Inventory

Configuration files

Ansible chooses its configuration from one of several possible locations:

• The ANSIBLE_CONFIG environment variable (if set, its value is the path to the file)

• If it is not set, Ansible will look for the configuration file in the following places:

• ./ansible.cfg

  • In the Ansible command's current working directory

• ~/.ansible.cfg

  • As a "dot file" in the user's home directory, used if there is no ./ansible.cfg file

• /etc/ansible/ansible.cfg

  • The default configuration file if no other configuration file is found

• Host-based connection variables can be put into host_vars directory, syntax is different

• Group-based connection vairables can be put into group_vars directory, syntax is different

Example

# ansible.cfg file
[defaults]
inventory = ./inventory
remote_user = ansible
remote_port = 22
ask_pass = false

[privilege_escalation]
become = true
become_user = root
become_method = sudo
become_ask_pass = false

# host_vars/server1.domain.com
ansible_host: 192.0.2.104
ansible_port: 34102
ansible_user: root
ansible_become: false

# inventory yaml format
all:
  children:
    spines:
      hosts:
        spine[01:02]
    leafs:
      hosts:
        leaf[01:02]
    network:
      children
        spines
        leafs

# inventory INI format
[spines]
spine[01:02]

[leafs]
leaf[01:02]

[network:children]
spines
leafs

Dynamic Inventory

• Python Script in inventory_plugins in the same folder as playbook

from __future__ import (absolute_import, division, print_function)
__metaclass__ = type

DOCUMENTATION = r'''
    name: dyninv_csv_plugin
    plugin_type: inventory
    short_description: Returns Ansible inventory from CSV
    description: Returns Ansible inventory from CSV
    options:
      plugin:
          description: CSV Inventory
          required: true
          choices: ['dyninv_csv_plugin']
      path_to_inventory:
        description: Directory location of the CSV inventory
        required: true
      csv_file:
        description: File name of the CSV inventory file
        required: true
'''

from ansible.plugins.inventory import BaseInventoryPlugin
from ansible.errors import AnsibleError, AnsibleParserError
import csv


class InventoryModule(BaseInventoryPlugin):
    NAME = 'dyninv_csv_plugin'


    def verify_file(self, path):
        '''Return true/false if this is possibly a valid file for this plugin to
consume

        '''
        valid = False
        if super(InventoryModule, self).verify_file(path):
            # base class verifies that file exists and is readable by current
            # user
            if path.endswith(('csvinv.yaml',
                              'csvinv.yml')):
                valid = True
        return valid

    def _get_structured_inventory(self, inventory_file):
    
        #Initialize a dict
        inventory_data = {}
        #Read the CSV and add it to the dictionary
        with open(inventory_file, 'r') as fh:
            csvdict = csv.DictReader(fh)
            for rows in csvdict:
                hostname = rows['Host']
                inventory_data[hostname] = rows
        return inventory_data

    def _populate(self):
        '''Return the hosts and groups'''
        self.inventory_file = self.inv_dir + '/' + self.inv_file
        self.myinventory = self._get_structured_inventory(self.inventory_file)
        #Create the location, function and platform  groups
        sites = []
        for data in self.myinventory.values():
            if not data['Site'] in sites:
                sites.append(data['Site'])
        for site in sites:
            self.inventory.add_group(site)
        #Add the hosts to the groups
        for hostname,data in self.myinventory.items():
            self.inventory.add_host(host=hostname, group=data['Site'])
            self.inventory.set_variable(hostname, 'ansible_host', data['IP'])
            self.inventory.set_variable(hostname, 'ansible_network_os', data['OS'])
            
    
    def parse(self, inventory, loader, path, cache):
       '''Return dynamic inventory from source '''
       super(InventoryModule, self).parse(inventory, loader, path, cache)
       # Read the inventory YAML file
       self._read_config_data(path)
       try:
           # Store the options from the YAML file
           self.plugin = self.get_option('plugin')
           self.inv_dir = self.get_option('path_to_inventory')
           self.inv_file = self.get_option('csv_file')
       except Exception as e:
           raise AnsibleParserError(
               'All correct options required: {}'.format(e))
       # Call our internal helper to populate the dynamic inventory
       self._populate()

Yaml file to store information about inventory: csvinv.yml

plugin: dyninv_csv_plugin # Name of the plugin, match NAME in class InventoryModule in python file
path_to_inventory: . # Directory location of CSV file
csv_file: devices.csv # CSV File 

Sample CSV File: devices.csv

No,Host,Name,Description,IP,OS,Site
1,DCS1,Switch01,Switch 01 DC,10.10.10.1,ios,DC
2,DCS2,Switch02,Switch 02 DC,10.10.10.100,nxos,DC
3,DCS3,Switch03,Switch 03 DC,10.10.10.101,nxos,DC
4,DRS1,Switch04,Switch DR,10.11.12.5,iosxe,DR
5,LOS1,Switch05,Core switch,10.10.10.2,iosxe,Office

• List inventory: ansible-inventory -i csvinv.yml –-list -–playbook-dir=.

  • inventory_plugins is relative to playbook, so commands ansible-config and ansible-inventory will not identify the plugin without additional parameter –playbook-dir=.

Commands

• ansible --version or ansible-config --version: identifies which configuration file is currently being used

• ansible-inventory -y --list: display current inventory in YAML format

• ansible group --list-hosts: verify machine presence in inventory

• ansible-inventory [-i $inventoryfile] –list

• ansible-inventory [-i $inventoryfile] –graph [$group]

• ansible-inventory [-i $inventoryfile] –host [$host]