09 - ANSIBLE - Configuration Management

 ANSIBLE - Configuration Management

• Written in Python
• Work with push base mechanism (Synchronous)
• Not required any Agent
• SSH port 22 
• RHEL provides support
• Created own modules
• Task (like manifest or receipt in puppet/chef) required for configuration  -> written in YAML file
• State (Current to Desired State)
• Open Source and Enterprise
  

• Ansible Playbook  -> Role   (like cookbook in chef) for provisioning
• Playbook -> Role -> Tasks  ( define in .yaml file )

• Ansible Tower -> Like Puppet GUI

• Automation Engine
• Modules - Prewirtten resources like services, packages, execute system command, files (450 buit-in)
• Inventory  - Consist list of servers  (like site.pp in puppet)
• API - Interacting with hosts/Servers
• Plugins - manage functionality like networking - way of customization 
• CMDB - Optional tools for Configuration Management database

• Ansible Galaxy 

pre-written playbooks

https://galaxy.ansible.com

• Ansible Tags

Tasks -

Install ngnix tags:install

Start service 

Enable service

copy nginx.conf tags:config

Restart service tags:config

playbook -t config

• Py YAML: is a YAML parser and emitter for Python

ANSIBLE INSTALLATION 

1- Ansible Workstation

2 GB RAM

vagrant up

vagrant ssh

sudo su -

hostnamectl set-hostname ansiblewks.unix.in

bash

vi /etc/hosts

192.168.33.40 ansiblewks.unix.in

192.168.33.41 webserver.unix.in

192.168.33.42 application.unix.in

useradd devopsadm -G wheel

passwd devopsadm   

        visudo    ***** remove #  from wheel line

        su - devopsadm

        

       ** to verify sudo access

      sudo -l

** Now Install epel , python and pip 

sudo yum install -y epel-release

sudo yum install -y python-pip

pip --version

pip 8.1.2 from /usr/lib/python2.7/site-packages (python 2.7)

** Install the latest version of pip ( pip like yum )

pip install --upgrade pip

** Install Ansible

pip install ansible ## if required old version $pip install ansible==2.3.3

ansible --version

** Now create Server Inventory file

mkdir /etc/ansible

cd /etc/ansible

vi hosts

[ansbilewks]

192.168.33.40

[webserver]

192.168.33.41

[application]

192.168.33.42

** Run the List of Inventory

ansible all --list-hosts

ansible all -m ping

** Setup ssh key and password less access

### passwd root

ssh-keygen -t rsa

ls -ltra ~/.ssh

** 1 ** Reset password in Webserver and Application VM for push SSH key

ssh-copy-id 192.168.33.41 

ssh-copy-id 192.168.33.42

** Run command in webserver from ansible workstation

ansible webserver -a "hostname"

ansible webserver -a "uptime"

** copy host file from workstation to webserver

ansible webserver -m copy -a "src=/etc/hosts dest=/tmp/hosts"

        

          ** 2 *** Verify copy file in webserver

** search file module in google

** host file will be delete in webserver

ansible webserver -m file -a "dest=/tmp/hosts state=absent"

** Create Reposity and Common Role

mkdir  ansible-automation 

cd  ansible-automation

mkdir -p roles/common

cd roles/

        cd common

mkdir files handlers meta tasks templates vars

cd tasks

vi main.yml

---

- include: common_pkg.yml tags=commonpkg

vi common_pkg.yml

---

- name: install common dependencies

  action: >

    {{ ansible_pkg_mgr}} name={{ item }} state=present update_cache=yes

  with_items:

     - vim

     - git

     - sysstat

     - unzip

** create playbook in ansible-automation directory

cd ..

cd ..

cd ..

vi webservers.yml

---

- name: Setup webserver for our micro service

  hosts: webserver

  user: devopsadm

  roles: 

    - common

  become: true 

  

** run playbook

ansible-playbook webservers.yml

** 3 ** go to webserver and verify playbook installation

** Gather of list of all fact

ansible webserver -m setup

ansible webserver -m setup | grep ansible_virtualization_role

** Create a message of the day (MOTD) in webserver

cd roles

mkdir motd

cd motd

mkdir defaults tasks templates

cd tasks

vi main.yml

---

- name: Copy the MOTD file over the webserver

  template: 

    src: motd.j2

dest: /etc/motd

  tags:

    - motd_config

** create a banner - motd

cd ../defaults

vi main.yml

---

# Default ASCII art shown at the beginning of the motd

  motd_ascii_art: "     _              _ _     _\n    / \\   _ __  ___(_) |__ | | ___\n   / _ \\ | '_ \\/ __| | '_ \\| |/ _ \\\n  / ___ \\| | | \\__ \\ | |_) | |  __/\n /_/   \\_\\_| |_|___/_|_.__/|_|\\___|\n"

#

# # Default information to show under the ASCII art

  motd_info:

- " FQDN:    ": "{{ ansible_fqdn }}"

- " Distro:  ": "{{ ansible_distribution }} {{ ansible_distribution_version }} {{ ansible_distribution_release }}"

- " Virtual: ": "{{ 'YES' if ansible_virtualization_role == 'guest' else 'NO' }}\n"

- " CPUs:    ": "{{ ansible_processor_vcpus }}"

- " RAM:     ": "{{ (ansible_memtotal_mb / 1000) | round(1) }}GB"

cd ../templates

vi motd.j2

{{ motd_ascii_art }}

{% for item in motd_info %}

{% for key,value in item.iteritems() %}

{{ key }}{{ value }}

{% endfor %}

{% endfor %}

cd ..

cd ..

** modify webservers.yml file and mtod

vi webservers.yml

---

- name: Setup webserver for our micro service

  hosts: webserver

  user: devopsadm

  roles: 

    - common

    - motd

  become: true 

** dry run mode

ansible-playbook webservers.yml --check --diff

** run playbook

ansible-playbook webservers.yml

** 4 ** go to webserver and verify playbook installation

** Now install ngnix

** go to galaxy.ansible.com

** find nginx and download role or copy link

ansible-galaxy collection install nginixinc.nginx._core

cd ~/.ansible/

grep -ir nginx .

        cd collections/ansibles/ansible_collections/nginixinc/nginx/_core

[devopsadm@ansiblewks roles]$ pwd

/home/devopsadm/.ansible/collections/ansible_collections/nginxinc/nginx_core/roles [devopsadm@ansiblewks roles]$ ls -ltr total 12 drwxr-xr-x. 11 devopsadm devopsadm 4096 Dec 28 18:36 nginx_config drwxr-xr-x. 11 devopsadm devopsadm 4096 Dec 28 18:36 nginx drwxr-xr-x. 12 devopsadm devopsadm 4096 Dec 28 18:36 nginx_app_protect

cp -r nginx ~/ansible-automation/roles/

cd ~/ansible-automatio

** modify webserver.yml file and mtod role

vi webservers.yml

---

- name: Setup webserver for our micro service

  hosts: webserver

  user: devopsadm

  roles: 

    - common

    - motd

    - nginx

  become: true 

** run playbook

ansible-playbook webservers.yml

** 5 ** go to webserver and verify nginx installation

2 - Webserver - VM01

vagrant up

vagrant ssh

sudo su -

hostnamectl set-hostname webserver.unix.in

bash

vi /etc/hosts

192.168.33.40 ansiblewks.unix.in

192.168.33.41 webserver.unix.in

192.168.33.42 application.unix.in

useradd devopsadm -G wheel

passwd devopsadm   

        visudo    ***** remove #  from wheel line

        su - devopsadm

** 1 *** reset vagrant pwd for ssh key copy from ansiblewks

## passwd root

## passwd vagrant

** 2 *** 

cd /tmp

ls -ltr

  -rw-rw-r--- hosts

  

*** 3 *** check installation of vim, git , sysstat, unzip 

unzip

       vim

*** 4 *** check motd banner role

logout

vagrant ssh

*** 5 *** check ngnix running

ps -ef | grep nginix

3 - Application - VM02

vagrant up

vagrant ssh

sudo su -

hostnamectl set-hostname application.unix.in

bash

vi /etc/hosts

192.168.33.40 ansiblewks.unix.in

192.168.33.41 webserver.unix.in

192.168.33.42 application.unix.in

A playbook is simply a list of plays. The highest level of a playbook YAML is a list, and on that list, only two things are accepted: a play definition or the keyword import_playbook, which imports a list of plays from another playbook file, as if they were defined in that place of the calling file.

The playbook is also the only thing that can be called directly from ansible-playbook.

A task is, paraphrasing the manual, 'nothing more than a call to an ansible module'. That call definition, however, knows nothing of on which hosts it is supposed to run on.

The play is the element that ties tasks to the servers where they'll run. The key element here is the mandatory keyword hosts. This is the part of Ansible that tells which hosts are being affected and how.

So, the structure and behavior is as follows:

• Playbook: the highest level, just a list of plays
• Play: ties tasks to host lists
• Tasks: definition of a call to a module
• Besides tasks, a play may have pre-tasks, post-tasks and handlers, which are all task-like

A role is a different thing, as it is not defined within a playbook. Instead, they each have their own subdirectory under the directory roles. The objective of roles is to organize things. So, under the role's subdir, you can find tasks, handlers, files and templates, variables and defaults. All of these related to that specific role.

So, roles are an easy way to encapsulate and share Ansible information. You could have a subdir in templates per task, for example. But if you wanted to share that task, you'd have to pick the template as well. With roles, you can just zip the role dir and (almost) everything should be there.

Like a play, the role defines tasks and handlers. However, roles do not define on which hosts the role will be run. So roles must be referenced to from a play.

Roles can also declare dependencies (that is, references to other roles that need to be run before the declaring one).

A module is a reusable, standalone script that Ansible runs on your behalf, either locally or remotely. Modules interact with your local machine, an API, or a remote system to perform specific tasks like changing a database password or spinning up a cloud instance.