Add Linux and Ansible questions

README.md

@@ -3,9 +3,10 @@
 
 ## Table of Contents
 
-  1. [Jenkins Questions](#jenkins)
-  1. [AWS Questions](#aws)
-  1. [Network Questions](#network)
+  1. [Jenkins](#jenkins)
+  1. [AWS](#aws)
+  1. [Network](#network)
+    4. [Linux](#linux)
 
 
 
@@ -64,6 +65,7 @@
 - What objects in S3 consists of?
   - Another way to ask it: explain key, value, version id and metadata in context of objects
 - Explain data consistency
+- Can you host dynamic websites on s3? what about static websites?
 
 ###### CloudFront
 
@@ -75,7 +77,141 @@
 - What delivery methods available for the user with CDN?
 - True or False? object are cached for the life of TTL
 
+
+
 ## Network
 
 Network questions can be found [here](https://github.com/bregman-arie/computer-networking/blob/master/interview_questions/README.md)
 
+
+
+## Linux
+
+* 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 <process id>'?
+```
+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 }
+```
+