brvirt: when brctl meets virsh


Hypervisors diversity is definitely one of the benefits of having Nuage managing your next-generation network. That means that we, as Nuage engineers, have to play with all kinds of hypervisors — like KVM, ESXi and Hyper-V to be more precise. As to me, I love to work with KVM most, simply because it gives you that feel that you are in control and can fine-tune or troubleshoot with granularity you want. Thanks to opensource tools like tcpdump, virsh, ss, top, brctl and many many others!

But these tools won’t fit perfectly for every situation every time. For example consider a simple case of a Linux host with a bunch of VMs connected via Linux bridges and answer a simple question: how to determine what VM names correspond to what virtual network interfaces connected to what bridges? I have to say that this question arises quite often when you troubleshoot network connectivity between VMs or gathering network stats.

And the answer to this question can not be provided with above mentioned tools without some scripting. Indeed, in this post I will share a script called brvirt which does the job by combining iproute2 and virsh outputs.

Link: Github repo.


Using free Yandex DNS service in an automated way


This DNS story started when I bought a domain with a specific need — to dynamically create and delete DNS records for Nuage Networks components we use during Proof Of Concepts and customers trials.

Earlier I used to rely on Dynamic DNS services (i.e. whenever I needed a DNS name for my public endpoints. But this approach has two drawbacks:

  1. To use if for free you have to manually prolong you hostname once in a month. Drove me mad every time!
  2. In PoCs/trials you want your domain represent your product. Using in front of a customer is not something that speaks well for your product. And we all know that devil is in the details.

Therefore I decided to buy a domain that will represent a product we are offering and park it to some provider which offers robustfree and API-enabled DNS service. Google cloud DNS and DynDNS while being both cheap are not free. So I kept looking and ended up with Yandex DNS which has all three traits I was looking for. Lastly I automated this DNS workflow so everyone in my team could provision their own DNS entries via one shared tool.

You got it right, in this post I am going to tell you about a completely free DNS service from Yandex with a decent API you can use for your personal needs. And yes, this post is accompanied with a python script which leverages API and automates DNS records provisioning.


LSA issue @ December 13, 2016 at 10:24AM

Here is your fresh IPv6 fix: Tenth iNOG, namely iNOG::A, is all about IPv6 experience.
Technical talks are:
1) Orla McGann (HEAnet) An Irish IPv6 Fairytale
2) Nathalie Trenaman (RIPE) The Sad Tale of 462 Operators Who Switched Off IPv6* (*with a happy ending)
3) Ed Horley (Groupware Technology) IPv6 Operating Challenges

Particulary interesting talk was given by Nathalie from RIPE who was talking about IPv6 global perception seen from RIPE point-of-view.

#Video #iNOG #IPv6
By: via LSA


LSA issue #December 9, 2016 at 02:27PM

There is a popular saying that you don't need to be a programmer to automate your network. Might be true, though you definitely won't succeed in automation tasks without basic Regular Expressions knowledge, that you should take for granted.
Sad thing that regular expressions are not an easy nut to crack, and with this post we would like to share with you useful resources that will help you meet and greet RegExps!

#TipsTricks #Programming — Mastering Regular Expressions, 3rd Edition. — a free and massive tutorial on RegExps — regexps collection for different tasks — the best online regexp engine to test and validate your regexps — solving regexps just for fun — book a place on your desk to hang this RE cheatsheet
By: via LSA