##########ansible ###########

https://galaxy.ansible.com for ready made playbooks

Configuration management tool - to maintain medium size infra with automation

to install applications,configuration,updates and maintain so on

reduce management complexity

ssh public key & private key they communicate

pip install ansible(depends on python version)
yum -y epel-release( some packages of ansible )
yum -y install ansible

ansible --version

then generate public/private key in master

ssh-keygen

cd .ssh

then id_rsa & id_rsa.pub

place public key to the node by creating vi authorized_keys and put the public key

then copy to the node

ssh-copy-id alma252@nodeip

in master node where ansible is installed
go to /etc/ansible/hosts file
add webserver ip in hosts file

[webserver]
192.......

try checking first if its working on not

ansible -m ping webserver
if success then working

we can work with ansible in 2 ways

1. playbooks
2. ad-hoc (on the fly we are installing using adhoc commands)

lets do

ansible -m shell -a "yum -y install httpd" webserver

we can write a yaml file install multiple applications on the nodes and run the ansible playbook

go to node and give httpd --version to see if its installed

systemctl status httpd

we can also do the same from master (ansible -m shell -a "systemctl status httpd" webserver or ansible -m service -a "name=httpd state=started" webserver

what is playbook

set of instructions file to do a paticular tasks on target(host) or group of target(host)

How playbook works?

it works with modules (yum,service,file,etc...) and inventory file (/etc/ansible/hosts)

how playbook starts?

---

• name: sample playbook
  hosts: target hosts or hosts name specifed in (/etc/ansible/hosts)

let's do

cd ansible_playbooks

vi sample_playbook.yml

---

• name: sample playbook
  hosts: webserver
  tasks:
  • name: sample file -<------ this step specifies action
    file:
    path: /tmp/sample.txt
    owner: root
    mode: 0644
    state: touch
  • name: install apache
    yum: <----- using yum module
    name: httpd
    state: latest
  • name: start apache service
    service:
    name: httpd
    state: started
  • name: copy sample template file
    template:
    src: index.html
    dest: /var/www/html/

save and run the playbook in host machine

ansible-playbook sample-playbook.yml

check on node if its installed

next part if we want to group of tasks to be worked on node we come up with ansible roles

ansible role:
group of playbooks in one file,will help reduce code complexity,increase the code reusability

go to master

ansible-galaxy init lamp (lamp linux apache mysql php)
ls
tree

defaults - main.yml
files - handlers - main.yml (service stop/start)
meta - main.yml -
README.md
tasks -- main.yml( install apache)
templates
test -- inventory --- test.yml
vars -- main.yml

so we are placing

cd/ansible/tasks/

vi httpd.yml

---

• name: install apache(httpd)
  yum:
  two spaces name: httpd
  state: latest
• name: start apache
  service:
  name: httpd
  state: start
• name: copy index.html file
  copy:
  src: index.html
  dest: /var/www/html/

vi php.yml

---

• name: install php
  yum:
  name: php
  state: latest
• name: copy phpinfo file
  copy:
  src: phpinfo.php
  dest: /var/www/html
  notify: restart apache server

vi mysql.yml

• name: install mariadb
  yum:
  name: mariadb
  state: latest
• name: install mariadb server
  yum:
  name: mariadb-server
  state: latest
• name: install php_mysql
  yum:
  name: phpmysql
  state: latest
• name: start mariadb
  service:
  name: mariadb
  state: started

One thing to note till centos6 ----mysql after that name changed to mariadb centos7

(tasks will define in main.yml)

vi main.yml

---

tasks file for lamp

• include_tasks: httpd.yml
• include_tasks: php.yml
• include_tasks: mysql.yml

:wq!

go to files in ansible lamp directory

cd files
vi index.html

hello welcome

vi phpinfo.php

go to handlers (so here notify what we mentioned same we are mentioning here)

there will be main.yml

vi main.yml

---

handlers file for lamp

• name: restrat apache server
  service:
  name: httpd
  state: restarted

:wq!

cd ansible lamp

Try to check using ping to from ansible server to node

ansible -m ping lampserver

to confirm if we go to /etc/ansible/hosts file we can find

[lampserver]
172........

cd

ls

lamp directory

vi mylamp.yml

---

• hosts: lampserver
  become: true
  roles:

  • lamp

  :wq!

check the syntax

ansible-playbook mylamp.yml --syntax-check

next we can execute the playbook

ansible-playbook mylamp.yml

we go error in httpd.yml file

we need to mentioned state as started state: start

go to child node and verify