L1 Ansible Introduction

1、What is Ansible

It's a simple automation language that can perfectly describe an IT application infrastructure in Ansible Playbooks.

It's an automation engine that runs Ansible Playbooks.

Ansible Tower by Red Hat is an enterprise framework for controlling, securing and managing your Ansible automation with a UI and restful API.

2、Why Ansible

2-1 Simple

Human readable automation
No special coding skills needed
Tasks executed in order
Get executed quickly

2-2 Powerful

App deployment
Configuration management
Workflow orchestration
Orchestrate the app life cycle

2-3 Agentless

Agentless architecture
Uses OpenSSH $ WinRM
No agent to exploit or update
More efficient & more secure

3、What Can I use ansible to do

Config management
App Deployment
Provision
Continuous Delivery
Security & Compliance
Orchestration

4、Ansible Architecture

Alt Image Text

4-1 MODULES

Modules control systems resources, packages, files or nearly anything else
Over 450 ship with Ansible
Enable regular users to easily work with complex systems
But more on these later...

5、Where go get it and how to install

5-1 Os packages

EPEL
APT

5-2 Also from

Pypi
Sources (via Github)

6、Ansible lanaguage basics

6-1 playbooks

Plain-text YAML files that describe the desired state of something
Human and machine readable
Can be used to build entire application environments

6-2 variables

There are many different ways to source variables

Playbooks
Files
Inventories(group vars, host vars)
Command line
Discovered variables(fact)
Ansible Tower

6-3 Inventories

Static lines of servers
Ranges
Other custom things
Dynamic list of servers: AWS, Azure, GCP. etc

6-4 Basic of playbooks

Playbooks contain plays
Plays contain tasks
Tasks call modules
Tasks run sequentially
Handlers are tiggered by tasks, and are run once, at the end of plays

---
- name: install and start apache 
  hosts: web 
  remote_user: justin 
  become_method: sudo  
  become_user: root
  vars: 
    http_port: 80 
    max_clients: 200 

  tasks: 
  - name: install httpd 
    yum: name=httpd state=latest 
  - name: write apache config file 
    template: src=srv/httpd.j2 dest=/etc/httpd.conf 
    notify: 
    - restart apache 
  - name: start httpd 
    service: name=httpd state=running 

  handlers: 
  - name: restart apache 
  service: name=httpd state=restarted

6-5 MODULES

There are over 450 Ansible-provided modules that automate nearly every part of your environment

Standard structure:

module: directivel=value directive2=value

7、Ansible Simple Usage

7-1 Advanced Ansible Playbook Capabilities

Ansible has many different ways to alter how Playbooks run:

with items, failed when, changed when, until, ignore errors

http://docs.ansible.com/ansible/playbooks_specialiopics.html

Ansible Roles are a special kind of Playbook that are fully self-contained with tasks, variables, configurations templates, and other supporting files.

http://docs.ansible.tom/ansible/playbooks_roles.html

7-2 Using AD-Hoc Commands

Runs a command or calls module directory from the command line, no Playbook required

$ ansible <inventory> <options> 
$ ansible web -a /bin/date 
$ ansible web -m ping 
$ ansible web -m yum -a "name=openssl state=latest"

7-3 Running Playbooks

Runs a playbook on selected inventories from the command line

$ ansible-playbook <options> 
$ ansible-playbook my-playbook.yml

7-4 CHECK MODE `-C`

Dry-run for ad-hoc commands and Playbooks

Validate Playbook runs before making state changes on target systems

$ ansible web -C -m yum -a "name=httpd state=latest" 
$ ansible-playbook -C my-playbook.yml

7-5 Ansible Tower