1. Python for Network Engineers
A Practical Guide for Getting Started
Jeremy Schulman
@nwkautomaniac

2. Jeremy Schulman @nwkautomaniac
Software Engineer, Network Automation Specialist
20 Years in Industry
Since 2012 exclusively focused on "network automation"
Other Roles:
Developer Advocate
Systems Engineer
Automation Architect
Open source contributor
@nwkautomaniac
Slides:
jeremyschulman
Github:
jeremyschulman

3. Obligatory Disclaimer
The views and opinions expressed in this presentation are Jeremy Schulman's and do not represent any employer past or present.
Reference materials provided in this presentation, such as links to external training sites, do not represent any form of recommendation.

4. Network Engineers need to competently use Python so that they can make, and make use of, power-tools that will improve their jobs.
These tools will not replace them.

5. Agenda Discussion Live coding Where to go from here ...
Realistic expectations
Getting started
Live coding
Jupyter Notebook - makes Python feel like a CLI
NetOps example exercises
Where to go from here ...

6. Managing Networks "Manual via CLI" "SNMP based products"
"Vendor Products"
"SDN"
"Orchestration Systems"
"DevOps"
"Network Automation"
"Network Engineers must become Software Engineers"

7. Managing Networks "Manual via CLI" "SNMP based products"
"Vendor Products"
"SDN"
"Orchestration Systems"
"DevOps"
"Network Automation"
"Network Engineers must become Software Engineers"

8. Learning any New Skill [1]
Novice
Competent
Proficient
Expert
Master
Experience over a long time
Use everyday concrete experiences, not abstract concepts
Attaining core competency requires instructor led training and / or directed tutorials
Jeremy's key takeaways:
Attaining proficient skill requires experience and knowledge that takes massive time investment
Continuous mentorship, peer-review, feedback, learning, experimentation
[1] "A FIVE-STAGE MODEL OF THE MENTAL ACTIVITIES INVOLVED IN DIRECTED SKILL ACQUISITION", STUART E. DREYFUS and HUBERT L. DREYFUS, 1980.

9. Systems are Risky and Complex Manage Distributed Network Services
Configuration Management
“config”
Situational Awareness
“show”
High Risk
Complex
Tasks
Low Risk
Simple
Distributed System
(blast radius > 1)
Host-Only
(blast radius = 1)

10. Where to start using Python
Configuration Management
“config”
Situational Awareness
“show”
High Risk
Complex
Tasks
Low Risk
Simple
"Your network is a crime scene, and you are the detective. You need better ways to investigate what happened, and prove guilt or innocence."
-- Jeremy
Distributed System
(blast radius > 1)
Host-Only
(blast radius = 1)

11. Make Python *feel* like being on a CLI
Live Coding
Make Python *feel* like being on a CLI

12. Jupyter Notebook Setup a Python virtual-environment
$ virtualenv playground
$ source playground/bin/activate
Install Jupyter notebook for Python 2.7
(playground)$ pip install ipython==5 jupyter
Install Jupyter notebook for Python 3
(playground)$ pip install jupyter

13. Jupyter Notebook Start Jupyter notebook system, will launch browser
(playground)$ jupyter notebook

14. Live Demo!

15. Where to go from here ...

16. Novice Topics Variables, duck-typing help(), type(), dir()
pretty-printing
Importing packages
List, Dictionary
Tuple, Set
Functions
For-loops
If / Then / Else
Working with files
JSON, YAML files
List Comprehensions
Dictionary Comprehensions
Set Comprehensions
Collections - Counter
Collections - defaultdict

17. Python Libraries ipaddress tabulate first tqdm requests collections
csv
json
yaml
gtextfsm
netmiko
napalm
lxml
paramiko
bidict
operator
itertools
chain

18. Next Steps Building Novice Skills Building Competency
Take formal Python courses
Global Knowledge
Subscribe to Python News
Dan Bader
Try PyCharm IDE (Integrated Development Environment)
Use Python every day
Use Jupyter notebook
Take industry classes
IpSpace
NetworkToCode
Kirk Byers
Free Cisco DevNet

19. Closing Thoughts
"A good network engineer is proficient at quickly becoming competent."
-- Derick Winkworth
Be patient. Set realistic goals, both with yourself and your management
Consider how long it took you to become a Senior Network Engineer
Senior network engineer == 5-8yrs, multiple domains, technology.

20. Jeremy Schulman @nwkautomaniac
Cheers!
Jeremy Schulman
@nwkautomaniac