. We are using a fact (ansible_hostname), which is a gathered piece of information from the host we are running on. But in this case, we disabled facts gathering (gather_facts: no) so the variable would be undefined which will result in failure.
```
* Write a playbook to install ‘zlib’ and ‘vim’ on all hosts if the file ‘/tmp/mario’ exists on the system.
```
---
- hosts: all
vars:
mario_file: /tmp/mario
package_list:
- 'zlib'
- 'vim'
tasks:
- name: Check for mario file
stat:
path: "{{ mario_file }}"
register: mario_f
- name: Install zlib and vim if mario file exists
become: "yes"
package:
name: "{{ item }}"
state: present
with_items: "{{ package_list }}"
when: mario_f.stat.exists
```
* Write a playbook to deploy the file ‘/tmp/system_info’ on all hosts except for controllers group, with the following content
```
I'm <HOSTNAME> and my operating system is <OS>
```
replace <HOSTNAME> and <OS> with the actual data for the specific host you are running on
The playbook to deploy the system_info file
```
---
- name: Deploy /tmp/system_info file
hosts: all:!controllers
tasks:
- name: Deploy /tmp/system_info
template:
src: system_info.j2
dest: /tmp/system_info
```
The content of the system_info.j2 template
```
# {{ ansible_managed }}
I'm {{ ansible_hostname }} and my operating system is {{ ansible_distribution }
