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Roman Dodin#

Roman Dodin

Hey there! I'm Roman Dodin, a member of the SR Linux Product Management team at Nokia. Although I am much more often called a "containerlab guy" as I am one of the maintainers of the project.

Network automation, virtual networking labs and beautifully looking docs with reproducible examples are my passion. I am also a big fan of open source initiatives and community building.


VLANs on SR Linux

Discussions: ·

What was one of the most common questions in our SR Linux discord in 2023?

EVPN? YANG? Streaming Telemetry? Programmability? Scaling DC workloads?

No. VLANs 😅

This buddy hurt you good in your early days, right? With global VLANs, trunks, and forgotten add? Your understanding of VLANs provisioning might get clouded by the industry-standard way of doing things, which may result in a lot of confusion when you start working with SR Linux.

Get yourself comfy, we are about to have a deep dive into VLANs on SR Linux.

cisco-man

SSH Terrapin Attack and Network Operating Systems

Discussions: ·

Terrapin is a prefix truncation attack targeting the SSH protocol. More precisely, Terrapin breaks the integrity of SSH's secure channel.

Pretty scary stuff, innit? Any Network Engineer/Admin understands the importance of SSH in their daily work. It's the most common way to access network devices, and it's the most secure way to do so. Is it now?

On December 18th 2023, a group of researchers from the Ruhr University Bochum publicly disclosed a new attack (CVE-2023-48795: General Protocol Flaw) on SSH protocol, called Terrapin. Targeting the very best SSH Binary Packet Protocol researchers proved that an attacker can remove an arbitrary amount of messages sent by the client or server at the beginning of the secure channel without the client or server noticing it.

But what does it mean to us, Network Engineers? Do we need to rush the vendors patching the SSH servers in their NOSes? Let's figure it out.

Sharing SR Linux Terminal with SSHX

Countless times I've been in a situation where I needed to share my terminal with someone or being asked to connect to someone's device instead.

Either I exhausted my networking foo and needed help from a colleague, or I was the one who was asked to help. In both cases, the problem was the same - how to quickly, securely1 and effortlessly share the terminal with someone else.

The problem is not new and there are many options on the table. From installing a VPN software and sharing the credentials, through zero-trust solutions like teleport, to using a simple SSH tunnel. All of these solutions are great, but they require some setup and configuration. And sometimes you just want to share your terminal with someone without going through the hassle of setting up a VPN or a zero-trust solution.

The sshx.io open-source service that just popped out offers a simple solution to this problem.

  1. Install the multi-arch lightweight2 sshx binary on your machine
  2. Run sshx
  3. Share the URL with someone
  4. Enjoy collaborative terminal in a responsive web UI with a multi panel canvas

I felt an immediate urge to try it out with SR Linux. And it worked like a charm!

Instant SR Linux Labs

Containerlab already made it possible to quickly launch labs on demand with just a few commands. You would need to clone a repository with the lab and then call containerlab deploy to start the lab.

Simple enough, but quite often you want to run this simple SR Linux lab to test something quickly using a very basic topology. At times like this it is cumbersome to find and clone the repository and then call deploy command. Can we make it even more simple? Yes, we can!

SR Linux CLI: Wildcards and Ranges

The SR Linux Command Line Interface (CLI) stands out as one of the most advanced and user-friendly CLI systems I've encountered. It breaks away from the conventional "industry standard" and introduces several innovative concepts that greatly enhance the ease of configuring and managing the network operating system. Among these innovations are "CLI wildcards and ranges," which, once mastered, can significantly improve your overall experience and efficiency.

The idea of using wildcards and ranges is not novel, as some CLI systems already include support for them. Nevertheless, SR Linux takes the concept of ranges and wildcards one step further, and in this post, we will explore how to harness their power effectively.

Exposing Kubernetes Services to SR Linux-based IP Fabric with Anycast Gateway and MetalLB

In the era of applications, it is easy to forget about the underlying infrastructure that interconnects them. However, the network is still the foundation of any application as it provides the connectivity and services that applications rely on.

The most popular container orchestration system - Kubernetes - is no exception to this rule where infrastructure is essential for several reasons:

  1. DC fabric: Almost every k8s cluster leverages a DC fabric underneath to interconnect worker nodes.
  2. Communication Between Services: Kubernetes applications are often composed of multiple microservices that need to communicate with each other. A well-designed network infrastructure ensures reliable and efficient communication between these services, contributing to overall application performance.
  3. Load Balancing: Kubernetes distributes incoming traffic across multiple instances of an application for improved availability and responsiveness. A robust network setup provides load balancing capabilities, preventing overload on specific instances and maintaining a smooth user experience.
  4. Scalability and Resilience: Kubernetes is renowned for scaling applications up or down based on demand. A resilient network infrastructure supports this scalability by efficiently routing traffic and maintaining service availability even during high traffic periods.

Getting familiar with all these features is vital for any network engineer working with a fabric supporting a k8s cluster. Wouldn't it be great to have a way to get into all of this without the need of a physical lab?

In this blog post we will dive into a lab topology that serves as a virtual environment to test the integration of a Kubernetes cluster with an IP fabric. The emulated fabric topology consists of a SR Linux-based Clos fabric with the Kubernetes cluster nodes connected to it. The k8s cluster features a MetalLB load-balancer that unlocks the capability of announcing deployed services to the IP fabric.

Throughout the lab, we will explore the way k8s services are announced to the IP fabric, and how L3 EVPN service with Anycast Gateway can be leveraged to create a simple and efficient overlay network for external users of the k8s services.

As for the tooling used to bring up the lab we will use Minikube to deploy a personal virtual k8s cluster and Containerlab will handle the IP fabric emulation and the connection between both environments.

gNxI Browser - A documentation UI for Openconfig gRPC services

In the past year, there has been a lot of buzz around gRPC and Openconfig services. Network engineers started to hear more g-acronyms: gNMI, gNOI, gRIBI. The bravest ones started to play with them, and those who like to live on the edge even started to use them in production. But the majority of network engineers are still not familiar with these technologies. The lack of tools to explore and understand these new technologies is one of the reasons for this.

You probably know that in srl-labs we strive for quality tools, and we are not afraid to build them ourselves. The famous gnmic, gnoic, gribic by Karim Radhouani are stellar examples of our effort to make gRPC and Openconfig services more accessible to network engineers.

Today we are happy to announce another initiative by our team - gnxi.srlinux.dev - a documentation UI for Openconfig gRPC services. It is a simple web application that allows you to explore Openconfig gRPC services and their protobuf definitions.

We hope that it will help network engineers to get familiar with gRPC and Openconfig services and we wanted to tell you how we built it.

Official Ansible collection for SR Linux

Ever since we released a tutorial that showed how to use Ansible's URI module with SR Linux, we couldn't shake off the feeling that we would need to do more with Ansible. And we did.
We are happy to announce that we have released an official Ansible collection for SR Linux - nokia.srlinux - that has four modules inside and leverages JSON-RPC interface.

In this blog post, we would like to share some details about our design decisions and why we think this collection is a great addition to the Ansible ecosystem.

SR Linux logging with ELK

Join the discussion: LinkedIn post · Twitter thread

In a not-so-distant past, manually extracting, parsing, and reading log files produced by network elements was standard practice for a sysadmin. With arcane piping of old-but-good grep, awk, and sed tools, one could swiftly identify a problem in a relatively large system. This was a viable approach for quite some time, but it became prey to a massive scale.

Today's network infrastructures often count thousands of elements, each emitting log messages. Getting through a log collection of this size with CLI tools designed decades ago might not be the best tactic. As well as correlating logs between network elements and application logs might be impossible without software solutions built with such use cases in mind.

The unprecedented growth in the application world boosted the development of multi-purposed centralized/cloud data collectors that make observability and discovery over huge data sets a reality. Elasticsearch / Logstash / Kibana (or ELK for short) is one of the most known open-source stacks tailored for the collection and processing of various documents, logs included.

To enable the processing of captured logs and deliver performant and robust search analytics log collectors rely on structured data. Unfortunately, the networking world is infamous for iterating slowly. For example, an outdated and informational Syslog interface still dominates the networking space when it comes to managing and transferring logs. Syslog RFC31644 was not designed to allow extensible structured payloads, which adds a fair share of problems with integrating such systems with modern log collectors.

This post explains how an SR Linux-powered DC fabric can be integrated with a modern logging infrastructure based on the Elasticsearch / Logstash / Kibana stack to collect, transform, handle, and view logs.