Stu Radnidge

Raspberry Router on a Stick

One of the great use cases for a Raspberry Pi is for a low cost, low power router for your home network - great for implementing pseudo-network segregation, but obviously not something that can be made secure with a single interface.

Contrary to a lot of things you’ll find on the internets, you don’t need 2 physically separate interfaces (unless you also want security), and you don’t need a sub-interface - 2 IP addresses will happily live on the same interface.

Say for example your internal network is currently 192.168.1.0/24, and that’s where your inside modem interface lives. Your Raspberry Pi is at 192.168.1.253, and you want to add a new network 10.0.0.0/24.

1. Create a manual route on your modem for network 10.0.0.0/24 with a default gateway of the Raspberry Pi IP address (in this case 192.168.1.253)

2. On the Pi, add a new IP to eth0
ip addr add 10.0.0.254/24 dev eth0

- to make this persistent, open up /etc/network/interfaces and add the following after whatever you have in there already

up ip addr add 10.0.0.254/24 dev eth0 

3. On the Pi, ensure ip forwarding is enabled
sysctl net.ipv4.ip_forward = 1

- to make this persistent, add the following to /etc/sysctl.conf

net.ipv4.ip_forward = 1

4. On the Pi, disable sending redirects to stop hosts from skipping the “router”
sysctl net.ipv4.conf.all.send_redirects = 0

- to make this persistent, add the following to /etc/sysctl.conf

net.ipv4.conf.all.send_redirects = 0

And that’s it - you can now spin up machines on 10.0.0.0/24 and have everything talk to everything else!

Oracle Open Sources Solaris, HotSpot JVM

In a surprise move, Larry Ellison reportedly announced today that his company Oracle would be open-sourcing Solaris and the HotSpot Java Virtual Machine.

This is of course not the first time Solaris has been open sourced - Sun originally did this with the Solaris 10 release, however Oracle originally closed the source shortly after their acquisition of Sun in 2010.

The motive, like everything that Oracle does, is purely financial. “With all these startups wasting their much more limited resources on not only further developing features native to Solaris, but bringing new features such as KVM that can’t be incorporated into Solaris while it remains closed, I just thought ‘why am I wasting money on all these kernel engineers when I can get other people to do the work for FREE!’” the CEO apparently said, continuing with “I don’t know why I didn’t just keep it open to begin with - what was I thinking. I have my application and database cash cows, and everyone knows you can’t make money from a server OS - I mean look at OEL, we can’t even give that away. Our wikipedia page doesn’t even mention Solaris as a software product we own, that’s how insignificant it is.”

As for open sourcing the HotSpot Java Virtual Machine, the same logic applied: “There is a significant number of people contributing to the Apache Foundation’s Java-based projects, as well as companies like Red Hat and EMC (via Pivotal Initiative) dedicating plenty of resources to open source commercial Java-based products. Giving up HotSpot will just mean more people using Java instead of these other pissant non-Enterprise languages, like JavaScript.”.

As a result of the move, there will be an estimated 7000 job losses at Oracle. But there is an upside to the layoffs - all the money previously paid to those engineers will now be donated to the Ellison Foundation charity.

The community that has formed around Illumos (the fork of the Open Solaris kernel), although small, is already fractured. There are at least 4 commercially backed distributions from Joyent, Delphix, OmniTI and Nexenta - each with their own package manager as well as a slew of other minor inconsistencies. The purely community driven OpenIndiana has failed to muster significant support in the midst of these alternatives. It is hoped that now the golden source has been re-opened, those fractures will disappear and the community will come together once more.

Although it may also lead to some heavy hitting departures from the Illumos community. I called Bryan Cantrill (former Sun kernel engineer / current VP of engineering at Joyent) this morning to tell him about the news, and after a tirade of abuse broken only by primal sounding screams, he concluded with “Fuck this, we’re moving to Linux.” before hanging up in a manner that suggested his phone had been smashed against a wall. And not one that was nearby.

I Know What You Did Last S… aturday

After a lengthy spell of rain, snow, and generally foul weather, when I awoke to a clear sunny day this morning I just had to get out. With the missus out for the day, I thought why not go on a little London walkabout - the kind of thing I used to do every weekend when I first arrived here nearly 6 years ago.

Not long ago I bought a 5th generation iPod Touch, with the intention of using the camera on it in place of the Canon point-and-shoot we’ve had for many many years. And so I thought I’d try a little experiment, by doing a kind of photo walking tour of some parts of London that I like, which are within walking distance of where I live.

Unfortunately this idea didn’t dawn on me until I had already reached the Barbican Centre (i was paying a visit to the library there), so there are a few little things I could’ve shot on the the way there. But not to worry.

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The Simplicity of Independence

No, this post is not Dr Stu giving relationship advice. Hopefully you’ll keep reading now ;)

I was reminded of an experience I went through a little while ago, whereby the oh-so-typical reductionist approach was taken by managers overseeing the development of a new system. That is, after identifying that there was significant overlap between a new proposed component and an existing component (albeit one that would apparently require “little modification” to provide equal functionality), in the name of DRY it was decided that a dependency would be introduced rather than a duplication.

The problem was, the overlap was more perceived than real.

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Hadoop - to V, or not to V?

Today I delivered a cheekily titled (alas, I cannot take credit for that title - it was a workmate, who I shall not name!) session at the London VMware User Group, wherein I attempted to explain Hadoop for the uninitiated and then present some considerations for virtualising Hadoop nodes. All in 45 mins. Which is potentially mind melting stuff, if you have never looked into Hadoop before - not because it is difficult material, it’s just dense.

I think I did a pretty good job of getting my points across, however I might not have emphasized enough that everything in there is with reference to centralised multi-tenant SAN based VMware deployments. That is, the kind of VMware infrastructure that 99% of people have deployed in production today.

That distinction is important, because a lot of the messaging that came out from VMware originally suggested that it was reasonable to stand up Hadoop clusters on the homogenous pool of compute that you use for non-distributed IO intensive applications.

So just be clear about that if you have a look through the deck - deploying virtual Hadoop slaves backed with local disk may or may not be much less efficient than bare metal, but I don’t have the data or experience to say either way. All I can say, is deploying production Hadoop slaves onto SAN based virtual infrastructure is not just a terrible idea - it’s also a stupid one.

Future of Guerilla Marketing?

I was having a laugh with my mate Tim this morning about a phone system bug that woke up over 10K employees very early today (we were both victims).

I remarked how I had looked at the number through bleary eyes when my mobile rang, not recognised it and immediately thought of an Apple TV ad playing in the UK currently - this one called ‘Dreams’, to be precise (did you know Apple named their commercials? I didn’t!).

Which sounded like a great way to do some Duplicity style corporate black ops to us! Imagine consumer companies “planting” (or at least paying off) employees at Fortune 500 companies to promote the consumption of their products. Could be anything from as subtle as constantly pestering the corporate caterer or vending machine provider to stock a particular brand of something, all the way through to something as blunt as “let’s show these ads about the do not disturb features in our phone for a few weeks, then wake up employees of company X in region Y at a really inconvenient time of the morning”.

Imagine a “temp resources” company that required all their employees engage in the more subtle behaviours, in return for payments to the resourcing company from an advertising company… kind of like an AdWords for people? Would probably be cheaper than mass retina scanning, and would be operating on a whole other level (ie suggestion instead of visual assault).

Not suggesting for a minute that this kind of thing actually happens In Real Life™, but with lawsuits like this flying around is it really that far fetched an idea?

Engineering in the Enterprise

I was watching this video of the always influential (or if not, at least entertaining :) Jason Hoffman and Bryan Cantrill from the Monki Gras event last year. It goes without saying that when either of these guys speak, you should listen.

Towards the end (around 40mins into it), Bryan says something along the lines of engineering being about figuring out the difference between the things are possible within the constraints at hand, and the things that are possible (as per the infinite monkey theorem). Which got me thinking about engineering in the Enterprise, as that what I have done for the bulk of my working life thus far.

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Sensationalist Correlation

As much as I hate to start the year off on a kind of negative foot, I can’t let this recent article, which proposes a causal link bewteen lead exposure and crime, go unexamined. The author, Kevin Drum, first dismisses prior analyses of social phenomena as being “purely correlative”, then goes on to present a causal explanation using… pure correlation, primarily from the work of Rick Nevin.

Going by the number of tweets that appeared in my timeline, apparently there were many in my circles who didn’t immediately see the folly.

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Passwords: Just Use the Mnemonic

For many years I have used an application to generate and store reasonably long complex passwords for the various web services and applications that I use. The more common ones, such as iTunes, Google and Twitter, I end up committing to memory. The downside of course is that for everything else I actually don’t know what my password is, meaning if I ever need it and I don’t have a PC and my database (I use PasswordSafe) to hand, I’m screwed

The only way for me to do this is using a mnemonic - alas, random (for all intents and purposes) strings of double digit length are not something my brain retains easily. But then I thought, why bother with the “complex” password and just go for the mnemonic itself? You’d think I would have realised this the first time I saw http://xkcd.com/936/, but alas I didn’t.

Let’s try an example. Here’s the kind of password I might use:

QuMEtH!kGE+j4YM8RzdpL:nGm

And the mnemonic I might have come up with:

Qu MEtH! kGE + j 4 Y M8 Rz dpL nG m

“cue method man cagey and just for you mate RZA double platinum nextgen machine”

Which password is “stronger” :). Now if only everyone would get of the ridiculous “password between 8 and 15 characters” type limitations!

Chinwag with Mike

A couple of weeks ago (pre-‘reverse goatee’) I had the pleasure of being on Mike Laverick’s chinwag video / podcast. It’s always good chatting with Mike, and every time I do I remember those times when I was a newbie back in Australia and Mike’s site was pretty much the only (but certainly the best) source of VMware info on the web. How time flies.

I did make some slight errs during the chat however, the worst of which was somehow saying “dynamic DHCP” when of course I meant to say “dynamic DNS”! Mike’s brain heard the correct thing and just carried on the conversation as normal, but yeh… pretty stupid lol. Getting Geoffrey West’s surname wrong was slightly more forgivable.

Anyway I refer to a few things you should watch, so here are the links for those:

Geoffrey West: The surprising math of cities and corporations

Jason Hoffman: WAR SIGNALS: INDUSTRIALIZATION, MOBILIZATION AND DISRUPTION

Towards the end I also mention something about innovation and organisational structure, which was with reference to this excellent post:

An Operations Mindset Is at Odds with Innovation

And of course, catch my interview here! Thanks Mike :)