Automating Network
Infrastructure : Ansible
Chinmay Biswas (AS10075)

Acknowledgement
I have prepared this presentation with the help of many books,
presentations, websites and blogs. I would like to express to deepest
appreciation and a sense of gratitude to my guide Imtiaz Rahman,
supervisor Simon Sohel Baroi and colleague Zobair khan.
Ansible was originally written by Michael DeHaan

Agenda
1. Why Automation?
2. About Ansible
3. Why Ansible?
4. How Ansible Works?
5. Install Ansible
6. Run Ansible
7. Demos

Why Automation?
• Reduce Human Errors
• Make the Network More Dynamic
• Simplify Network Management
• Reduce Risk

Automation Tools

Why Ansible?
Simple Powerful Agentless
• Download and Go
• Don’t need any programmer
• Save time and increase speed
• No Agents: Only an “Ansible Control”

About Ansible
• Automation and configuration management tool
• Open source
• Initially deploy for Linux in 2012
• Networking modules added in release 2.x
https://docs.ansible.com/ansible/latest/modules/list_of_network_modules.html

How Ansible Works?

Installation
• Required Linux Box
• Easy to Install
• Install guide:
https://docs.ansible.com/ansible/latest/installation_guide/index.html

Run Ansible
• ad-hoc Command
• Playbook

Run Ansible
ad-hoc Command: Run individually to perform quick functions
Use case:
• Just validate the uptime of 1 to 200 remote devices
• Just get the disk space of remote hosts
• Ping and validate if the server is alive and responds
• shutdown multiple remote hosts at a single command
* Not used for configuration management and deployment

Run Ansible
Playbook: Playbook tells Ansible what to
do, in other word you can send
commands to the remote
devices through playbook.
Module
Task
---
- hosts: router_bdnog11
gather_facts: false
connection: local
tasks:
- name: PUSH THE POLICY to DEVICE
ios_config:
provider: "{{ provider }}"
authorize: yes
src: CUSTOMER-1.txt
Play
Inventory: Hosts and groups of hosts

Demos
• Ansible 2.9.1
• bgpq3 0.1.35
• Ubuntu 18.04.3 LTS
• Cisco router with IOS-XE

Demos – List of works
1. Some Basic Configuration
2. Interface Configuration
3. Save Configuration
4. Auto Prefix Announcement

Demo-1 (Some Basic Configuration)
- name: BASIC CONFIGURATION
ios_config:
provider: "{{ provider }}"
authorize: yes
lines:
- aaa new-model
- aaa authentication login default local
- aaa authentication enable default enable
- no logging console
- no ip domain-lookup
- ipv6 unicast-routing
- ipv6 cef
- no ip source-route
- no ipv6 source-route
- snmp-server community C-DAC RO 99
- ntp server 192.168.0.250

Demo-2 (Interface Configuration)
- name: CONFIGURE INTERFACE SETTINGS
ios_config:
provider: "{{ provider }}"
authorize: yes
parents: interface FastEthernet2/0
lines:
- description Test Interface
- ip address 172.31.1.1 255.255.255.252
- ipv6 address 2001:db8:8::9/64
- no shutdown

Demo-3 (Save Configuration)
- name: IOS >> Save Configuration to NVRAM
ios_config:
provider: "{{ provider }}"
authorize: yes
save_when: always
register: output
- name: SHOW RUN COMMAND
ios_command:
provider: "{{ provider }}"
authorize: yes
commands: show run
register: print_output
- name: SAVE OUTPUT TO A FILE
copy: content="{{print_output.stdout[0]}}" dest="/home/gns3/inventory/backup-
configuration/{{inventory_hostname}}.txt"

Demo-4 (Auto Prefix Announcement)
bgpq3 – create the filtering (Prefix-List/AS-PATH)
Example:
bgpq3 -l CUSTOMER-1-Prefix -A -4 CUSTOMER-AS-SET > CUSTOMER-1.txt

Demo-4 (Auto Prefix Announcement)
Ansible – push that filter to Router (Prefix/AS-PATH)
- name: PUSH POLICY to DEVICE
ios_config:
provider: "{{ provider }}"
authorize: yes
src: CUSTOMER-1.txt
- name: BGP CONFIGURATION
ios_config:
provider: "{{ provider }}"
authorize: yes
parents: router bgp 10075
lines:
- neighbor 172.31.1.2 remote-as 63996
- neighbor 172.31.1.2 description TEST-BGP
- neighbor 172.31.1.2 activate
- neighbor 172.31.1.2 prefix-list CUSTOMER-1-Prefix in
- neighbor 172.31.1.2 prefix-list ALL-DENY out

Demo-4 (Auto Prefix Announcement)
Adding Into Crontab…..
BGPQ3 Cron:
# run five minutes after 11AM, every day
5 11 * * * /usr/bin/bgpq3 -l CUSTOMER-1-Prefix -A -4 CUSTOMER-AS-SET > CUSTOMER-1.txt
Ansible Cron:
# run ten minutes after 11PM, every day
10 11 * * * /usr/bin/ansible-playbook -i inventory playbook-bgp-policy.yml
https://drive.google.com/file/d/1A5EYGFKpny5ezy-abEqqtsO9PdYcUlRY/view?usp=sharing
Complete Playbook Link:

Observation
1. For IOS-XR Ansible version 2.9.1 is required
2. For IOS-XR bgpq3 version 0.1.35 is required
3. Careful about iptables, the Linux Firewall

Far to Go
1. Implementation with MikroTik
2. Implementation with IOS-XR, JUNOS etc
3. Ansible Roles
4. Ansible Tower [$$$]
5. More…

References
https://docs.ansible.com/
http://anastarsha.com/
https://imtiazrahman.com/
https://github.com/snar/bgpq3
https://www.ansible.com/success-stories/runnable
https://www.tutorialspoint.com/ansible/index.htm
https://medium.com/edureka/ansible-roles-78d48578aca1
https://www.rogerperkin.co.uk/network-automation-tools/
https://blog.technologent.com/7-good-reasons-network-automation
https://www.oreilly.com/learning/network-automation-with-ansible
https://www.middlewareinventory.com/blog/ansible-ad-hoc-command-examples-cheat-sheet/

chinmay.biswas@fiberathome.net