ACI Power Deployment Tool – Update!

It’s been a long time! But, I’m back with some good news — at least if you care about ACI and the power deployment tool I’ve previously written about.

The tool itself was rather crude, and really my first attempt at anything substantive with python. I think functionally its been fantastic, but was certainly lacking in finesse! Well, over the past however long since I released it into the world, I’ve got a major, major update to write about!

I’ve been basically making minor enhancement to the tool since the last update in terms of functionality, however there have also been some pretty drastic improvements to the code structure. For a time we were using this stuff internally at work and I couldn’t really share all of that, though I did try to keep at least the baseline functionality updates rolling to Github (poorly, more on that later).

Now, however, we are done with our internal stuff and I’m releasing the far, far, superior version of pdt into the wild. The primary improvement here is that instead of a gargantuan mess of multi-line strings in the main library, I’ve moved to real live json files (whoa crazy idea huh!) and jinja2 templating. This cleaned up the main code base quite a bit. I’ve also been doing my best to slowly add in error handling throughout — starting with simple stuff like validating integers are integers, and the status input is actually a valid status! I’ve also added some basic error handling to improve any re-transmission errors — particularly on the ACI simulators (which yes, I know, are not publically available unfortunately) the sims will fail — I guess running out of memory or cpu, or just some internal throttling thing… in any case, the tool now will simply pause and re-attempt if this occurs.

I’ve picked apart a fair amount of the methods and cleaned things up and made them much more granular as well — particularly for Bridge Domains… before the code was a bit of a mess… one big BD method, but now its been broken down into three smaller bits which gives us much more flexibility and granularity of config.

One important piece which I eluded to a bit earlier… I’m now attempting to get my life together and actually learn how to use Github properly! It’s a bit embarrassing that I really had never done anything but delete repos and add it back with updated files. Not exactly stellar use of the tool! But hey, never too late to learn, so I’m doing my best to use Github in a more correct way (still a long way to go!!). So for now, I’ll probably always have a master and a dev branch. I’ll be using the dev branch pretty recklessly, updating whenever I damn well please! Whenever I feel like I get things to a reasonable place — stability wise, functionally, or whatever else — i’ll merge the dev branch into the master. Then ill start the whole thing over again! I’d also love to have contributors on the project if possible. I know it’s a pretty niche thing, but that would be good fun, and would be great to learn from some other folks about how to do all this stuff correctly! So, if you’re bored, feel free to make some pull requests and we’ll get to crackin’! For now, happy ACI’ing, hope some folks get good use out of the tool!


You can find the tool here:

ACI Power Deployment Tool (acipdt)

I’ve been spending a lot of my free time working on a little side project with Python. Rather than waxing on about it, I’ll just post a very quick and dirty video, and the that will accompany my tool.

You can find the video here. Note that the issue (which worked out as a decent demo) in the video where there were a bunch of 400 errors has been fixed — you can blame silly Python sets not being ordered!

You can find the acitool library here.

## Synopsis

ACIPDT – or ACI Power Deployment Tool – is a Python library that is intended to be used for network engineers deploying an ACI fabric. ACIPDT is very much early alpha, later releases should add additional features/functionality as well as optimization and improved error handling.

## Overview

The “SDN” (hate the term, but it applies) movement has brought a great deal of discussion to the idea of how a network engineer deploys networking equipment. Historically text files, or perhaps macros in Excel have been used as templates for new deployments, and good old-fashioned copy/paste has been the actual deployment vehicle. Among other things, SDN is attempting to change this. With SDN we (networking folk) have been given APIs! However, most network engineers, myself included, have no idea what to do with said APIs.

Cisco ACI, as with the other networky “SDN products,” in the market have provided some nifty tools in order to begin the journey into this API driven next-generation network world, but the bar to entry in any meaningful way is still rather high. In example, ACI provides an API inspector, which displays the XML or JSON payloads that are configuring the ACI fabric, however the payload on its own of course doesn’t do much for a network guy – where am I supposed to paste that into? What became clear to me is that Postman was the obvious answer. Postman is a great tool for getting started with an API, and I have used it extensively with ACI, even to the point of deploying an entire fabric in 2 minutes with a handful of Postman collections. However…

Postman left much to be desired. I’m fairly certain that the way in which I was using it was never really the intended use case. In order to keep the collections to a reasonable size, which in turn kept spreadsheets relatively organized (spreadsheets contained the data to insert as a variable in the payloads), but then I had nine collections to run, which meant nine spreadsheets. On top of all of that, there was very little feedback in terms of even simple success/fail per post — and even if you captured that output, there would be things that would fail no matter what due to the way the spreadsheet was piping in variables (perhaps more on that later, maybe its just how I was using it).

The result of this frustration is the ACIPDT. My intention is to re-create the functionality that I have used Postman for in Python. In doing so, the goal is to have a single spreadsheet (source of data, could be anything but a spreadsheet is easy), to run a single script, and to have valuable feedback about the success or failure of each and every POST. ACIPDT itself is not a script that will configure your ACI fabric, but is instead a library that contains ReST calls that will configure the most common deployment scenarios. In addition to the library itself, I have created a very simple script to ingest a spreadsheet that contains the actual configuration data and pass the data to the appropriate method in the library.

Key features:
– Have a library that is de-coupled from any deployment type of script.
– This was a goal after early attempts became very intertwined and I was unable to cleanly separate the simple ReST call/payload from the rest of the script.
– Run one script that references one source of data.
– This is more relevant to the run script than it is to the library, but it was taken into consideration when creating the library. A single spreadsheet (with multiple tabs) is used to house all data, is parsed in the run script, then data is passed as kwargs to the appropriate methods for deployment.
– Have discreet configuration items.
– Ensure that an Interface Profile on an L3 Out can be modified without deleting/re-creating the parent object. While this library/script is intended for deployments where this is likely not a big deal, it was at any rate a design goal.
– Capture the status of every single call.
– Each method returns a status code. The run script simply enters this data into the Excel spreadsheet at the appropriate line so you know which POSTs failed and which ones succeeded. This is a simplistic status check, but is leaps better than I was getting with Postman.

## Resources

I believe the code to be relatively straight-forward (and I am very not good at Python), and have provided comments ahead of every method in the library to document what is acceptable to pass to the method. As this is really just a pet project on the weekends, that’s probably about it from a resources perspective. Feel free to tweet at me (@carl_niger) if you run into any issues or have a burning desire for a feature add.

## Code Example

# Import acidpt from the acitool library
from acitool import acipdt
# Initialize the FabLogin class with the APIC IP, username, and password
fablogin = acipdt.FabLogin(apic, user, pword)
# Login to the fabric and capture the challenge cookie
cookies = fablogin.login()
# Initialize the Fabric Pod Policy class with the APIC IP and the returned cookies from the login class
podpol = acipdt.FabPodPol(apic, cookies)
# Configure an NTP server of
status = podpol.ntp('', 'created,modified')

## Getting Started

To get started, unzip the zip file and place the entire contents in a directory in your Python path. For me (using OSX), I placed the folder in /usr/local/lib/python2.7/. You can then import as outlined in the code example above.

## Disclaimer

This is NOT fancy code. It is probably not even “good” code. It does work (for me at least!) though.