Network Automation and Undifferentiated Heavy Lifting
I got this tweet after publishing the “use Ansible to execute a single command on all routers” blog post (and a few similar comments on the blog post itself)
Or use Python, Netmiko and a simple For loop
I never cease to be amazed by the urge to do undifferentiated heavy lifting in the IT industry.
Read more ...Cisco Live US 2017 – The Plan So Far
Put it on your calendar. Cisco Live US is June 25 – 29, 2017, in Las Vegas. This is the largest conference I go to every year, and it’s the highlight of my professional year. I’ve been going for a few years now and enjoy it for the content and camaraderie. What are we doing this year?
We’ll fly in on Friday again and do something. No idea what, but I imagine we’ll throw out an invitation for dinner to the public and meet somewhere. If you’re going to be in town, let me know, and we’ll meet up.
The Saturday Adventure was going to be ham radio related since that’s ARRL Field Day. I reached out to the Las Vegas ham club, and they told me that the clubs out there all go to the top of a mountain to operate. The problem : that mountain is 44.8 miles away from Mandalay. That’s one helluvan Uber ride, so that’s out. I looked at some other epic sites like the Grand Canyon and Hoover Dam, but, based on past participation, the time requirements for those don’t make the cut for the group. We probably need to meet Continue reading
Launching an Open Source Book Project
In my list of planned 2017 projects, I mentioned that one thing I’d like to do this year is launch an open source book project. Well, I’m excited to announce The Open vSwitch Cookbook, an Apache 2.0-licensed book project aimed at providing “how to” recipes for Open vSwitch (OVS).
Portions of the book are already available, with more content being added soon (more on that in a moment).
I’m using GitBook as the publishing platform; this allows me to write in Markdown and publish to a variety of formats. I’ll only be publishing to HTML at first; other formats may come down the road. I chose GitBook for a few reasons:
- It’s free for open source projects. This book, as well as the software that is its focus, are both open source projects.
- As I mentioned already, I can use Markdown for all the content.
- It allows me to store the book in a Git repository and use standard Git workflows.
I decided against using GitBook to host the Git repository for the book. Instead, the book’s source is found on GitHub. This enables collaboration on the book’s content—an aspect of this project that I think Continue reading
Worth Reading: ARM gains a foothold in China
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Reaction; Do we really need a new Internet?
The other day several of us were gathered in a conference room on the 17th floor of the LinkedIn building in San Francisco, looking out of the windows as we discussed some various technical matters. All around us, there were new buildings under construction, with that tall towering crane anchored to the building in several places. We wondered how that crane was built, and considered how precise the building process seemed to be to the complete mess building a network seems to be.
And then, this week, I ran across a couple of articles arguing that we need a new Internet. For instance—
What we really have today is a Prototype Internet. It has shown us what is possible when we have a cheap and ubiquitous digital infrastructure. Everyone who uses it has had joyous moments when they have spoken to family far away, found a hot new lover, discovered their perfect house, or booked a wonderful holiday somewhere exotic. For this, we should be grateful and have no regrets. Yet we have not only learned about the possibilities, but also about the problems. The Prototype Internet is not fit for purpose for the safety-critical and socially sensitive types of Continue reading
Worth Reading: Mud Slinging
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Free Webinar – DMZ Anywhere.Let’s talk about DMZ security design options
This is a free webinar but requires registration and seats are limited thus please register immediately. Webinar on Tuesday, February 28, 2017 7:00 PM – 8:30 PM AST. REGISTER Agenda Introduction to Security Zones What’s DMZ? Why do we need DMZ? Physical vs Logical Network Segmentation Emerging Technologies (Virtualization, Micro Segmentation) Benefits of DMZ Anywhere […]
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Python – Kirk Byers Course Week 3 Part 3
This post will describe the exercises and solutions for week three of Kirk Byers Python for Network Engineers.
The last exercise of the week is to create an IP address checker that checks the validity of an IP address. Here are the instructions:
IV. Create a script that checks the validity of an IP address. The IP address should be supplied on the command line.
A. Check that the IP address contains 4 octets.
B. The first octet must be between 1 - 223.
C. The first octet cannot be 127.
D. The IP address cannot be in the 169.254.X.X address space.
E. The last three octets must range between 0 - 255.
For output, print the IP and whether it is valid or not.
The IP address will be supplied through the command line. Like we’ve done before we are going to check the number of arguments supplied and exit the script if the number of arguments is not two. We need to import sys so that we can use sys.argv.
import sys
if len(sys.argv) != 2:
sys.exit("Usage: ./ip_checker.py <IP-ADDRESS>")
We’ll store the IP address as input as dotted decimal into the Continue reading
Using DCNM to Automate Cisco FabricPath Operations
In my final post on Cisco’s Data Center Network Manager (DCNM), I’m taking a look at the deployment capabilities and templating features which allow configuration to be deployed automatically to multiple devices. In its simplest case, this might be used to set a new local username / password on all devices in the fabric, but in theory it can be used for much more.
DCNM Scripting
Let’s get one thing straight right out of the gate: this ain’t no Jinja2 templating system. While DCNM’s templates support the use of variables and some basic loop and conditional structures, the syntax is fairly limited and the only real-time interaction with the device during the execution of the template amounts to a variable containing the output of the last command issued. There are also very few system variables provided to tell you what’s going on. For example I couldn’t find a variable containing the name of the current device; I had to issue a hostname command and evaluate the response in order to confirm which device I was connecting to. That said, with a little creativity and a lot of patience, it’s possible to develop scripts which do useful things to the fabric.