DeveloperWeek 2021 DeveloperWeek 2021
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PRO WORKSHOP (CloudWorld): How Cisco Embraced a DevOps Culture within Its Network Engineering Team

- PST
CloudWorld Stage E
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Stuart Clark
Cisco Systems, Network Automation Developer Evangelist

Stuart joined Cisco in May 2012 and worked on the Cisco Cloud security business unit for six year before joining Cisco DevNet as an Network Automation Developer Evangelist. Stuart's main focus is abstract network automation engineering designing and building global networks, data centres and peering. Enjoys exploring how APIs, code and automation can make the network more efficient, error free and scalable.

He is like Hugh Hefner... minus the mansion, the exotic cars, the girls, the magazine and the money. So basically, has a robe.


BUSINESS PROBLEM & CHALLENGE
Network automation was not well practiced or well understood inside our network engineering team, but was sorely needed. We needed to decrease effort and mistakes on daily management tasks by minimizing the direct human interaction with network devices. High on our priority list of goals, was improving network security by recognizing and fixing security vulnerabilities and increasing the network performance.

HOW WE OVERCAME THE CHALLENGE
We started by simplifying daily workflows, baselining our configurations and removing snowflakes. While this can be very labour-intensive at the outset when you’re working on a global scale in a highly critical customer environment, the long-term benefits far outweighed the labour.
Next, we created an inventory file which listed all network devices by type, model, location and IP address - this enabled us to retrieve info about devices and using network programming and automation, allowing us to deploy to all devices, or even a subset of devices (eg. only those in a specific area), depending on what was needed. The benefit to this is we avoided manual configuration and logging into hundreds of different devices to add configuration to each one.
Overcoming these two big challenges set us up for success and enabled us to deploy at a global scale. We lived by the mantra:

“If it’s not repeatable, it’s not automatable. And if it’s not automatable, it’s not scalable.”

LEARNINGS AND MEASURABLE OUTCOMES
So what did we learn? For starters, it can be hard to automate a use case or test in the same way you would if doing it manually. Testing that requires physical movement, for example losing service provider links or hardware failure is also a challenge, as automating something like that is very tricky. We also learned that code reviews are extremely important. Shared code ownership means the entire team can make changes anywhere, at any time.

And what we’re the measurable outcomes?

Faster deployment times - we were able to efficiently push changes to over 300 network devices and audit the configuration of our global network, taking the time to execute from days down to hours.
Removed the fear of large and complex network changes - the accuracy and efficiency with which we were able to deploy at scale, gave business and the leadership more confidence in subsequent large scale network changes and deployments.
Faster feedback on network changes - it allowed us to get reviews on network configuration changes with version control and peer review, treating infrastructure as code (IaC).
Helped with adhering to PSIRT/CSIRT challenging timeframes and security vulnerabilities.


Techniques used:
We started by simplifying daily workflows, baselining our configurations and removing snowflakes. Next, we created an inventory file which listed all network devices by type, model, location and IP address.

Metrics used:
Speed of deployment; speed of feedback on network changes; speed of adherence to PSIRT/CSIRT timeframes; confidence and buy-in from senior leadership on subsequent deployments!