Building network automation solutions

A long while ago I decided to write an article explaining how you could run VMware NSX on ESXi servers with redundant connections to two top-of-rack switches on top of a layer-3-only fabric (a fabric with IP subnets and VLANs limited to a single top-of-rack switch). Turns out that’s Mission Impossible, so I put the article on the back burner and slowly forgot about it.

Well, not exactly. Every now and then my subconsciousness would kick it up and I’d figure out yet-another reason why it’s REALLY hard to do it right. After a while, I decided to try again, and completely rewrote the article. The first part is already online, more details coming (hopefully) soon.

Every few years someone within the ITU-T (the standard organization that mattered when we were still dealing with phones, virtual circuits and modems) realizes how obsolete they are and tries to hijack and/or fork the Internet protocol development. Their latest attempt is the “New IP” framework, and Geoff Huston did a great job completely tearing that stupidity apart in his May 2020 ISP column. My favorite quote:

It’s really not up to some crusty international committee to dictate future consumer preferences. Time and time again these committees with their lofty titles, such as “the Focus Group on Technologies for Network 2030” have been distinguished by their innate ability to see their considered prognostications comprehensively contradicted by reality! Their forebears in similar committees missed computer mainframes, then they failed to see the personal computer revolution, and were then totally surprised by the smartphone.

Enjoy!

Donal O Duibhir was trying to get me to present at INOG for ages, and as much as I’d love to get to Ireland we always had a scheduling conflict.

Last week we finally made it work - unfortunately only in a virtual event, so I got none of the famous Irish beer - and the video about alternate universes of public cloud networking is already online.

Maximilian Wilhelm had great fun turning my usual black-and-white statements into tweets, including:

CloudFlare launched yet another service: transfer speed- and latency measurements done from a web browser. While it’s pretty obvious how you could measure transfer speed (start an asynchronous transfer, register for the JavaScript onreadystatechange event to notice out when it has completed, and compute the transfer rate), measuring latency seems like a bit of black magic. After all, you can’t do a ping from a web browser, can you?

IPv6 is old enough to buy its own beer (in US, not just in Europe), but there are still tons of naysayers explaining how hard it is to deploy. That’s probably true if you’re forced to work with decades-old boxes, or if you handcrafted your environment with a gazillion clicks in a fancy GUI, but if you used Terraform to deploy your application in AWS, it’s as hard as adding a few extra lines in your configuration files.

Nadeem Lughmani did a great job documenting the exact changes needed to get IPv6 working in AWS VPC, including adjusting the IPv6 routing tables, and security groups. Enjoy ;)

On May 14th 2020, Marcel Gamma, tech industry journalist, and editor-in-chief at inside-it.ch and inside-channels.ch, published an article discussing several glaring security vulnerabilities in Silver Peak’s SD-WAN products on inside-it.ch. The original article was written in German; Marcel was kind enough to translate it into English and get permission from his publisher to have the English version published on ipSpace.net.

Security researchers make serious accusations against SD-Wan manufacturer Silver Peak. The latter disagrees. Swiss experts are analyzing the case.

By Marcel Gamma,

Silver Peak is accused of laxity in dealing with security issues and in dealing with security researchers who act within the framework of Responsible Disclosure.

One of the attendees in our Building Network Automation Solutions online course sent me this question:

While building an automation tool using Python for CLI provisioning, is it a good idea to use SDK provided by device vendor, or use simple SSH libraries Netmiko/Paramiko and build all features (like rollback-on-failure, or error handling, or bulk provisioning) yourself.

The golden rule of software development should be “don’t reinvent the wheel”… but then maybe you need tracks to navigate in the mud and all you can get are racing slicks, and it might not make sense to try to force-fit them into your use case, so we’re back to “it depends”.

Loved the article from Philip Laplante about environmental antipatterns. I’ve seen plenty of founderitis and shoeless children in my life, but it was worshipping the golden calf that made me LOL:

In any environment where there is poor vision or leadership, it is often convenient to lay one’s hopes on a technology or a methodology about which little is known, thereby providing a hope for some miracle. Since no one really understands the technology, methodology, or practice, it is difficult to dismiss. This is an environmental antipattern because it is based on a collective suspension of disbelief and greed, which couldn’t be sustained by one or a few individuals embracing the ridiculous.

That paragraph totally describes the belief in the magical powers of long-distance vMotion, SDN (I published a whole book debunking its magical powers), building networks like Google does it, intent-based whatever, machine learning…

Pete Lumbis started his Cumulus Linux 4.0 update with an overview of differences between Cumulus Linux on hardware switches and Cumulus VX, and continued with an in-depth list of ASIC families supported by Cumulus Linux.

You can watch his presentation, as well as the more in-depth overview of Cumulus Linux concepts by Dinesh Dutt, in the recently-updated What Is Cumulus Linux All About video.

It’s amazing how sometimes people fond of sharing their opinions and buzzwords on various social media can’t answer simple questions. Today’s blog post is based on a true story… a “senior network architect” fully engaged in a recent hype cycle couldn’t answer a simple question:

Why exactly would you need VXLAN and EVPN?

We could spend a day (or a week) discussing the nuances of that simple question, but all I have at the moment is a single web page, so here we go…

A few weeks ago I described the basics of AWS networking, now it’s time to describe how different Azure is.

As always, it would be best to watch my Azure Networking webinar to get the details. This blog post is the abridged CliffsNotes version of the webinar (and here’s the reason I won’t write a similar blog post for other public clouds ;).

Here’s the final push before we hit the summer break at the end of June (and recover a bit from the relentless production of new content we had throughout the first half of 2020):

• I finished the Introduction to Containers and Docker update just in time to cover the nuances of Docker Networking before the summer break. The first live session will take place today, the second one on June 11th.
• Later this week (May 28th) we’ll have some fun with routing protocol basics.
• Dinesh Dutt covered Vagrant in his last live session and plans to cover other network simulation tools on June 2nd.
• We did a “should I use VMware NSX or Cisco ACI” webinar a few years ago. In the meantime both vendors launched major new features, so it’s high time for a thorough refresh starting on June 9th.
• Mario Rosi will continue the Cisco ACI Introduction series on June 16th.
• David Barroso described the basics of Nornir in our network automation course. We’ll turn that material into an independent webinar (available with standard ipSpace.net subscription) and David plans to augment it with a deep dive into Nornir internals in a live session on June 18th.
• I will need another live session on June 23rd to continue the NSX-or-ACI comparison, and we plan to start the summer break on June 25th.

Helping a friend of mine figure out the details of using Salt in Zero-Touch-Provisioning environments, Zach Moody sent me a description of their process, and was kind enough to allow me to turn it into a blog post.

We follow the same basic ZTP process you would with anything else. Salt drives the parts that interface with the network devices with information from our source-of-truth, NetBox.

David Varnum created a fantastic leaf-and-spine fabric of vEOS switches running with GNS3 and automated with Ansible playbooks.

Not only that - his blog post includes detailed setup instructions, and the corresponding GitHub repository contains all the source code you need to get it up and running.

After describing Cisco SD-WAN fundamentals and its network abstraction mechanisms, David Penaloza explained the components of Cisco SD-WAN solution and its architecture, including in which plane each element operates and its assigned role in the overlay network.