DevOps with Ansible: Working with Ansible Features

Ansible Modules:
===============
Ping module
 #ansible webservers -m ping -u root -i hosts
Service module -
 #ansible webservers -m service -a "name=nginx state=restarted" -u root -i hosts
Shell module -
 # ansible webservers -m shell -a "sleep 2s && reboot & executable=/bin/bash" -u root -i hosts

Manual for all the modules

#ansible-doc <module name>
#ansible-doc service

To list all the ansible module
#ansible-doc -l


Ansible command Modules:
=======================
Raw Module - Use for bootstrap server which don't have python installed
#ansible ntpservers -m raw -a "test -e /usr/bin/python || (yum update && yum install python)" -u root -i hosts
#ansible ntpservers -a "who -r" -o -u root -i hosts

Shell Module - To redirect the shell commands
#anisble ntpservers -m shell -a "ps -aux > /tmp/ps.out" -u root -i hosts



Ansible Plugins:
===============
Plugins are pieces of code that augment Ansible's core functionality.
Ansible uses a plugin architecture to enable a rich, flexible and expandable feature set.

Action Plugins, Cache plugins, Inventory Plugins, Lookup Plugins, Vars Plugins, Shell Plugins


Lookup Plugins -
 # ansible app -m fetch -a "src='~/.ssh/id_rsa.pub' dest='buffer/{{inventory_hostname}}-id_rsa.pub' flat='yes'" -i ansible_hosts -b --become-user=weblogic
 # ansible genf -m authorized_key -a "user=root exclusive=no key='{{ lookup('file', '~/.ssh/id_rsa.pub') }}' "
 # ansible app -m authorized_key -a "user='weblogic' state='present' key='{{ lookup('file','buffer/mwiapp01-id_rsa.pub')}}'" --limit=mwiapp02 -i ansible_hosts -b --become-user=weblogic

Inventory Plugins -
 https://docs.ansible.com/ansible/latest/plugins/inventory.html

++++++++++Inventory.yml+++++++++++
 plugin: constructed
 strict: False
 groups:
   #basic name maching
   webservers: inventory_hostname.startwith('web')
   dbservers: inventory_hostname.startwith('db')
   ntpservers: inventory_hostname.startwith('ntp')
 
   #using ec2 'tags' presupposes AWS inventory
   test: "'test' in (ec2_tags|list)"
 
   #complex group membership
   multi_group: (group_names|intersection(['alpha', 'beta']))|length >= 2

 keyed_groups:
   # This creates a group per dist (dest_Centos, dist_Debian) and assigns hosts
   # with matching values using the default separator "-"
   - prefix: dist
     key: ansible_distribution
 
   # this creates a group aligned with ec2 architecture then assigns hosts to
   # those that have matching architectures (arch_x86_64, arch_sparc...)
  - prefix: arch
    key: ec2_architecture
++++++++++++++++++++++++++++++++++++++++++

 #ansible-iventory - i hosts -i inventory.yml --list
 #ansible-iventory - i hosts -i inventory.yml --graph


Ansible Filters:
===============
https://docs.ansible.com/ansible/latest/user_guide/playbooks_filters.html



Ansible Patterns:
================
 #ansible webservers:dbservers -m ping -u root -i hosts
 #ansible webserver[0] -m ping -u root -i hosts
 #ansible "dbservers:&staging" -m ping -u root -i hosts
 #ansible "dbservers:dbservers:&staging:!east" -m ping -u root -i hosts
 #ansible "~(web|db)servers" -m ping -u root -i hosts

Command Line Tools:
==================
https://docs.ansible.com/ansible/latest/user_guide/command_line_tools.html

 To view the ansible configuration from files
 #ansible-config  view

 To get into the console for all the node
 #ansible-console all -u root

 To view manual page
 #ansible-doc -l -t lookup
 #ansible-doc ping

 To dump or view the inventory
 #ansible-inventory -i hosts --graph
 #ansible-inventory -i hosts --list


Network scaling Automation:
==========================

Ansible Tower
 Includes important Ansible feature
 Complements the mail Ansible application
 Adds a comprehensive web-based UI
 Powerful for features rendered graphically
  Read-time node monitoring
 Visual tool reduces indimidation factor

Ansible Tower Main Features
 Role-based access control
 Simplified portal view mode
 Job scheduling
 Tower Dashboard
 REST API
 Cloud Integration

Ansible
 IT automation and configuration management
  Network automation
  Cloud infrastructure integration
 Agentless architecture
  Simple
  Secure
 Extensible 
 Comprehensive
 Agentless Architecture
  SSH,Netconf,eAPI,NX-API
  Centralized automation initiatives
  Security compliance
  Dyanamic inventory
  Use Cases
   Grabbing device configurations
    Save collection of configurations
   Push Device configurations
   Upgrade devices

Ansible Tower install:
=====================
 umask 022 - Need to set
 Minimum 4GB RAM need