Network Automation with Ansible

Chapter 6. Ansible Terminology and Getting Started

This chapter walks through many of the terms and key concepts that have been gradually introduced already in this report. These are terms such as inventory file, playbook, play, tasks, and modules. We also review a few other concepts that are helpful to be aware of when getting started with Ansible for network automation.

Please reference the following sample inventory file and playbook throughout this section, as they are continuously used in the examples that follow to convey what each Ansible term means.

Sample inventory:

# sample inventory file
# filename inventory

[all:vars]
user=admin
pwd=admin

[tor]
rack1-tor1   vendor=nxos
rack1-tor2   vendor=nxos
rack2-tor1   vendor=arista
rack2-tor2   vendor=arista

[core]
core1
core2

Sample playbook:

---
# sample playbook
# filename site.yml

  - name: PLAY 1 - Top of Rack (TOR) Switches
    hosts: tor
    connection: local

    tasks:
      - name: ENSURE VLAN 10 EXISTS ON CISCO TOR SWITCHES
        nxos_vlan:
          vlan_id=10
          name=WEB_VLAN
          host={{ inventory_hostname }}
          username=admin
          password=admin
        when: vendor == "nxos"

      - name: ENSURE VLAN 10 EXISTS ON ARISTA TOR SWITCHES
        eos_vlan:
          vlanid=10
          name=WEB_VLAN
          host={{ inventory_hostname }}
          username={{ user }}
          password={{ pwd }}
        when: vendor == "arista"

  - name: PLAY 2 - Core (TOR) Switches
    hosts: core
    connection: local

    tasks:
      - name: ENSURE VLANS EXIST IN CORE
        nxos_vlan:
          vlan_id={{ item }}
          host={{ inventory_hostname }}
          username={{ user }}
          password={{ pwd }}
        with_items:
          - 10
          - 20 ...