Ivan Pepelnjak

Author Archives: Ivan Pepelnjak

Moving Complexity to Application Layer?

One of my readers sent me this question:

One thing that I notice is you mentioned moving the complexity to the upper layer. I was wondering why browsers don't support multiple IP addresses for a single site – when a browser receives more than one IP address in a DNS response, it could try to perform TCP SYN to the first address, and if it fails it will move to the other address. This way we don't need an anycast solution for DR site.

Of course I pointed out an old blog post ;), and we all know that Happy Eyeballs work this way.

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First Speakers in the Spring 2018 Automation Online Course

For the first two sessions of the Building Network Automation Solutions online course I got awesome guest speakers, and it seems we’ll have another fantastic lineup in the Spring 2018 course:

Most network automation solutions focus on device configuration based on user request – service creation or change of data model describing the network. Another very important but often ignored aspect is automatic response to external events, and that’s what David Gee will describe in his presentation.

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New Content: Debugging Ansible Playbooks and Jinja2 Templates

Here’s a quote from one of my friends who spent years working with Ansible playbooks:

Debugging Ansible is one of the most terrible experiences one can endure…

It’s not THAT bad, particularly if you have a good debugging toolbox. I described mine in the Debugging Ansible Playbooks part of the Ansible for Networking Engineers online course.

Please note that the Building Network Automation Solutions online course includes all material from the Ansible online course.

Automate Remote Site Hardware Refresh Process

Every time we finish the Building Network Automation Solutions online course I ask the attendees to share their success stories with me. Stan Strijakov was quick to reply:

I have yet to complete the rest of the course and assignments, but the whole package was a tremendous help for me to get our Ansible running. We now deploy whole WAN sites within an hour.

Of course I wanted to know more and he sent me a detailed description of what they’re doing:

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Simplifying ipSpace.net Products

When I started my ipSpace.net project life was simple: I had a few webinars, and you could register for the live sessions. After a while I started adding recordings, subscriptions, bundles, roadmaps (and tracks), books… and a few years later workshops and online courses.

As you can imagine, the whole thing became a hard-to-navigate mess. Right now you can buy almost 70 different products on ipSpace.net. Time for a cleanup.

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How Did NETCONF Start on Software Gone Wild

A long while ago Marcel Wiget sent me an interesting email along the lines “I think you should do a Software Gone Wild podcast with Phil Shafer, the granddaddy of NETCONF

Not surprisingly, as we started discovering the history behind NETCONF we quickly figured out that all the API and automation hype being touted these days is nothing new – some engineers have been doing that stuff for almost 20 years.

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BGP as a Better IGP? When and Where?

A while ago I helped a large enterprise redesign their data center fabric. They did a wonderful job optimizing their infrastructure, so all they really needed were two switches in each location.

Some vendors couldn’t fathom that. One of them proposed to build a “future-proof” (and twice as expensive) leaf-and-spine fabric with two leaves and two spines. On top of that they proposed to use EBGP as the only routing protocol because draft-lapukhov-bgp-routing-large-dc – a clear case of missing the customer needs.

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It’s Bash Scripts All the Way Down (more on CLI versus API)

Netfortius made an interesting comment to my Ansible playbook as a bash script blog post:

Ivan - aren't we now moving the "CLI"[-like] approach, upstream (the one we are just trying to depart, via the more structured and robust approach of RESTAPI).

As I explained several times, I don’t know where the we must get rid of CLI ideas are coming from; the CLI is root of all evil mantra is just hype generated by startups selling alternative approaches (the best part: one of them was actually demonstrating their product using CLI).

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