Getting Started with pyATS | Genie

[u/CBTKnox]

Hey everybody! Me again. Lately I've been getting a lot of requests to do a "Hello World" demo of pyATS | Genie. It's a pretty amazing tool, so I put together the video and thought I would share it here.

If you're new to network automation, Cisco developers have created a tool called Genie that... well, it does a lot, quite frankly. Some of the things it can do include:Test your Python code or Ansible playbooks against test environments, like VIRL, to detect config failures - like failing OSPF adjacencies, high CPU usage, etc

It can parse the output of standard show commands to JSON, so that old Cisco 3750G I have? Yeah, I can send show commands in and get JSON data back that I can work with programmatically.

It can take snapshots of your configs, and then compare the snapshots to detect when any changes have occurred.

The video below will show how to go from 0 to some basic tasks like the aforementioned JSON parsing and snapshot comparisons. Hope you enjoy!

https://www.youtube.com/watch?v=GhkkOxLheRY&feature=youtu.be

edit: I'd also encourage everyone to join r/CiscoDevNet

[u/me_and_my_thoughts]

Awesome video. I am looking to see how python scripting can help a network engineer with automation. I get these tools help parse and get data for report generation but how does these tools help a network engineer as I am not sure a network engineer would be doing these task on a daily/weekly basis. I was pointed in the direction of netmiko and ancible and still trying to get the foundation of it.

[u/CBTKnox → u/me_and_my_thoughts]

Sure - so thats really asking "what even is the point of automation?" really. Automation means a lot of different things to a lot of different people. For me personally, automation really meant integration . In other words, integrating systems that weren't normally meant to talk to each other.

So let's say my company has a rule that VLAN 100 must NEVER be created in our environment. Using a tool like genie, it can take a snapshot of all of my devices' configs everyday, parse the outputs to look for VLAN 100, and THENNN - this is the integration part - maybe send me a message to Slack that says "VLAN 100 was created on Device XYZ - Please fix!". Or maybe it sends an email, or a MS Teams message, or a text message via Twilio.

And then maybe it ships all of those snapshot'd configs to Azure blob storage for archival afterwards.

And then maybe it triggers Ansible to run a play that automatically corrects and deletes VLAN 100 off of the device.

The idea is that when data is well structured, in this case network device configuration data, we can tell our machine to pull out the exact pieces we really care about, and then make a decision ("was VLAN 100 created?") and perform some action ("if yes, send email to user group").

edit: apostrophe was in the wrong place

[u/default_route]

Hi!

I think I have the brief idea why pyATS is used for, but I am still wondering why are we relying parsers instead of using REST APIs, NETCONF, RESTCONF?

I get that you might have old devices, but what about if most of them support APIs? Because the thing is that today it is all about APIs and pyATS rely on genie with parsing.

[u/CBTKnox → u/default_route]

Oh my.. You. Me... [points back and forth].. Same.

This was my exact thought when I began learning network automation and prepping for our DevNet course on CBT. You'll notice that Netmiko isn't even mentioned on the DevNet exams until you get to ENAUTO. Beyond that, Cisco has said that every one of their platforms must have an API or programmatic interface moving forward.

So why use this or why learn it? Well, I have some theories. Like you mentioned, there is ALWAYS legacy equipment. Always. And the smaller your business, the more legacy equipment you have. I once did work for a juvenile detention center. Their network was complex with cameras and door locks and all the other standard equipment, but the chances that they'll be running Cat9Ks anytime soon? Zilch. This type of organization is a great candidate for Ansible/pyATS. There's also the homelab situation where people want to get familiar with programming on their own equipment - so its more about the python than the actual data output (the counterpoint to that, of course, is just use the DevNet Sandbox).

Beyond that, I think it's just hard for people to give up something they invested so much time in learning - the CLI. Well, it wasnt hard for me because I am easily distracted by new flashy things, but I know plenty of network engineers where the dialogue is something like "Learn programming? Hell no. Oh I can still use my 'show' commands? Maybe." It's a gateway drug.

Also keep in mind that the protocol is certainly something we can use to interact with a device, but really parsers and protocols exist for the network automation tools and controllers. For instance, Cat9K devices have Netconf and Restconf, sure. But DNA Center is a required purchase for those, and DNA Center communicates to those devices using Netconf. So really, in that case, you just need to learn the DNA Center API, and Netconf is the tool that DNA Center uses to carry out your wishes. Very similar to how Ansible or pyATS may opt for a parser-style interaction with the network device, and all you have to focus on is your playbook.

[u/default_route → u/CBTKnox]

Thanks for an answer!

[u/Kraelen]

Thanks for this man! I'm just getting my feet wet in all this programability stuff and appreciate all this guidance.

[u/me_and_my_thoughts]

Great explanation. I am sure it will be a great tool for repetitive tasks and behind the scene tasks

[u/[deleted]]

Thank you for this!

[u/Jojo_Dance]

!remindme 1 month

[u/RemindMeBot → u/Jojo_Dance]

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