Network automation: Ansible pushes the config

The idea

Network automation writes each router's wanted configuration down once, as files, and lets a tool push it. Here Ansible, on controlNode, gives officeRouter and branchRouter the static routes that let the laptop reach webServer, then catches a change made by hand.

Steps

1. The routers know only their own networks

   Start from nothing, so every route you see later is Ansible's work. Ping webServer from the laptop, then print officeRouter's running config: what its routing software, FRR, runs now.

   laptop:~# ping -c 2 -W 1 10.0.2.10
   officeRouter:~# vtysh -c 'show running-config'

2. The inventory: what Ansible manages

   Ansible needs to know which devices it manages and how to log in to them: that list is the inventory, devices in groups. Read it, then check Ansible can manage the routers group.

   controlNode:~# cat /etc/ansible/hosts.yml
   controlNode:~# ansible routers -m ping