Idempotence and Declarative Methods - not just buzzwords Idempotence Coined by Benjamin Peirce, this term indicates that a mathematical operation will produce a consistent result, even with repetition. Idempotence is much more complicated subject in mathematics and computer science. IT and DevOps use a simplified …

Read More

Have you seen this selector when building machines on vSphere? This causes some fairly common issues in NOS VMs, as most don't really know what distribution the NOS is based on. "Guest OS Version" doesn't just categorize your workload, though. Selecting "Other Linux" instructs vSphere to maximize …

Read More

DNS is a vital component of all computer networks. Also known as the "Internet Yellow Pages," this service is consumed by every household. DNS services are typically deployed in several patterns to support users and systems: DNS Forwarder: This deployment method is the most common. Everybody needs name …

Read More

TL;DR If you see either of these errors, check grep 'ERROR' /opt/avi/log/cc_agent_go_{{ cloud }} for the potential cause. In my case, the / character was not correctly processed by Avi's Golang client (facing vCenter). The Problem When trying to configure NSX ALB + NSX-T on my home lab, I am presented nothing but the …

Read More

At some point, we can't "do it all" with one block of code. As developers, we need to store persistent data for a variety of reasons: We want it for later execution (or to compare it to another result) We're sick of storing variables in code. This matters a lot more in compiled languages than runtime ones We …

Read More

For this example deployment, I'll be using my NSX-T Lab as the fabric, VyOS for the Overloaded Router role, and trying out hyperglass: Installation (VyOS) I already have a base image for VyOS with its management VRF set up - and updating the base image prior to deployment is a breeze due to the vSphere 7 VM Template …

Read More

It's probably safe to say that service provider networking is pretty unique. One particular design pattern - Looking Glasses - is extremely useful for complex dynamically routed networks. I'd really like to shift the gatekeeping needle here - networks that are complex enough to benefit from a looking glass should move …

Read More

After all that meatspace talk, let's look at a few technical solutions and why they might not meet business needs in a specific setting. Shared Control Planes / Shared Failure Plane Shared Control Plane design patterns are prolific within the networking industry - and there's a continuum. Generally, a control plane …

Read More

We don't always earn reliability with the systems we deploy, design, and maintain Infrastructure reliability is a pretty prickly subject for the community - we as engineers and designers tend to anthropomorphize, attach, and associate personal convictions with what we maintain. It's a natural pattern, but it inflicts a …

Read More

NGINX Rewrite Directives, The 9/10 Solutions When doing ADC/Load Balancer work, nearly all requests fit into two categories: Please rewrite part of the URL/URI Please change the host header for this reverse proxy These are fairly simple to implement in NGINX, so I'm creating a couple of cheat-sheet code snippets here. …

Read More