Using NetBox as a Dynamic Inventory Source for Nornir

Using NetBox as a Dynamic Inventory Source for Nornir

If you have used Nornir before, you already know that the most common way to define your inventory is through YAML files. You list your hosts, groups, and defaults in separate files, and Nornir reads them at runtime. This works fine for small labs or quick scripts, but as your network grows, maintaining those files by hand becomes a problem. Every time you add a device, change an IP, or update a site, you have to remember to update your inventory files as well. It is easy to get out of sync.

This is where a source of truth tool like NetBox can help. NetBox is an open source network source of truth. It is a place to document your devices, IP addresses, sites, roles and pretty much anything about your network. Instead of maintaining a separate YAML inventory alongside NetBox, you can pull your inventory directly from NetBox at runtime. That way, Nornir always works with up to date data, and you only have to manage one source of truth.

In this post, we will cover how to use NetBox as a dynamic inventory source for Nornir using the nornir_netbox plugin. If you are new to Nornir, we have Continue reading

Worth Reading 051526


Given the trend of using generative AI tools like ChatGPT, Gemini, Copilot, and Claude for software development, many companies have decided that developers must use GenAI to succeed. I strongly disagree.

 


Here, through a series of randomized controlled trials on human-AI interactions (N = 1,222), we provide causal evidence for two key consequences of AI assistance: reduced persistence and impairment of unassisted performance. Across a variety of tasks, including mathematical reasoning and reading comprehension, we find that although AI assistance improves performance in the short-term, people perform significantly worse without AI and are more likely to give up.

 


Last month, market research company, Gartner, said that AI companies need close to “$2 trillion per year in revenue by 2029”, token consumption of between 50,000 and 100,000 times its current rate by 2030, and “a 10% profit margin per token.” With huge losses and small revenues, it is not likely that AI companies will achieve these goals on time.

 


He said that about 20% of all network traffic today, about 80 exabytes, comes from machine-to-machine traffic, and that alone is big news. Nokia is betting its future growth will come from meeting this growing demand.

 


For Continue reading

Lab: EVPN Asymmetric IRB with Anycast Gateways

I postponed the discussion of ARP issues with EVPN anycast gateways to keep yesterday’s blog post reasonably short. If you’re impatient and want to try that out, I have just the right lab exercise for you; you’ll have to extend VLANs into end-to-end MAC-VRF instances and add IRB and anycast gateways:

Explore the lab exercise

You can run the lab on your own netlab-enabled infrastructure (more details), but also within a free GitHub Codespace or even on your Apple-silicon Mac (installation, using Arista cEOS container, using VXLAN/EVPN labs).

Cisco AUTOCOR Passed

Yesterday I took and passed the Cisco AUTOCOR (previously DEVCOR) exam which is the core exam for CCNP Automation. That means I need a specialist exam to become CCNP Automation certified. It also means I’m qualified to sit the CCIE Automation lab.

What did I think of the exam?

As with any exam, there is good and bad. I’ll start with the good.

The exam aligned well with the blueprint. I didn’t feel there were any real surprises or questions on items that weren’t part of the blueprint.

There wasn’t a lot of trivia. No memorization of specific API endpoints or anything like that.

The exam experience was fine. I took it in a testing facility, which I prefer, and I had no issues. I was provided with earplugs which was nice to stay focused although this is a small facility and there was only one other candidate.

I liked the different types of questions. You have your standard multiple choice, single answer and multiple choice, multiple answer, but also fill in the blanks, and lablets. It’s nice that there is quite a bit of code in the exam, it is an automation exam after all. I also think it’s Continue reading

KubeVirt Live Migration Done Right: What it Takes to Run VMs on Kubernetes

Running VMs in Kubernetes sounds like a crazy workaround for avoiding vendor lock-in, and standardizing legacy applications and newer containerized workloads on one control plane with one set of security policies to govern them all. It is, however, a rapidly growing pattern, and KubeVirt live migration — moving running VMs between nodes without downtime — is increasingly central to platform engineering use cases that require full VMs, like on-demand CI/CD pipelines.

KubeVirt is gaining traction as a way to bring VMs into Kubernetes as first-class workloads, managed with the same tools and primitives that platform teams already use for containers. It has, however, introduced some unique challenges.

Here’s the uncomfortable truth about that migration: compute and storage are the easy parts. Networking is where migrations stall, roadblock multiple, and platform teams start questioning whether KubeVirt was the right call in the first place.

If your VMs have no fixed IP dependencies, no VLAN memberships, and no upstream firewall rules scoped to specific subnets, you can migrate them into Kubernetes without losing sleep over the networking layer. If you’re running hundreds or thousands of VMs with IP addresses hardcoded into application configs, DNS entries, and firewall ACLs — and you need Continue reading

The AI Agent Accountability Crisis: Why Governance Isn’t Keeping Up With Deployment

Every enterprise is building AI agents. Marketing has one summarizing campaign performance. Engineering has one triaging incidents. Customer support has one resolving tickets. Finance has one processing invoices. Each was built by a different team, using a different framework, with different assumptions about security.

Now those agents are talking to each other through agent-to-agent (A2A) communication. The incident-triage agent calls the customer-support agent to check affected accounts. The invoice agent calls an external payment API. The marketing agent queries a data warehouse with customer records.

When something goes wrong (and at this scale of deployment, it will), can you answer:

  • Who authorized the action?
  • What policy permitted it?
  • What was the full chain of events?

If you can’t, you have an accountability gap.

This is part one of a five-part series on AI agent accountability for engineering and security leaders. We’ll work through the gap between agent deployment and governance, the diagnostic framework that exposes it, why your existing tools won’t close it, and the principles you’ll need to evaluate any solution that claims it can.

What is AI agent accountability?

AI agent accountability is the ability to trace, prove, and audit every action an AI agent takes. This includes Continue reading

N4N055: A Wired NAC Walkthrough

Today’s topic is Network Access Control (NAC) for a wired network. To help walk us through it all is Jennifer “JJ” Jabbusch, a network security architect, public speaker, book author, and co-host of the Packet Protector podcast. JJ and our hosts break down the terms and protocols behind NAC, and explain why the architecture was... Read more »

Our billing pipeline was suddenly slow. The culprit was a hidden bottleneck in ClickHouse

At Cloudflare, we are heavy users of ClickHouse, an open-source analytical database management system. We redesigned one of our largest ClickHouse tables to add a column to the partitioning key. The change enabled per-tenant retention on a table that serves hundreds of internal teams. The design went through several rounds of revision and review with engineers across multiple teams before we landed on the final approach. But a few weeks after rollout, the jobs that produce most of Cloudflare's bills were running up against their hard daily deadline.

All the usual suspects looked clean: I/O, memory, rows scanned, parts read. Everything we would normally check when a ClickHouse query is slow appeared to be normal. The problem turned out to be lock contention in query planning, something we'd never had reason to look for before.

This is the story of how this migration exposed a hidden bottleneck in ClickHouse's internals, and the patches we wrote to fix it.

The setup: a petabyte-scale analytics platform

We use ClickHouse to store over a hundred petabytes of data across a few dozen clusters. To simplify onboarding for our many internal teams, we built a system called "Ready-Analytics" in early 2022.

The premise is Continue reading

ARP with EVPN Asymmetric IRB

In a previous blog post, I described the ARP issues you’ll encounter when using centralized routing (on a spine switch) between two EVPN MAC-VRF instances (a fancy name for a VLAN encapsulated in VXLAN or MPLS).

That blog post established a baseline that will help us unravel the ARP behavior in a more realistic scenario: asymmetric Integrated Routing and Bridging (IRB). That’s a mouthful, but it’s really quite a simple concept; the following diagram explains the asymmetric forwarding behavior:

Packet forwarding in an EVPN asymmetric IRB design

Packet forwarding in an EVPN asymmetric IRB design

Read more …

What’s New in Calico v3.32

We’re excited to announce the release of Calico Open Source v3.32! 🎉

This release corresponds with Kubernetes v1.36 (Codename Haru) and it goes beyond just sharing a cat as the mascot of the release, it actually extends capabilities and features of Kubernetes to keep you up to date with the latest innovations of the cloud.

This release brings some of the most significant architectural changes in Calico, from live-migrating KubeVirt VMs to eBPF based Maglev load balancer.
Here’s a quick look at everything that’s new:

🚨 Breaking Changes & Deprecations

  • ClusterNetworkPolicy (Alpha2) replaces Admin and Baseline Admin Network Policies: AdminNetworkPolicy and BaselineAdminNetworkPolicy have been removed. You must migrate to ClusterNetworkPolicy before upgrading to v3.32, as Calico will no longer enforce the old resources.
  • calico-apiserver Deprecated: The aggregated API server is deprecated and will be removed in a future release. It is being replaced by Native v3 CRDs. (Requires MutatingAdmissionPolicy feature gate, Kubernetes 1.30+).

🚀 Key Feature Updates

1. KubeVirt VM Live Migration Support

  • What it does: Allows live-migrating KubeVirt VMs between nodes without dropping TCP connections.
  • How it works: Achieves IP persistence by binding the IP to the VM name rather than the ephemeral pod.
  • Activation: Set kubeVirtVMAddressPersistence: Enabled Continue reading

OpenClaw Ruined AI and It Makes Me Happy

The biggest AI story of 2026 isn’t the growing need for electrical power or the ridiculous way the market sold out for RAM based on a letter of intent to acquire. No, the biggest AI story of the year so far is how a scrappy little project completely upset the AI apple cart. OpenClaw (nee ClaudeBot, nee OpenMolt) set the world on fire. And it destroyed how people were trying to direct AI. I’m sitting over here giggling about it.

Round The Clock

The basics of OpenClaw are simple enough. You have a system of agents that do things. It can read your texts or email and triage the flow of information. It can send you a text summary of the news or the weather every morning. But it can also be configured to monitor things as they arrive to deal with them on the fly. That’s where the real narrative shift has happened.

When you open a browser window to talk to an LLM you are creating a session that has a finite time limit. You are saying that you are going to work on a project for a specific period of time and that’s that. Once you complete Continue reading

NAN122: From Anxiety to Empowerment: Building Confidence into Machine‑Speed Network Updates (Sponsored)

Network teams are being asked to move faster than ever as automation and AI-driven workflows increase the volume and frequency of network changes. In this episode, sponsored by Cisco, we explore how modern network operating systems make zero-downtime, zero-stress updates possible, even at machine speed. We’ll break down three key capabilities: Atomic Config Replace (ACR),... Read more »

Browser Run: now running on Cloudflare Containers, it’s faster and more scalable

We’ve enabled higher usage limits, faster performance, and better reliability for Browser Run by rebuilding on top of Cloudflare’s Containers.

You can now spin up 60 browsers per minute via the Workers binding and run up to 120 concurrently — 4x the previous limit. Also, Quick Action response times dropped more than 50%. You don't need to change anything: these improvements are live today. On top of that, we’re shipping fixes and new features faster than before. Read on to learn how we did it and see the data.

Remind me: what is Browser Run?

Browser Run enables developers to programmatically control and interact with headless browser instances running on Cloudflare’s global network. That’s useful for end-to-end testing of web applications, securely investigating suspicious URLs, and leveraging how browsers can easily render PDF documents, amongst other quick actions like capturing screenshots and extracting content. More recently, it’s become a critical enabler of AI agents to interact with the web. We’re building Browser Run to be the go-to platform to responsibly utilize automated browsers securely at massive scale.

Outgrowing our bunk bed

Before adopting Cloudflare Containers, we shared infrastructure with Browser Isolation (BISO). While technically similar, BISO’s larger container images slowed Continue reading

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