I managed to get another awesome lineup of guest speakers for the Spring 2017 Building Next-Generation Data Center course (starting in less than a month):

Scott Lowe will open the course with a presentation on the impact of open source software in data center environments.

Have you ever tried to navigate complex data structures within Ansible playbooks using awkward looping constructs and convoluted map filters?

It might be easier to munge the data structure into a more appropriate format first and then use the munged data in subsequent tasks. Wondering how to do it?

One of my readers wondered what the difference between fabric extenders and leaf-and-spine fabrics is:

We are building a new data center for DR and we management is wanting me to put in recommendations to either stick with our current Cisco 7k to 2k ToR FEX solution, or prepare for what seems to be the future of DC in that spine leaf architecture.

Let’s start with “what is leaf-and-spine architecture?”

In the last part of the free Docker Networking Fundamentals webinar Dinesh Dutt described the newer high-performance networking options (Macvlan and Ipvlan) introduced in Docker version 1.12.

When Facebook announced 6-pack (their first chassis switch) my reaction was “meh” (as well as “I would love to hear what Brad Hedlund has to say about it”). When Facebook announced Backpack I mostly ignored the announcement. After all, when one of the cloud-scale unicorns starts talking about their infrastructure, what they tell you is usually low on detail and used primarily as talent attracting tool.

Imagine you were asked to migrate some of the workloads running in your data center into a public (or managed) cloud. These workloads still have to access the data residing in your data center – a typical hybrid cloud deployment.

Next thing you know you have to deal with your (C)ISO and his/her usual concerns as well as the variety of articles on tech sites stating that "security is the biggest challenge of cloud adoption".

I got this tweet after publishing the “use Ansible to execute a single command on all routers” blog post (and a few similar comments on the blog post itself)

Or use Python, Netmiko and a simple For loop

I never cease to be amazed by the urge to do undifferentiated heavy lifting in the IT industry.

One of my readers sent me a list of questions after watching some of my videos, starting with a generic one:

While working self within large corporations for a long time, I am asking myself how it will be possible to move from messy infrastructure we grew over the years to a modern architecture.

Usually by building a parallel infrastructure and eventually retiring the old one, otherwise you’ll end up with layers of kludges. Obviously, the old infrastructure will lurk around for years (I know people who use this approach and currently run three generations of infrastructure).

In 2013, large-scale cloud providers and ISPs decided they had enough of the glacial IETF process of generating YANG models used to describe device configuration and started OpenConfig – a customer-only initiative that quickly created data models covering typical use cases of the founding members (aka “What Does Google Need”).

Angelos Vassiliou sent me an interesting lengthy email after I published my OSPF Forwarding Address series (part 1, part 2, part 3, part 4). I asked him whether it’s OK to publish his email together with my responses as a blog post and he gracefully agreed, so here it is.

Cumulus Linux 3.2 shipped with a rudimentary EVPN implementation and everyone got really excited, including smaller ASIC manufacturers that finally got a control plane for their hardware VTEP functionality.

However, while it’s nice to have EVPN support in Cumulus Linux, the claims of its benefits are sometimes greatly exaggerated.

I was using Ansible playbooks to configure Cisco IOS routers running in VIRL and wanted to extract the router configurations before stopping the simulation.

You can download the playbooks from my Github repository, and here’s how you can run Ansible with VIRL.

The featured webinar in February 2017 is the Network Automation 101 webinar, and the featured video describes the reasons you should be interested in network automation, its basics, and the difference between automation and orchestration.

Running BGP instead of an IGP in your leaf-and-spine fabric sounds interesting (mainly if your fabric is large enough). Configuring a zillion BGP knobs on every box doesn’t.

However, BGP doesn’t have to be complex. In the Simplify BGP Configurations video (part of leaf-and-spine fabric designs webinar) Dinesh Dutt explains how you can make BGP configurations simple and easy-to-understand.

Remember the kludges needed to make OSPF NSSA areas work correctly? We concluded that saga by showing how the rules of RFC 3101 force a poor ASBR to choose an IP address on one of its OSPF-enabled interfaces as a forwarding address to be used in Type-7 LSA.

What could possibly go wrong with such a “simple” concept?