Network Automation: Ansible 101
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This document provides an overview and agenda for an Ansible 101 tutorial on network automation. It introduces Ansible concepts like playbooks, templates, variables, roles, and tasks. The tutorial will cover setting up an inventory and roles to generate network device configurations from templates using variables. It also discusses debugging Ansible and provides resources for learning more about network automation with Ansible.
![Hosts
● Group host addresses,
assign names, specify
variables, etc.
● Default is /etc/ansible/hosts
○ can override this easily
# EXAMPLE HOSTS LIST
[dev]
test-switch1 mgmt_ip=10.1.10.1
100.0.0.42
dev-router4
[prod]
mywebsite.com
172.16.0.56 name=dev42.prod
172.16.0.17](https://image.slidesharecdn.com/apricot-2017-ansible-1011488181813-170307004604/85/Network-Automation-Ansible-101-27-320.jpg)
![Inventory
● Allows you to pass in
specific data with
different playbooks
● Can specify hosts,
group vars, and
host-specific vars
● Can be accessed
across multiple roles
[EXAMPLE STRUCTURE]
myplaybook.yml
roles
inventory
hosts
group_vars
sites.yml](https://image.slidesharecdn.com/apricot-2017-ansible-1011488181813-170307004604/85/Network-Automation-Ansible-101-30-320.jpg)
![Roles
● A built-in structure for
compartmentalizing
● Roles make it easy /
clean to manage
execution
● Makes scaling and
collaboration easier!
[EXAMPLE STRUCTURE]
ansible
myplaybook.yml
roles
router
tasks
templates
switch
tasks](https://image.slidesharecdn.com/apricot-2017-ansible-1011488181813-170307004604/85/Network-Automation-Ansible-101-31-320.jpg)
![Running a play
ansible-playbook -i inventory myplaybook.yml
[command] [flag] [dir] [playbook]](https://image.slidesharecdn.com/apricot-2017-ansible-1011488181813-170307004604/85/Network-Automation-Ansible-101-47-320.jpg)
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Network Automation: Ansible 101
- 1. Network Automation: Ansible 101 APRICOT - Feb 28th, 2017 Bronwyn Lewis and Matt Peterson
- 2. Our assumptions ➔ New to the world of “DevOps” ➔ No prior Ansible knowledge ➔ Want to stop hand-crafting your network configs
- 3. Introduction ➔ Tutorial dependencies ➔ Introductions ➔ DevOps intro Agenda Tutorial ➔ Ansible intro & concepts ➔ Configuration templating ➔ Homework, next steps
- 5. Required knowledge 1. basic familiarity with the command line 2. use of a command line text editor (e.g. vim or nano) http://git.io/vZKZH
- 6. Required ➔ Linux, MacOS, or Win10 ➔ Python 2.7 ➔ Ansible 2.2 Technical requirements Recommendations ➔ Ubuntu 16.04 ➔ VM (VirtualBox, Vagrant) http://git.io/vZKZH
- 8. whois Bronwyn Lewis ● Technical advisor at SFMIX ● Networking, systems, and automation @ SFMIX and PCH for 3+ years ● Background in operations, project management, & international affairs
- 9. whois Matt Peterson ● Principal at Two P (network / systems) ● President at SFMIX (San Francisco IXP) ● Previously: Cumulus Networks, Tumblr, Square, Burning Man
- 10. Got {Net}DevOps?
- 11. DevOps ● Unite people and {organization appropriate} methods ○ Typically Developers & Operations staff ○ Shared service(s) availability responsibility ● Not a specific software program, license, certification
- 12. {Net}DevOps Leverage common DevOps tenants within Networking ● Configuration management (today’s focus) ● Infrastructure as code ● Reactive to infrastructure as a whole ● Consistency (sometimes viewed as transparency)
- 13. This is not a DevOps talk ● DevOps Kung Fu https://github.com/chef/devops-kungfu ● Phoenix Project / IT Revolution http://itrevolution.com/ ● DevOps Cafe podcast http://devopscafe.org/
- 14. Automation Tools while true ; do cat ~/.history ; done
- 15. Automation tools aren’t new ● Expect (1990) ● CFEngine (1993) ● Puppet (2005) ● NETCONF (2006) ● OpenConfig (2014) ● Lots of homegrown tools And much, much more...
- 17. What’s great about frameworks? Technical Benefits - procedural - repeatable - idempotent Other Benefits - open source (majority) - enterprise support - community
- 18. Why Ansible? 1. agent’less 2. low risk (run it locally) 3. small investment 4. easy to learn (abstraction!)
- 19. Abstraction instructions: what: update pkgs where: myServer1, myServer5 when: 23.00UTC reference: pkgs: openssh, apache
- 20. How Ansible works localhost *default assumption, unless module exists for target host OS * remote host(s) → SSH ←
- 21. (But we’re running it locally.) localhost
- 22. Terminology
- 23. WARNING! Visually boring, but important information packed slides ahead. (Sorry.)
- 24. JSON ● Data exchange format ● More powerful than CSV ○ Data can imply it’s a list, integer, string, etc. { "roles": { "noc": { "name": "Alice" }, "dev": { "name": "Ian" } } }
- 25. YAML ● Human readable data format, subset of JSON ● Always starts with --- ● Filename extension .yml or .yaml # EXAMPLE DATA FILE 1 --- roles: - { who: dev, name: Ian } - { who: noc, name: Alice } # EXAMPLE DATA FILE 2 --- roles: noc: name: Alice dev: name: Ian
- 26. Jinja2 ● Python template engine ● Enumerates files using variable data ● Supports conditionals: ○ If statements ○ Loops ○ Piping ● Ansible standard file extension .j2 # EXAMPLE TEMPLATE Employees: {% for k,v in roles %} Role: {% k %} Name: {% v %} {% endfor %}
- 27. Hosts ● Group host addresses, assign names, specify variables, etc. ● Default is /etc/ansible/hosts ○ can override this easily # EXAMPLE HOSTS LIST [dev] test-switch1 mgmt_ip=10.1.10.1 100.0.0.42 dev-router4 [prod] mywebsite.com 172.16.0.56 name=dev42.prod 172.16.0.17
- 28. Playbooks ● Specifies execution ● Single or multiple OK ● You can write all tasks and vars in a playbook... ○ … but not recommended --- - name: Generate configs hosts: localhost gather_facts: no roles: - router - switch
- 29. Facts ● Gathers information on the remote host(s) ○ Hardware, OS, uptime, MAC address & more ● You can use this info like a regular variable data point # EXAMPLE SYSTEM FACTS "ansible_architecture": "x86_64", "ansible_bios_date": "09/20/2012", "ansible_bios_version": "6.00",
- 30. Inventory ● Allows you to pass in specific data with different playbooks ● Can specify hosts, group vars, and host-specific vars ● Can be accessed across multiple roles [EXAMPLE STRUCTURE] myplaybook.yml roles inventory hosts group_vars sites.yml
- 31. Roles ● A built-in structure for compartmentalizing ● Roles make it easy / clean to manage execution ● Makes scaling and collaboration easier! [EXAMPLE STRUCTURE] ansible myplaybook.yml roles router tasks templates switch tasks
- 32. Hands-on
- 33. General outline ● Inventory + Roles ● Variables ● Templates ○ IP Address Filter ● Tasks ● Hosts ● Playbook
- 34. Hello world
- 38. Structure ├── myplaybook.yml ├── inventory │ ├── group_vars │ │ └── sites.yml │ └── hosts └── roles ├── router │ ├── tasks │ │ └── main.yml │ ├── templates │ │ └── template1.j2 │ └── vars │ └── main.yml └── switch ● Lots of ways to structure ○ Use roles? ○ Use an inventory? ○ Global, group, host variables? ● Depends on your situation ● No “right” way
- 39. Reference files Copy these from workspace/reference/ config1: we’ll use this as our 1st template config2: we’ll use this as our 2nd template config1-dhcp: advanced example template config2-dhcp: advanced example template ipaddress: RFC 5737 IP addresses (for demo/docs) variables: we’ll use these as our demo vars
- 40. Inventory + roles ● Inventory is an easy way to share variables across roles, as well as managing hosts & host-specific variables ● Roles make managing multiple templates and sets of tasks easier by compartmentalizing them
- 41. Variables ● Variables can be formatted individually, as a flat list, as a dictionary, or as an array ● Specific formatting can vary ⚠ Formatting impacts how you pass variables into templates and tasks — be careful here! ⚠
- 42. Templates ● You can template anything! ● Lots of neat advanced features, including: ○ If, when, and for statements/loops ○ Variable manipulation via filters
- 43. Tasks ● Procedural list of actions to execute, which combines templates and vars ● Conditions can be included, and are based on vars (i.e., only do X when Y is present)
- 44. IP address filter ● The ipaddr() filter is included in Ansible 1.9< ● Provides an interface to the netaddr Python package; does a lot of neat things including: ○ subnet manipulation ○ address validation ○ address conversion ○ MAC address formatting
- 45. Hosts ● What host we should be running the tasks on - normally this would be a remote host, but for us: localhost
- 46. Playbook ● Brings it together: ○ Hosts ○ Roles ■ Tasks ■ Templates ○ Variables ● And executes! --- - name: Create files hosts: localhost connection: local gather_facts: no roles: - router
- 47. Running a play ansible-playbook -i inventory myplaybook.yml [command] [flag] [dir] [playbook]
- 49. And if it didn’t work... Common issues: ● Missing packages? ● Missing variables? ● Formatting weirdness? ● Typos? Ansible can provide clues.
- 50. Ansible Debugging 101 Common Ansible debugging issues include: One or more undefined variables: 'dict object' has no attribute 'hostname' One or more undefined variables: 'hostname' is undefined ERROR: Syntax Error while loading YAML script
- 51. So… what’s next? ● Think how you can apply this to your work ● Start small; doesn’t need to be overly complex ● Check out more resources...
- 52. Some resources ● http://jedelman.com/ ● https://blog.tylerc.me/ ● https://pynet.twb-tech.com/ ● http://packetpushers.net/ ● http://keepingitclassless.net/ ● http://ansible-tips-and-tricks.rtfd.org/ books blogs/sites … and more!
- 53. Join us for 102 after the break... ● Advanced templating techniques ● Inventory + advanced variable & hosts management ● Dynamic inventory ● And more!
- 54. Thanks! 1. Questions? Comments? 2. Come talk to us! 3. Email or tweet us [email protected] @bronwyn [email protected] @dorkmatt