Ansible inventory

inventory Features:-
1)Behavioral Parameters
2)Groups
3)Group of Groups
4)Assign Variables
5)Scaling Out using multiple files
6)Static/Dynamic
examples:-
cat /etc/ansible/ansible.cfg|grep -i inventory
[ansible@ansibleserver ~]$ cat /etc/ansible/ansible.cfg |grep -i inventory
inventory      = /etc/ansible/hosts

#cat /etc/ansible/hosts
10.25.12.11
10.25.12.10
10.25.12.13
[db]
10.25.12.10

[web]
10.25.12.13

[datacenter:children]
db
web

To know List of Ansible hosts:-
[ansible@ansibleserver ~]$ ansible all --list-hosts
  hosts (3):
    10.25.12.10
    10.25.12.11
    10.25.12.13
[ansible@ansibleserver ~]$ ansible db --list-hosts
  hosts (1):
    10.25.12.10
[ansible@ansibleserver ~]$ ansible web --list-hosts
  hosts (1):
    10.25.12.13
[ansible@ansibleserver ~]$ ansible datacenter --list-hosts
  hosts (2):
    10.25.12.10
    10.25.12.13

=================
we can create local inventories as well.
ex:-
[ansible@ansibleserver ~]$ cat inventory
10.25.12.13 ansible_ssh_user=ansible ansible_ssh_pass=ansible
[ansible@ansibleserver ~]$ ansible all -i inventory -m ping
10.25.12.13 | SUCCESS => {
    "changed": false,
    "ping": "pong"
}
[ansible@ansibleserver ~]$ ansible all -i inventory -a 'df -h'
10.25.12.13 | CHANGED | rc=0 >>
Filesystem             Size  Used Avail Use% Mounted on
/dev/mapper/rhel-root   18G  2.9G   15G  17% /
devtmpfs               481M     0  481M   0% /dev
tmpfs                  490M     0  490M   0% /dev/shm
tmpfs                  490M  6.9M  484M   2% /run
tmpfs                  490M     0  490M   0% /sys/fs/cgroup
/dev/sda1              497M  119M  379M  24% /boot

[ansible@ansibleserver ~]$ ansible all -i inventory -a 'hostname'
10.25.12.13 | CHANGED | rc=0 >>
clinet.example.com

==============
[ansible@ansibleserver ~]$ cat inventory
10.25.12.13 ansible_ssh_user=ansible ansible_ssh_pass=ansible
10.25.12.11 ansible_ssh_user=ansible ansible_ssh_pass=ansible ansible_python_interpreter=/usr/bin/python
[ansible@ansibleserver ~]$ ansible all -i inventory -a 'hostname'
10.25.12.11 | CHANGED | rc=0 >>
yumserver.example.com

10.25.12.13 | CHANGED | rc=0 >>
clinet.example.com

==============
Declaring inventory Varibles:-
[ansible@ansibleserver ~]$ cat inventory
10.25.12.13 ansible_ssh_user=ansible ansible_ssh_pass=ansible
10.25.12.11 ansible_ssh_user=ansible ansible_ssh_pass=ansible ansible_python_interpreter=/usr/bin/python
[db]
10.25.12.11

[web]
10.25.12.13

[datacenter:children]
db
web

[datacenter:vars]
ansible_ssh_user=student
ansible_ssh_pass=student
[ansible@ansibleserver ~]$

[ansible@ansibleserver ~]$ ansible datacenter -i inventory -m ping
10.25.12.11 | SUCCESS => {
    "changed": false,
    "ping": "pong"
}
10.25.12.13 | SUCCESS => {
    "changed": false,
    "ping": "pong"
}