Blog Posts in November 2018
I’m not the only one ranting about the need to get a firm grasp on fundamentals before doing the sexy stuff. Found an old blog post by Joel Spolsky (of the Law of Leaky Abstractions fame) on the exact same topic from programming perspective.
If you ever had to deal with a programming language, it’s definitely worth reading… but some of the details might make your head explode. You’ve been warned ;)
Christoph Jaggi asked me a few questions about using VXLAN with EVPN to build data center fabrics and data center interconnects (including active/active data centers). The German version was published on Inside-IT, here’s the English version.
He started with an obvious one:
What is an active-active data center and why would I want to use an active-active data center?
Numerous organizations have multiple data centers for load sharing or disaster recovery purposes. They could use one of their data centers and have the other(s) as warm or cold standby (active/backup setup) or use all data centers at the same time (active/active).
December will start with three on-site events:
- We’ll run Using VXLAN and EVPN to Build Active-Active Data Centers workshop in Zurich on December 5th;
- I’ll talk about making SDN better with IPv6 on December 6th;
- Next day (December 7th) I’ll talk about Real-life SDN in Rapperswil (a lovely medieval town at the tip of Lake Zurich).
On the webinar front, December will be a storage month:
A friend of mine told me about a “VXLAN is insecure, the sky is falling” presentation from RIPE-77 which claims that you can (under certain circumstances) inject packets into VXLAN virtual networks from the Internet.
Welcome back, Captain Obvious. Anyone looking at the VXLAN packet could immediately figure out that there’s no security in VXLAN. I pointed that out several times in my blog posts and presentations, including Cloud Computing Networking (EuroNOG, September 2011) and NSX Architecture webinar (August 2013).
You highlight the hygiene of automation. What is it and why does it matter?
Hygiene is the important but boring bit of automation most beginners and amateurs pass by.
After a series of forward-looking podcast episodes we returned to real life and talked with Carl Buchmann about his network automation journey, from managing upgrades with Excel and using Excel as the configuration consistency tool to network-infrastructure-as-code concepts he described in a guest blog post in February 2018
Some (anti)patterns of network industry are way too predictable: every time there’s a new technology marketers start promoting it as the solution for every problem ever imagined. VXLAN was quickly touted as the solution for long-distance vMotion, and now everyone is telling you how to use VXLAN with EVPN to stretch VLANs across multiple data centers.
Does that make sense? It might… based on your requirements and features available on the devices you use to implement the VXLAN/EVPN fabric. We’ll cover the details in a day-long workshop in Zurich (Switzerland) on December 5th. There are still a few places left, register here.
David Gee is coming back to Building Network Automation Solutions online course – in early March 2019 he’ll talk about hygiene of network automation. Christoph Jaggi did an interview with him to learn more about the details of his talk, and they quickly diverted into an interesting area: automated workflows.
Automation is about automated workflows. What kind of workflows can be automated in IT and networking?
Workflows most often fall into categorizations of build, operations and remediation.
Here’s another interesting talk from RIPE77: Routing Attacks in Cryptocurrencies explaining how BGP hijacks can impact cryptocurrencies.
TL&DR: Bitcoin is not nearly decentralized enough to be resistant to simple and relatively easy BGP manipulations.
You know that time of year when snowflakes mean more than description of uniqueness of your networking infrastructure? Some people love to complain about that season and how the weather hinders them, others put on sturdy winter boots and down jackets, change tires on their car, and have tons of fun.
Network automation is no different. Sometimes you can persuade your peers that it makes sense to simplify and standardize the infrastructure to make it easier to abstract and automate (consider that an equivalent of going to a tropic island with shiny beaches and everlasting summer), other times you have to take out your winter boots and make the best out of what you got.
In spring 2018 I started collecting real-life automation wins reported by the attendees of my Building Network Automation Solutions online course. I presented them at Troopers, and as a set of network automation use cases that are available to all ipSpace.net subscribers, some of them even with free subscription.
Today let’s start with how did it start story.
One of my readers sent me this question:
It would be nice to have a blog post or a webinar describing how to implement container networking in case when: (A) application does not tolerate NAT (telco, e.g. due to SCTP), (B) no DNS / FQDN, is used to find the peer element and (C) bandwidth requirements may be tough.
A lightning talk at the recent RIPE77 conference focused on shortcomings of VXLAN and rise of Geneve.
So what are those perceived shortcomings?
No protocol identifier – a single VXLAN VNI cannot carry more than one payload type. Let me point out that MPLS has the same shortcoming, as does IPsec.
This blog post was initially sent to subscribers of my SDN and Network Automation mailing list. Subscribe here.
The “everyone should be a programmer” crowd did a really good job of scaring network engineers (congratulations, just what we need!). Here’s a typical question I’m getting:
Do I need to be good in scripting to attend your automation course.
TL&DR: Absolutely not.
Here’s a question I got from someone attending the Building Next-Generation Data Center online course:
Cisco NCS5000 is positioned as a building block for a data center MPLS fabric – a leaf-and-spine fabric with MPLS and EVPN control plane. This raised a question regarding MPLS vs VXLAN: why would one choose to build an MPLS-based fabric instead of a VXLAN-based one assuming hardware costs are similar?
There’s a fundamental difference between MPLS- and VXLAN-based transport: the amount of coupling between edge and core devices.
The last two months of 2018 will be jam-packed with webinars and on-site events:
- Dinesh Dutt will talk about network observability, how it’s different from monitoring and why it matters on November 8th;
- I’ll continue the Amazon Web Services networking saga with the third live session on November 15th. We already covered VPCs, interfaces and addresses, network security, route tables, and Internet connectivity. Now it’s time for VPNs, Direct Connect and VPC peering;
- The annual Data Center Fabric Architectures update will take place on November 22nd. I’ll cover the changes in data center switching market, and new hardware launched by major vendors;
- The Network Connectivity and Graph Theory webinar was a huge hit, so we agreed with Rachel Traylor to do a whole series of similar webinars. On November 29th she’ll cover Reliability Theory: Networking through a Systems Analysis Lens;
December will be a storage, EVPN and SDN month:
Yves Haemmerli, Consulting IT Architect at IBM Switzerland, sent me a thoughtful response to my we need product documentation rant. Hope you’ll enjoy it as much as I did.
Yes, whatever the project is, the real added value of an IT/network architect consultant is definitely his/her ability to create models (sometimes meta-models) of what exists, and what the customer is really looking for.
I long while ago I stumbled upon an excellent resource describing why distributed systems are hard (what I happened to be claiming years ago when OpenFlow was at the peak of the hype cycle ;)… lost it and found it again a few weeks ago.
If you want to understand why networking is hard (apart from the obvious MacGyver reasons) read it several times; here are just a few points: