Ansible Lab 2, Static Routing and Ansible AD-HOC Commands

Ansible Lab 2: Validating Router Connectivity and Static Routing with Ansible Automation

Welcome to Lab 2 in the Ansible Automation series. In this lab, we’re building on the basics covered in Lab 1 and taking it a step further by focusing on real-world reachability checks and basic routing configuration using Ansible playbooks.

This lab walks you through setting up your hosts file, testing device reachability with Ansible ad-hoc commands, viewing routing tables across Cisco routers, and applying a static default route where needed. The network environment simulates four routers at different Points of Presence (PoPs) — R1 through R4 — and represents a real service provider scenario.

Lab Scenario

You’re tasked with verifying and adjusting the routing configuration of four routers: R1, R2, R3, and R4. These routers have already been configured with management IPs and credentials:

– **IP Range:** 192.168.47.x 
– **Username:** YouTube 
– **Password:** YouTube1 
– **SSH Port:** 22

As part of this lab, you’ll use ad-hoc Ansible commands to verify SSH access and a set of playbooks to retrieve routing information and configure missing static routes.

Step 1: Ansible Inventory Setup

Start by creating the `hosts` inventory file:

[edge]
R1 ansible_host=192.168.47.21
R2 ansible_host=192.168.47.22
R3 ansible_host=192.168.47.23
R4 ansible_host=192.168.47.24

[edge:vars]
ansible_user=YouTube
ansible_ssh_pass=YouTube1
ansible_port=22
ansible_connection=network_cli
ansible_network_os=cisco.ios.ios

Save this file as `hosts` in your Ansible project directory.

Step 2: Test SSH Connectivity (Ad-Hoc)

We now run a simple Ansible ad-hoc command to validate SSH connectivity:

ansible all -m ping -i hosts

If all devices respond with `pong`, SSH is working.

From the video walkthrough, we saw a successful response from all four routers, confirming the inventory and credentials are valid.

Step 3: Show IP Routing Table

We’ll now use an Ansible playbook to retrieve the routing table using the `ios_command` module.

- name: Show Routing
  hosts: edge
  gather_facts: no
  tasks:
    - name: Run show ip route
      cisco.ios.ios_command:
        commands:
          - show ip route
      register: output

    - name: Display raw output
      debug:
        var: output.stdout_lines

Run the playbook with:

ansible-playbook -i hosts show-routing.yaml

The output shows full routing tables. From the video, R1 and R2 had a default route present, but R3 and R4 were missing one.

Step 4: Configure Static Default Routes

To fix R3 and R4, we push a default route to all devices. Since R1 and R2 already have the route, Ansible’s idempotent behaviour ensures it’s only applied where needed.

- name: Add Static Route
  hosts: edge
  gather_facts: no
  connection: network_cli

  tasks:
    - name: Add default route
      cisco.ios.ios_config:
        lines:
          - ip route 0.0.0.0 0.0.0.0 192.168.47.2

Run it with:

ansible-playbook -i hosts default-route.yaml

This adds the default route to R3 and R4, resolving their reachability issue.

Summary

In this lab we:

– Defined an Ansible inventory for four routers
– Validated SSH connectivity with `ping`
– Fetched the routing table via playbook
– Configured a default route where missing

This lab reinforces the benefits of Ansible’s idempotence and gives you confidence in controlling multiple Cisco devices simultaneously.