I was discussing a totally unrelated topic with Terry Slattery when he mentioned a quote from the Mythical Man-Month. It got me curious, I started exploring and found out I can get the book as part of my Safari subscription.

From the moment Cisco and VMware announced VXLAN some networking engineers complained that they'd lose visibility into the end-to-end path. It took a long while, but finally the troubleshooting tools started appearing in VXLAN environment: NVO3 working group defined Fault Managemnet framework for overlay networks and Cisco implemented at least parts of it in recent Nexus OS releases.

You'll find more details in Software Gone Wild Episode 69 recorded with Lukas Krattiger in November 2016 (you can also watch VXLAN Technical Deep Dive webinar to learn more about VXLAN).

Ansible is great at capturing and using JSON-formatted data returned by REST API (or any other script or method it can invoke), but unfortunately some of us still have to deal with network devices that cannot even spell structured data or REST.

The featured webinar in January 2017 is the Introduction to Docker webinar, and in the featured video Matt Oswalt explains the basic Docker tasks. Other videos in this webinar cover Docker images, volumes, networking, and Docker Compose and Swarm.

To view the featured video, log into my.ipspace.net, select the webinar from the first page, and watch the video marked with star.

One of my subscribers sent me this question after watching the second part of Network Automation Tools webinar (or maybe it was Elisa Jasinska's presentation in the Data Center course):

Elisa mentions that for a given piece of data, there should be “one source of truth”. It gets a bit muddled when you have an IPAM tool and Git source control simultaneously. It is not hard to imagine scenarios where these get out of sync especially if you consider multi-operator scenarios.

Confused? He provided a simple scenario:

With January 6th the Christmas/New Year holidays are over even for most European countries, so it’s time to restart my blog and set some goals for 2017.

Webinars

2015 was year of SDN, 2016 was year of network automation, and 2017 is shaping up to be the year of the cloud.

Here’s a trick question:

• Imagine you have a network running IPv4 and VPNv4 services;
• You want to use neighbor next-hop-self on IPv4 sessions, but not on VPNv4 sessions;

To implement this request you use the following configuration commands (plenty of other commands removed because they don’t impact the results):

router bgp 64500
 address-family ipv4
  maximum-paths ibgp 32
  maximum-paths 32
  neighbor 192.168.0.4 next-hop-self
  neighbor 192.168.0.1 next-hop-self
 address-family vpnv4
  maximum-paths ibgp 32
  maximum-paths 32
  no neighbor 192.168.0.4 next-hop-self
  no neighbor 192.168.0.1 next-hop-self

Try to figure out what the end-result will be without connecting to a router or reading the rest of this blog post.

If you're a networking engineer, sysadmin, or NetDevOps guru preferring the power of CLI over carpal-syndrome-inducing GUI you might like the My Looking Glass tool developed by Mehrdad Arshad Rad. Haven't tried it out, but the intro on GitHub page looks promising.

If you decide to try it out (or already did) please share your experience in a comment. Thank you!

As I was trying to automate configuration deployment in a multi-router Cisco IOS lab, I got to a point where the only way of figuring out what was going on was to log commands on Cisco IOS devices. Not a big deal, but I hate logging into a dozen boxes and configuring the same few lines on all of them (or removing them afterwards).

Time for another playbook: this one can push one of many (configurable) configuration snippets to a group of Cisco IOS devices defined in an Ansible inventory file.

Over a month ago I decided to create a lab network to figure out how to solve an interesting Inter-AS MPLS/VPN routing challenge. Instead of configuring half a dozen routers I decided to develop a fully-automated deployment because it will make my life easier.

I finally got to a point where OSPF, LDP, BGP (IPv4 and VPNv4) and MPLS/VPN configurations are created, deployed and verified automatically.