Multi-Machine Vagrant with YAML

In this post, I’ll describe a technique I found for simplifying the use of multi-machine Vagrantfiles by extracting configuration data into a separate YAML file. This technique is by no means something that I invented or created, so I can’t take any credit whatsoever; this is an idea I first saw here. I wanted to share it here in the hopes that it might prove useful to a larger audience.

If you aren’t familiar with Vagrant and Vagrantfiles, you might start with my quick introduction to Vagrant.

I found this technique after trying to find a way to simplify the creation of multiple machines using Vagrant. Specifically, I was trying to create multiple instances of CoreOS along with an Ubuntu instance for testing things like etcd, fleet, Docker, etc. The Vagrantfile was getting more and more complex, and making changes (to add another CoreOS node, for example) wasn’t as straightforward as I would have liked.

So what’s the fix? As with other DSLs (domain-specific languages) such as Puppet, the fix was found in separating the data from the code. In Puppet, that means parameterizing the module or class, and I needed to use a similar technique here with Vagrant. So, Continue reading

All You Need Are Two Top-of-Rack Switches

Every time I’m running a classroom version of my Designing the Cloud Infrastructure workshop, I start with a simple question: “Who has more than 2000 VMs or bare-metal servers in the data center?”

I might see three hands on a good day; 90-95% of the audience have smaller data centers… and some of them get disappointed when I tell them they don’t need more than two ToR switches in their data center.

Read more ...

Vulnerable OMA-DM Implementations and Over the Air Hacks

Earlier today, I was listening to Risky Business show #341. In this show Matt Solnik discussed vulnerabilities that he attempted to share at BlackHat. I say attempted, because it sounds like they may have had some issues with audio/video during critical times of the presentation. Nonetheless, it seems like there are many vulnerable implementations of the open mobile administration device management (OMA-DM). I took a minute to dig up some of the videos published by Accuvant that makes this stuff real.

Over the Air Code Execution and Jailbreak

NIA-Based Lock Screen Bypass

External Links

Disclaimer: This article includes the independent thoughts, opinions, commentary or technical detail of Paul Stewart. This may or may not reflect the position of past, present or future employers.

Readers of this article may also enjoy:

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  3. Pluribus Networks at Networking Field Day 7
  4. Dell at Networking Field Day 7
  5. Y.M.C.A er O.S.P.V

The post Vulnerable OMA-DM Implementations and Over the Air Hacks appeared first on PacketU.

Response: HowTo Configure IP Multicast PIM on ECMP| Mellanox Interconnect Community


Today I spent several hours reading up on PIM Bidirectional for an customer implementation on an ECMP networking. I realise that somewhere inside my head there is a lot of IP Multicast knowledge that hasn’t been lost but it is definitely hiding. I had to re-learn a number of concepts before I started feel confident. […]

The post Response: HowTo Configure IP Multicast PIM on ECMP| Mellanox Interconnect Community appeared first on EtherealMind.

The Ultimate Portable Laptop Stand – Rooststand !!

Original content from Roger's CCIE Blog Tracking the journey towards getting the ultimate Cisco Certification. The Routing & Switching Lab Exam
I was looking for a portable laptop stand as I have been starting to get neck pain hunched over my laptop all day. Working at home, in the office and on client sites I needed a laptop stand and it had to be portable. I searched the internet for portable laptop stands and apart from... [Read More]

Other pages of interest:

Post taken from CCIE Blog

Original post The Ultimate Portable Laptop Stand – Rooststand !!

Twitter, Please Stop Giving Me Things I Don’t Want

new-twitter-logo

Last week, Twitter confirmed that they will start injecting tweets from users you don’t follow into your timeline.  The collective cry from their user base ranged from outrage to a solid “meh”.  It seems that Twitter has stumbled onto the magic formula that Facebook has perfected: create a feature the users don’t care about and force it onto them.  Why?

Twitter Doesn’t Care About Power Users

Twitter has an interesting mix of users.  They reported earlier this year that 44% of their user base has never tweeted.  That’s a lot of accounts that were created for the purpose of reserving a name or following people in read-only mode.  That must concern Twitter.  Because people that don’t tweet can’t be measure for things like advertising.  They won’t push the message of a sponsored tweet.  They won’t add their voice to the din.  But what about those users that tweet regularly?

Power users are those that tweet frequently without a large follower base.  Essentially, everyone that isn’t a celebrity with a million followers or a non-tweeting account.  You know, the real users on Twitter.  The people that make typos in their tweets and actually check to see who follows them.  The ones Continue reading

Software-Defined Data Center Straight Talk with Tom Burns & JR Rivers

The data center is flush with change and it’s hard to know where to turn for advice. The myriad vendor positions on technology are confusing and seem self-motivated to lock you into their technology. Meanwhile, your data center is being flooded with more traffic every day.

Getting advice is hard so it’s not every day you get to talk with two of the world’s foremost thinkers in the data center world. With Tom Burns (Vice President and General Manager, Dell Networking and Enterprise Infrastructure) and JR Rivers (Co-founder/CEO of Cumulus Networks) joining me, I will get that special privilege on November 20 when I host a webinar to discuss open networking in the software-defined data center (SDDC).

Yeah, I know what you’re thinking. Another webinar with a bunch of marketing buzzwords. Well, if you know these guys you know that won’t be the case. I’ll moderate the discussion by teeing up a few questions and getting out of their way.

We’re planning to discuss a number of topics that will be sure to provoke some strategic thinking on your part. We’ll discuss:

  • Major data center challenges and how best to address them,
  • The current state of enterprise-ready SDDC technologies and Continue reading

Secrets Behind A10 Health Monitors

Whether you use A10, f5 or some other load balancer, you’re probably used to the idea of health monitors, or “health checks”. The load balancer periodically performs some kind of connectivity test to the servers that are used to service … Continue reading →

If you liked this post, please do click through to the source at Secrets Behind A10 Health Monitors and give me a share/like. Thank you!

Outcome bias and the psychology that prevents sustained success

In psychology, there is a phenomenon called Outcome Bias, which basically means that we tend to judge the efficacy of a decision based primarily on how things turn out. After a decision is made, we rarely examine the conditions that existed at the time of the decision, choosing instead to evaluate performance based solely (or mostly) on whether the end result was positive or not.

But what happens as luck plays a role in outcomes? Did we actually make the best decision? Or was the result really a product of conditions outside of our control?

Understanding Outcome Bias

A relatively strong example of Outcome Bias can be found in the gambling world. Take poker, for instance. Many players will overplay the cards they are dealt. Imagine that you have four cards to a straight. There are two remaining cards to play. You might make bets that are statistically weak, but if the card you were looking for shows up, you will evaluate your own performance as strong for the hand. After all, you did win, right?

The challenge with Outcome Bias is that the fortuitous turn of events leads you play other hands in a similar way. Despite the fact Continue reading

First Impressions of the OpenDaylight Helium Release

First Impressions of the OpenDaylight Helium Release

by Hariharan Ananthakrishnan, Distinguished Engineer - October 21, 2014

OpenDaylight introduced Helium last month, which is a major upgrade to its open source SDN controller. Here’s my take on its features, shortcomings and strengths from an engineering perspective. 

Helium is the second software release from the OpenDaylight project and includes the following notable enhancements and new features: 

  1. Support for the Apache Karaf container to allow network operators to customize installation using only the features they want
  2. A new user interface, dlux (the OpenDayLight User eXperience) for client-side MVW (Model View Whatever)
  3. Group Base Policy for an application-centric way of expressing policy
  4. Accounting, authorization and authentication for enhanced security
  5. The BGPCEP project now supports provisioning segment routing through PCEP 

With Helium there are no base, virtualization or service provider editions. Instead, bundles are supported through karaf features. Unlike the first (Hydrogen) release, Helium is targeted towards production environments. 

Out of the Box Experience 

After downloading the pre-built zip file, it is straightforward to run the karaf container with the ‘bin/karaf’ script. The ‘help’ command in the console provides a list of karaf commands Continue reading

Confusing Times in Networking and Cognition Jumps


I’ve been researching four different and distinct types of networking in the last few weeks. I’m finding that the cognition required to jump between technologies is making my head hurt. Here is a summary of four technology areas that interest me this week. Optical Networking As part of research project I have been getting deep […]

The post Confusing Times in Networking and Cognition Jumps appeared first on EtherealMind.

Announcement: The Hot Aisle Newsletter

I’ve launched a newsletter called The Hot Aisle. Why might you care? The Hot Aisle is a personal look at my real life IT engineering projects, thoughts about the networking industry I won’t publish anywhere else, my growingly contrarian views on social media, good stuff I’ve read, and comments from fellow Hot Aisle readers. The content is […]

Questions for Photography Enthusiasts

It’s no secret that I’m something of a photography enthusiast. To me, photography is a relaxing puzzle of how to assemble all the various pieces—setting, lighting, exposure, composition, etc.—to create just the right image. I’m not an expert, but that’s OK; I just do this for fun and to relax. If you’d like to see a small sampling of some of the photos I’ve taken, I publish some of them here on 500px.com.

I know that a fair number of folks in the IT industry are also photo enthusiasts, and so I was curious to hear some feedback from fellow enthusiasts about their photography workflows. In particular, I’m curious to know about how others answer these questions:

  • What formats do you use with your photos? (I’ve been shooting in RAW—NEF, specifically, since I’m a Nikon guy—then converting to Adobe DNG for use with Lightroom.)
  • How do you handle long-term storage of your photos? (Once I have the photos in DNG in Lightroom, then I’ve been archiving the RAW files on my Synology NAS.)
  • What pictures do you keep—all of them, or only the best ones? (So far, I’ve been keeping all the RAW files, archiving when Continue reading

SDN Market Sizing Redux

In April 2013, Plexxi teamed up with SDNCentral to take a look at how the SDN market might emerge. The original post along with supporting info graphic and written analysis can be found here. At a high level, the major takeaway was that we predicted that between 30 and 40 percent of the networking market would be influenced by SDN by 2018. At the time, this was BY FAR the most aggressive take on SDN. IDC had been projecting a little more than $3B by 2018, which would put their estimates somewhere around 5% of the overall networking spend.

So 18 months later, how do I feel about the analysis?

SDN spend is largely substitutive

In the original analysis, I made the point that SDN spend is not likely to be net-new dollars coming into the networking industry but rather a shift in dollars from traditional networking equipment to SDN-enabled equipment.

How’d I do? I’d say that this was spot on. Of course, this was the easiest of the predictions at the time. It is rare that dollars are created; they are usually shifted from somewhere else. Here, all I was really predicting was that the somewhere else was other Continue reading

Questions for Photography Enthusiasts

It’s no secret that I’m something of a photography enthusiast. To me, photography is a relaxing puzzle of how to assemble all the various pieces—setting, lighting, exposure, composition, etc.—to create just the right image. I’m not an expert, but that’s OK; I just do this for fun and to relax. If you’d like to see a small sampling of some of the photos I’ve taken, I publish some of them here on 500px.com.

I know that a fair number of folks in the IT industry are also photo enthusiasts, and so I was curious to hear some feedback from fellow enthusiasts about their photography workflows. In particular, I’m curious to know about how others answer these questions:

  • What formats do you use with your photos? (I’ve been shooting in RAW—NEF, specifically, since I’m a Nikon guy—then converting to Adobe DNG for use with Lightroom.)

  • How do you handle long-term storage of your photos? (Once I have the photos in DNG in Lightroom, then I’ve been archiving the RAW files on my Synology NAS.)

  • What pictures do you keep—all of them, or only the best ones? (So far, I’ve been keeping all the RAW files, archiving when Continue reading

Openstack distribution

In the last few months, following were some acquisitions that happened: Cisco acquiring Metacloud, EMC acquiring Cloudscaling, HP acquiring Eucalyptus. Metacloud and Cloudscaling have Openstack based distributions, Eucalyptus has a cloud OS similar to Openstack. This set of acquisitions prompted me to look little closely at Openstack distributions and following blog is a result of this. … Continue reading Openstack distribution →
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