What's That Noise?! [Ian Kallen's Weblog]

Hub-a-dub-bub, feed clouds in a tub

spidaman — Thu, 10 Sep 2009 12:35:37 -0700

While at Technorati, I observed a distinct shift around summer of 2005 in the flow of pings from largely worthwhile pings to increasingly worthless ones. A ping is a simple message with a URL. Invented by Dave Winer, it was originally implemented with XML-RPC but RESTful variants also emerged. The intention of the message is "this URL updated." For a blog, the URL is the main page of the blog; it's not the feed URL, a post URL ("permalink") or any other resource on the site - it's just the main page. Immediately, that narrow scope has a problem; as a service that should do something with the ping, the notification has no more information about what changed on the site. A new post? Multiple new posts? Um, what are the new post URL(s)? Did the blogroll change? And so on. Content fetching and analysis is cheap; network latencies, parsing content and doing interesting stuff with it is easy at low volumes but is difficult to scale.

In essence, a ping is a cheap message to prompt an expensive analysis to detect change. It's an imbalanced market of costs and benefits. Furthermore, even if the ping had a richer payload of information, pings lack another very important component: authenticity. These cheap messages can be produced by anybody for any URL and the net result I observed was that lots of people produced pings for lots of things, most of which weren't representative of real blogs (other types of sites or just spam) or real changes on blogs, just worthless events that were resource intensive to operate on. When I left Technorati in March (2009), we were getting around 10 million pings a day, roughly 95% of them of no value. Pings are the SMTP of the blogosphere; weak identity systems, spammy and difficult to manage at scale.

Besides passively waiting for pings, the other method to find things that have changed is to poll sites. But polling is terribly inefficient. To address those inefficiencies, FriendFeed implemented Simple Update Protocol. SUP is reminiscent of another Dave Winer invention, changes.xml however SUP accounts for discovery and offers a more compact format.

But SUP wasn't the first effort to address the aforementioned deficiencies, 2005 saw a lot of activity around something called "feedmesh." Unfortunately, the activity degenerated into a lot of babble; noise I attribute to unclear objectives and ego battles but I'm sure others have their own interpretation. The feedmesh discussion petered out and little value beyond ping-o-matic and other ping relayers emerged from it. Shortly thereafter SixApart created their atom stream, I think spearheaded by Brad Fitzpatrick. The atom stream is essentially a long lived HTTP connection that streams atom elements to the client. The content flow was limited to SixApart's hosted publishing platforms (TypePad, LiveJournal and Vox) and the reliability wasn't that great, at least in the early days, but it was a big step in the right direction for the blog ecosystem. The atom stream was by far the most efficient way to propogate content from the publishing platform to interested parties such as Technorati operating search, aggregation and analytic systems. It eliminates the heavyweight chatter of cheap ping messages and the heavyweight process that follows: fetch page, discover feed, fetch feed, inspect contents and do stuff with it.

So here we are in 2009 and it feels like deja-vu all over again. This time Dave is promoting rssCloud. rssCloud does a waltz of change notification; the publisher notifies a hub, the hub broadcasts notifications to event subscribers and the subscriber does the same old content fetch and analysis cycle above. rssCloud seems fundamentally flawed in that it is dependent on IP addresses as identifiers. Notification receivers who must use new a IP address must re-subscribe. I'm not sure how an aggregator should distribute notificaton handling load across a pool of IP addresses. The assumption is that notification receivers will have stable, singular IP addresses; rssCloud appears scale limited and a support burden. The focus on specification simplicity has its merits, I think we all hate gratuitous complexity (observe the success of JSON over SOAP). However, Dave doesn't regard system operations as an important concern; he'll readily evangelize a message format and protocol but the real world operability is Other Peoples Problem.

Pubsubhubub (hey, Brad again) has a similar waltz but eliminates the content fetch and analysis cycle ergo it's fundamentally more efficient than rssCloud's waltz. Roughly, Pubsubhubub is to the SixApart atom stream what rssCloud is to old school XML-RPC ping. If I were still at Technorati (or working on event clients like Seesmic, Tweetdeck, etc), I would be implementing Pubsubhubbub and taking a pass on rssCloud. With both systems, I'd be concerned with a few issues. How can the authenticity of the event be trusted? Yes, we all like simplicity but looking at SMTP is apt; now mail systems must be aware of SPF, DKIM, SIDF, blahty blah blah. Its common for mail clients to access MTA's over cryptographically secure connections. Mail is a mess but it works, albeit with a bunch of junk overlaid. I guess this is why Wave Protocol has gathered interest. Anyway, Pubsubhubbub has a handshake during the subscription processes, though that looks like a malicious party could still spin up endpoints with bogus POSTs. I'd like to see an OAuth or digest authentication layer in the ecosystem. Yea, it's a little more complicated, but nothing onerous... suck it up. Whatever. Brad knows the authenticity rap, I mean he also invented OpenID (BTW, we adopted OpenID at Technorati back in 2007). At Technorati we had to implement ping throttling to combat extraneous ping bots; either daemons or cron jobs that just ping continuously, whether the URL has changed or not. You can't just blacklist that URL, we don't know it was the author generating those pings, there's no identity authenticity there. We resorted to blocking IP addresses but that scales poorly and creates other support problems. We had 1000's of domain names blocked and whole class C networks blocked but it was always a wackamole exercise; so much for an open blogosphere, a whitelist is the only thing that scales within those constraints. Meanwhile, back to rssCloud and Pubsubhubbub, what event delivery guarantees can be made? If a data center issue or something else interrupts event flow, are events spooled so that event consumption can be caught up? How can subscribers track the authenticity of the event originators? How can publishers keep track of who their subscribers are? Well, I'm not at Technorati anymore so I'm no longer losing any sleep over these kinds of concerns but do I care about the ecosystem. For more, Matt Mastracci is posting interesting stuff about Pubsubhubbub and a sound comparison was posted to Techcrunch yesterday.

rsscloud pubsubhubbub ping

Business Models in Consulting, Contracting and Training

spidaman — Sun, 2 Aug 2009 20:57:08 -0700

Since leaving Technorati last spring, I've been working independently with a few entrepreneurs on their technical platforms. This has mostly entailed working with tools around Infrastructure-As-A-Service (AWS), configuration management (Chef and RightScale), search (Solr) and learning a lot about programming and going into production with ruby and rails. I've spoken to a number of friends and acquaintances who are working as consultants, contractors, technical authors and trainers. Some are working as lone-wolves and others working within or have founded larger organizations. I'm always sniffing for where the upside opportunities are and the question that comes to my mind is: how do such businesses scale?

A number of technology services companies that I've taken notice of have been funded in the last year or so including OpsCode, Reductive Labs, Cloudera and Lucid Imagination. I think all of these guys are in great positions; virtual infrastructure (which is peanut butter to the chocolate of IaaS), big data and information retrieval technologies provide the primordial goo that will support new mobile, real time and social software applications. They are all working in rapid innovation spaces that hold high value potentials but also new learning and implementation challenges that rarefy specialized knowledge.

Years ago when I was working with Covalent Technologies, we tried to build a business around "enterprise open source" with Apache, Tomcat, etc as the basis. Packaging and selling free software is difficult. On the one hand, offering a proven technology stack configuration to overcome the usual integration and deployment challenges as well as providing a support resource is really valuable to Fortune 500's and such. However, my experience there and observations of what's happened with similar businesses (such as Linuxcare and SpikeSource) has left me skeptical how big the opportunity is. After all, while you're competing with the closed-source proprietary software vendors, you're also competing with Free.

The trend I'm noticing is the branching out away from the packaging and phone support and into curriculum. Considering that most institutional software technology education, CS degrees, extended programs, etc have curricula that are perpetually behind the times, it makes sense that the people who possess specialized knowledge on the bleeding edge lead the educational charge. Lucid Imagination, Cloudera and Scale Unlimited are illustrating this point. While on-premise training can be lucrative, I think online courseware may provide a good answer to the business scale question.

For myself, I'm working with and acquiring knowledge in these areas tactically. Whatever my next startup will be, it should be world-changing and lucrative. And I'll likely be using all of these technologies. Thank goodness these guys are training the workforce of tomorrow!

startups scalability entrepreneuring

Configuring Web Clouds with Chef

spidaman — Thu, 21 May 2009 12:30:07 -0700

I'm not generally passionate about network and system operations, I prefer to focus my attention and creativity on system and software architectures. However, infrastructure provisioning, application deployment, monitoring and maintenance are facts of life for online services. When those basic functions aren't functioning well, then I get passionate about them. When service continuity is impacted and operations staff are overworked, it really bothers me; it tells me that I or other developers I'm working with are doing a poor job of delivering resilient software. I've had many conversations with folks who've accepted as a given that development teams and operations teams have friction between them; some even suggest that they should. After all, so goes that line of thinking, the developers are graded on how rapidly they implement features and fix bugs whereas the operators are graded on service availability and performance. Well, you can sell that all you want but I won't buy it.

In my view, developers need to deliver software that can be operated smoothly and operators need to provide feedback on how smoothly the software is operating; dev and ops must collaborate. I accept as a given that developers

Use source control
Write unit tests (after the fact or before/during TDD style)
Write functional and integration tests
Maintain a build system for running test harnesses and packaging code
Document internal architecture and operating interfaces
Plan for change with respect to scale charactistics and functionality

Conversely, I accept as a given that operators

Use configuration management
Automate infrastructure provisioning, code deployment and rollback
Monitor infrastructure and application metrics

I don't want to oversimplify, there's more to the obligations that dev and ops have to each other in order to collaborate effectively. What I've noticed though is that a lot of operators might be skilled with configuring specific server infrastructure or performing OS analysis but configuration management and automation requires using really good tools that they lack. I've seen situations where the available tools are perceived as too complicated and so tools are developed that usually consist of a lot of specialized shell scripts (or perhaps it's just plain old NIH). Cfengine is a good start but the reports I have is that it's difficult to work with and, if you're not very careful, may automatically manage to misconfigure your systems. Puppet was developed to be a more powerful system for configuration management but the feedback I've seen on it is adding new functionality is hard; it has its own configuration language and when you want to extend it you have to deal with a lot of complicated mechanisms. Chef was developed to answer that frustration; by making the configuration language a DSL on top of an already widely used scripting language (ruby), the chef code base provides an easier way to extend it and the chef codebase itself is reportedly an order of magnitude smaller and simpler than puppet's (cavaet: I generally distrust SLoC metrics but just sayin').

So I've been giving Chef a test-drive for this infrastructure-on-EC2 management project that's been cooking. The system implemented the following use cases:

Launch web app servers on EC2 with Apache, Passenger, RoR (+other gems) and overlay a set of rails apps out of git
Launch a pair of reverse proxies (with ha-proxy) in front of the app servers - and reconfigure them when the set of app servers is expanded or contracted
Configure the proxy for failover with heartbeat
Add new rails apps to the set of app servers
Updating/rolling back rails apps

The system is enabled through a combination of the EC2 API (via RightAWS) and Chef's REST API as well as using chef-deploy (think: Capistrano run by a system provisioning agent) to augment Chef's functionality. So far, it seems to be working great!

There's a lot of energy in the Chef community (check out Casserole), combined with monitoring, log management and cloud technologies, I think there's a lot of IT streamlining ahead. Perhaps the old days of labor and communication intensive operations will give way to a new era of autonomic computing. I'll post further about some of the mechanics of working with ruby, rails, chef, EC2, chef-deploy and other tools in the weeks ahead (particularly now that EC2 has native load balancing, monitoring and auto-scaling capabilities). I'll also talk a bit about this stuff at a Velocity BoF. If you're thinking about attending Velocity, O'Reilly is offering 30% off to the first 30 people to register today with the code vel09d30 today (no I'm not getting any kinduva kickback from O'Reilly). And you can catch Infrastructure in the Cloud Era with Adam Jacob (Opscode), Ezra Zygmuntowicz (EngineYard) to learn more about Chef and cloud management.

chef puppet cfengine ec2 aws ruby cloud computing velocity

Cloning VMware Machines

spidaman — Tue, 31 Mar 2009 09:12:22 -0700

I bought a copy of VMware Fusion on special from Smith Micro (icing on the cake: they had a 40% off special that week) specifically so I could simulate a network of machines on my local MacBook Pro. While I've heard good things about Virtual Box, one of the other key capabilities I was looking for from MacIntosh virtualization software was the ability convert an existing Windows installation to a virtual machine. VMware reportedly has the best tools for that kind of thing. I have an aging Dell with an old XP that I'd like to preserve when I finally decide to get rid of the hardware; when it's time to Macify, I'll be good to go.

I started building my virtual network very simply, by creating a CentOS VM. Once I had my first VM running, I figured I could just grow the network from there; I was expecting to find a "clone" item in the Fusion menus but alas, no joy. So, it's time to hack. Looking around at the artifacts that Fusion created, a bunch of files in a directory named for the VM, I started off by copying the directory, the files it contained that had the virtual machine name as components of the file name and edited the metadata files ({vm name}.vmdk/.vmx/.vmxf). Telling Fusion to launch that machine, it prompted if this was a copy or a moved VM - I told it that it was copied and the launch continued. Both launched VM's could ping each other so voila: my virtual network came into existence.

I've since found another procedure to create "linked clones" in VMware Fusion. It looks like this will be really useful for my next scenario of having two different flavors of VM's running on my virtual network. The setup I want to get to is one where I can have "manager" host (to run provisioning, monitoring and other management applications) and cookie-cutter "worker" hosts (webservers, databases, etc). Ultimately, this setup will help me tool up for cloud platform operations; I have more Evil Plans there.

So all of this has me wondering: why doesn't VMware support this natively? Where's that menu option I was looking for? Is there an alternative to this hackery that I just overlooked?

vmware virtualization centos vmware fusion vm cloning

Going to Metallica's Rock and Roll Hall of Fame Induction

spidaman — Thu, 12 Mar 2009 12:22:51 -0700

Those 25 things you should know about me memes circulating rarely interest me (honestly, I don't care that you have a collection of rare El Salvadoran currency). However, one thing that my friends know but regular readers may not is that I have a fairly eclectic background. Did you know that I used to hang around the art department's hot glass studio in college to blow glass? Did you know that I learned to program in Pascal when I was in college and hated it? Yea, yea, I don't care much anymore either. But anyway, back in the 80's I was friends with this Danish dude from LA who shared my interest in the underground heavy metal scene that was burgeoning, particularly in Britain ("New Wave of British Heavy Metal" AKA NWOBHM) and Europe. We used to trade records and demos (the first Def Leppard 3 song EP on 9" vinyl, I was tired of it so I traded him for a bunch of Tygers of Pan Tang and other crap I didn't own already). I think he, like myself, used to pick up copies of Melody Maker and Sounds at the local record store to read about what was going on overseas. Eventually, Kerrang! came out providing fuller coverage of the metal scene, complete with glossy pictures. But in the meantime back in San Francisco, I helped a friend of mine (Ron Quintana) operate his fanzine Metal Mania (don't be confused, the name was re-appropriated by various larger publishing concerns at different times in the years since but none of them had any relationship to the original gangstas).

Back in the day, Howie Klein was a muckety muck in the music industry, haunting the local clubs like The Old Waldorf and Mabuhay Gardens. Howie hooked us up with a show on KUSF. I dubbed the show Rampage Radio, it ran in the wee hours every Saturday night (right after Big Rick Stuart finished up his late night reggae show with those dudes from Green Apple Records on Clement Street). In between hurling insults at "album oriented rock" and big-hair metal bands (posers!), we played a lot of stuff you couldn't hear anywhere else. Among the many obscure noises we aired were demos from East Bay metalheads Exodus. Amazingly, Rampage Radio is still on the air. Well, that Danish kid and one of the guys I befriended from Exodus were Lars Ulrich and Kirk Hammett, respectively. In short order, they would be playing together in a band Lars named Metallica (after haggling with Ron about not taking that name for the 'zine).

I eventually lost interest in the metal scene (not enough innovation, too much sound-alike derivatives to keep me listening); even though the music from then is still on my playlist, my repertoire has broadened widely (talk to me about gypsy style string jazz, please). I've been peripherally in touch with friends from back then. Over the years, I'd go to a few Metallica shows but the guys are always mobbed at the backstage parties, there's not much of an opportunity to actually talk about anything. Anyway, we have little in common now. I develop software and crazy assed online services; they tour the world to perform in front of throngs. And I don't drink Jaegermeister anymore. In 2000, I introduced one of the friends I've stayed in touch with, Brian Lew, who also had a fanzine Back In The Day, to editors at salon.com (where I was working at the time). He contributed a great article expressing a sentiment that I shared, dismay at Metallica's war on Napster. I don't think I've actually talked to Lars in 15 years. After seeing news coverage of him ranting about how people (his most valued asset: his fans) where ripping him off, I'm not sure I wanted to. But I think we're all over that now, let's just play Rock Band and fuhgedaboutit.

So here we are decades later and Metallica hasn't just warped the music industry, they are the industry. They're up there with Elvis and the Beatles and all of that (except, barring Cliff Burton, they're not dead). Last week, Brian pings me that Q-Prime (Metallica's management company in New York) is trying to reach me. After a few phone calls, it turns out that Metallica is honoring a handful of us old-schoolers by inviting us to a big shindig in Cleveland for their Rock and Roll Hall of Fame induction next month. How cool is that?! I'm still kind blown away that this is really happening (am I being punkd??).

So, I may be leaving Technorati but I'm going to the Rock and Roll Hall of Fame! w00t! That tune keeps humming through my conscience, "...living in sin with a safety pin, Cleveland rocks! Cleveland rocks!" but the way it sounds in my head, it's ganked up, roaring from a massive PA and a wall of Marshall stacks. So now you know what my plans will be in a few weeks and now you've learned a dozen or so things about me (if not 25) that you may not have known before.

metallica rock and roll hall of fame metal kusf cleveland nwobhm

More Changes At Technorati (this time, it's personal)

spidaman — Tue, 10 Mar 2009 14:06:20 -0700

My post last week focused on some of the technology changes that I've been spearheading at Technorati but this time, I have a personal change to discuss. When I joined Technorati in 2004, the old world of the web was in shambles. The 1990's banner-ads-on-a-CPM-basis businesses were collapsed. The editorial teams using big workflow-oriented content management system (CMS) infrastructure (which I worked on in the 90's) were increasingly eclipsed by the ecosystem of blogs. Web 2.0 wasn't yet the word on everyone's lips. But five years ago, Dave Sifry's infectious vision for providing "connective tissue" for the blog ecosystem, tapping the attention signals and creating an emergent distributed meta-CMS helped put it there. Being of service to bloggers just sounded too good, so I jumped aboard.

Through many iterations of blogospheric expansion, building data flow, search and discovery applications, dealing with data center outages (and migrations) and other adventures, it's been a long strange trip. I've made a lot of fantastic friends, contributed a lot of insight and determination and learned a great deal along the way. I am incredibly proud of what we've built over the last five years. However today it's time for me to move on, my last day at Technorati will be next week.

Technorati has a lot of great people, technology and possibilities. The aforementioned crawler rollout provides the technology platform with a better foundation that I'm sure Dorion and the rest of the team will build great things on. The ad platform will create an abundance of valuable opportunities for bloggers and other social media. I know from past experiences what a successful media business looks like and under Richard Jalichandra's leadership, I see all of the right things happening. The ad platform will leverage Technorati's social media data assets with the publisher and advertiser tools that will make Technorati an ad delivery powerhouse. I'm going to remain a friend of the company's and do what I can to help its continued success, but I will be doing so from elsewhere.

I want to take a moment to thank all of my colleagues, past and present, who have worked with me to get Technorati this far. The brainstorms, the hard work, the arguments and the epiphanies have been tremendously valuable to me. Thank You!

I'm not sure what's next for me. I feel strongly that the changes afoot in cloud infrastructure, open source data analytics, real time data stream technologies, location based services (specifically, GPS ubiquity) and improved mobile devices are going to build on Web 2.0. These social and technology shifts will provide primordial goo out of which new innovations will spring. And I intend to build some of them, so brace yourself for Web 3.0. It's times like these when the economy is athrash that the best opportunities emerge and running for cover isn't my style. The next few years will see incumbent players in inefficient markets crumble and more powerful paradigms take their place. I'm bringing my hammer.

technorati

Welcome to the Technorati Top 100, Mr. President

spidaman — Wed, 4 Mar 2009 22:59:16 -0800

Since its inception just 6 weeks ago, the White House Blog has had a tremendous center of gravity. I noted the volume of links coming in to the White House Blog after the first week. This is an existential moment for the blogosphere because today the White House Blog has 3216 links from 2323 blogs. And so it's official: the White House Blog has reached the Technorati Top 100.

I find myself reflecting on what the top 100 looked like four years ago, after the prior presidential inauguration, and what it looks like today; the blogosphere is a very different place. Further down memory lane, who recalls when Dave Winer and Instapundit were among the top blogs? Yep, most of the small publishers have been displaced by those with big businesses behind them. Well, at least BoingBoing endures but Huffpo and Gizmo better watch out, here comes Prezbo.

technorati white house inauguration blog

New Crawlers At Technorati

spidaman — Wed, 4 Mar 2009 20:31:16 -0800

A lot of changes are afoot at Technorati. Over the last year or so, we've been looking inward at the infrastructure and asking ourselves, "How can we do this better?". The data spigot that Technorati builds on was the first thing to focus on, it's a critical part in one leg of the back-end infrastructure tripod. The tripod consists of data acquisition, search and analytics Technorati; while the ping handling and queuing are relatively simple affairs the crawler is the most sophisticated of the data acquisition subsystems. It's proper functioning is critical to the functioning of the other legs; when it doesn't function well, search and analytics don't either (GIGO="garbage in/garbage out").

As Dorion mentioned recently, we're retiring the old crawler. Why are we giving the old crawler getting an engraved watch and showing it to the door? Well, old age is one reason. The original spider is a technology that dates back to 2003, the blogosphere has changed a lot since then and we have a much better developed understanding of the requirements. The original spider code has presented a sufficient number of GIGO-related and code maintenance challenges to warrant a complete re-thinking. It contrasts starkly with the replacement.

Data model: There are a lot of ways to derive structural information out of the pages and feeds that a blog presents. The old spider used event driven parses, building a complex state as it went with flat data structures (lists and hashes). The new one uses the composed web documents to populate a well-defined object model; all crawls normalize the semi-structured data found on the web to that model.
Crawl persistence: The old spider was hard-wired to persist the aforementioned data structure elements to relational databases (sharded MySQL instances) while it was parsing, so that the flow of saving parsed data was closely coupled with parsing events, forsaking transactional integrity and consuming costly resources. The new spider composes and saves its parse result as a big discreet object (not collections of little objects in an RDBMS). This reduced the hardware footprint by an order of magnitude.
Operational visibility: Whether a blog's page structure was understood (or not), the feed was well formed (or not) or any of the many other things that determine the success or quality of a blog's crawl was opaque under the old spider. With the new spider, detailed metadata and metrics are tracked during the crawl cycles. This better enables the team to support bloggers and extend the system's capabilities.
Unit tests: Wherever you have complex, critical software you want to have unit tests. The old spider had almost no unit tests and was developed in a way that made testing the things that mattered most exceptionally difficult. The new spider was developed with a test harness upfront, it now has hundreds of tests that validate thousands of aspects of the code. The test are uniformly invoked by the developers and automatically whenever the code is updated (AKA under continuous integration).

The old spider didn't leverage packages to logically separate the different concerns (fetching, parsing, validation, change determination, etc), the aforementioned flat data structures, mingling of concerns and absence of unit tests made changing it exceedingly difficult. Now, we have a whole that is greater than the sum of the parts; having a well defined data model, sensible persistence, operational visibility and unit tests has added up to an order of magnitude improvement across several dimensions. The real benefits are seen when we've shown that the system is easy to change, I mentioned this several weeks ago when I noted the ease with which we could adapt custom requirements to crawl the White House blog.

Another change that we've made is to the legacy assumption that everything that pings is a blog. That assumption proved to be increasingly untenable as the ping meme spread amongst those who didn't really understand the difference between some random page and a blog, nefarious publishers (spammers) and other perpetrators of spings. Over 90% of the pings hitting Technorati are rejected outright because they've been identified as invalid pings. A large portion of the remainder are later determined to be invalid but we now have a rigorous system in place for filtering out the noise. We've reduced the spam level considerably (as mentioned in a prior post). For instance, there's a whole genre of splogs that are pornography focused (hardcore pictures, paid affiliate links, etc) that previously plagued our data; now we've eliminated a lot of that nonsense from the index.

Here are a pair of charts showing the daily occurrence of a particular porn term in the index.

6 month retrospective as of November 3rd, 2008:

6 month retrospective today, 5 months later:

As you can see, that's an order of magnitude reduction; 90% of the occurrences of that term was spam.

So what's next for the crawler? We've got some stragglers on the old spider, we're going to migrate them over in the next few days. There are still a lot of issues to shake out, as with any new software (for instance, there are still some error recovery scenarios to deal with). But it's getting better all of the time (love that song). We'll be rolling out new tools internally for identifying where improvements are needed, ultimately we'd like to enable bloggers to help themselves to publish, get crawled, be found and recognized more effectively. And there are more changes afoot, stay tuned.

technorati web crawling software spam splogs

Code Is Social

spidaman — Fri, 27 Feb 2009 18:26:15 -0800

Like many software developers, I confess that I have found myself on occasion coming back to old code that I wrote asking, "What was I thinking?" Where it's my code, this WWIT question doesn't happen very often these days but in general I can't count the number of times I've encountered and had to work on code that was not written to be read. I think sometimes programmers write terse code and regard its brevity as a badge of honor, "If I'm wizardly enough to write this, then only True Wizards will read it." Or maybe it's just laziness or hurriedness, these code mysteries are akin to omitting comments, API documentation and other communication artifacts. When I see non-descriptive variable names, gratuitous indirection, excessive right indenting, monkey patching or unnecessary cyclomatic complexity, it's almost anti-social behavior; it's a communication fail more than a functional one. Likewise, gratuitous verbosity stifles communication in the opposite manner; this isn't pre-school - grasp of the ABC's is assumed. So spelling out what code is doing in this belabored fashion is just silly:

# an array to collect permalinks
permalinks = []
# loop over the feed entries
for entry in feed.entries:
    permalinks.append(entry.link)

Whereas this is clear

# extract an array of permalinks from the feed entries
permalinks = [ entry.link for entry in feed.entries ]

OK, I'm assuming the reader knows what a Python list comprehension does. The first one is using a lot of vertical space to satisfy a very simple intent. I often find the opposite problem, excessive brevity, is authored by those enamored with their language's idioms. Software written with scripting languages often exhibit this; Perl is famous for expressiveness (I say this lovingly as a repentant x-Perl Wizard) but even the languages with adherents claiming their tongue is more "readable" have those same users donning wizard hats, trying to be clever. Ever tried to maintain Python code riddled with nested list comprehensions containing lambdas? Ruby, similar idiomatic norms abound, 'nuf said.

I've appreciated celebrations of wizardry (see A folding language) but there's more to wizardry than meta-programming and brevity. Coding like a wizard doesn't mean being so clever that only other wizards can collaborate. In my view, a true wizard has the wisdom to steer clear of verbose indulgences and terse spells; the wizard walks the middle path of clarity so that the code is not dumbed-down but the apprentice will grasp the intent. The wizard's code should read as poetry.

When code is unsocial (or anti-social), the quality suffers. Complex software needs a gene pool - lots of eyeballs, lots of variant perspectives and experiences. A small gene pool leads to in-bred ideas. Thus code from a lone wolf (even a kick-ass wolf) will usually be of lower quality than code developed by a plurality (unless its a plurality of novices, then all bets are off).

My plea to fellow crafters of bits: please code for clarity. Don't be so brief that your intentions are unclear. And don't be so garrulous that your intention is lost in the verbiage. Again, I'm not claiming innocence of these sins of code. But over the years I've become considerably more aware of the costs and benefits in the choices between brevity and verbosity. Perhaps clarity is in the eye of beholder or perhaps more narrowly, in the eye of the author. But I try to look at my own code objectively and ask, "If I don't see this code for six months and then come back to it to do some maintenance, will today's intent be clear?" I hope the code I write will be approachable by those who come behind me to work on it, especially if it's me lest I ask myself the WWIT question.

Sigh, I'm venting because I just got side tracked refactoring some program code (and its single test) that lacked clarity. Thanks for indulging me this far. I'm gonna go listen to some old Social Distortion now, have a great weekend!

programming wizardry perl python ruby

Inbloguration: One Week Later

spidaman — Tue, 27 Jan 2009 12:41:39 -0800

As mentioned last week on the Technorati blog, Technorati was crawling the new White House blog within a day of its launch. Most of the blogosphere doesn't require individual customization in our crawling framework but in some special cases, it must be done. The White House blog is a prime example of why this is so but I'm pleased to report that Technorati's new crawling technology makes what was impossible with our old crawler easy with the new one.

Given the volume of moderation that'd be required, it doesn't surprise me that the posts don't take comments. But there are other more basic blogging practices of concern:

It doesn't have clear feed discovery. There are multiple rel="alternate" elements in the head section of the HTML document.
The permalinks are irregular; the first few were under the blog URL, the rest have been under other paths on the whitehouse.gov site.
The HTML doesn't have any of the common CSS attributes that indicate structural semantics; if I get to vote on this, I'll opt for hAtom

The absence of full content feeds or full content on the front page isn't a problem for Technorati's new crawler; it can crawl the post pages and extract content to index from those.

So how has the blog done in the last week? Well, it emerged in the top 1000 just five days after its inception. Keep an eye on the blog's Technorati blog info page - it's currently ranked 882 (1,876 links from 1440 blogs). Many of the links are to main blog page, citing its existence. But the majority of the links were to the kick-off post (date line reads: "Tuesday, January 20th, 2009 at 12:01 pm") and the inaugural address. Here are the posts and their link counts:

Change has come to WhiteHouse.gov - 619 links from 552 blogs
President Barack Obama's Inaugural Address - 217 links from 194 blogs
A National Day of Renewal and Reconciliation - 146 links from 137 blogs
President Obama delivers Your Weekly Address - 103 links from 97 blogs
Statement released after the President rescinds "Mexico City Policy" - 34 links from 33 blogs
Executive Orders to date - 27 links from 27 blogs
The Whistle Stop Tour - 26 links from 24 blogs
Honoring Dr. King's Legacy and Serving America - 22 links from 20 blogs
From peril to progress - 17 links from 17 blogs
Now Comes Lilly Ledbetter - 15 links from 13 blogs
58 years of Indian democracy - 4 links from 4 blogs
The year of the ox - 3 links from 3 blogs
Timothy Geithner sworn in as Secretary of the Treasury - 3 links from 3 blogs
Press Briefing Highlights - 3 links from 3 blogs
President Obama on the Selection of Kirsten Gillibrand - 2 links from 2 blogs

It's really encouraging to see the White House, specifically Macon Phillips, posting updates about President Obama's policies and political activities. Going forward, I hope to see more consistent publishing practices. For instance, should slug words be separated by underscores or hyphens? Should the proper names in URL slugs be mixed case (e.g. Timothy_Geithner_sworn_in) or down cased (e.g. now-comes-lilly-ledbetter)? It's less important which one but just pick one and stick to it! Also, the White House Blog should use durable URLs for permalinks: there's a posting with the path /blog_post/PressBriefingHighlights/, another with /president-obama-delivers-your-weekly-address - what are they going to use for the next post with highlights from a press briefing or next week's weekly address? If Mr. Phillips needs any further advise on effective blog publishing technology, I'm easy to find and happy to be of service.

whitehouse white house blog blogging blog+technology obama technorati inbloguration

Downturn, what downturn?

spidaman — Thu, 25 Dec 2008 13:20:14 -0800

Just the other day, Data Center Knowledge asked Are Colocation Prices Heading Higher? My immediate reaction was, that's a stupid question: last time VC funding went into hibernation, data center space was suddenly cheap and abundant. The article suggested that companies operating their own data centers will run to the colos as a cost cutting measure. Maybe, but I'm not so sure. Data center migrations can be expensive, risky operations. Methinks that the F500's inclined to undertake a migration would have done so already. The article cited a report emphasizing a shift from capital expenses to operating expenses.

Tier 1 says demand for data center space grew 14 percent over the past 12 months, while supply grew by just 6 percent, "exacerbating an already lopsided supply/demand curve."

However, Tier 1 attributed the demand, "especially, (to) the primacy of the Internet as a vehicle for service and application delivery." With the litany of Techcrunch deadpool reports, I'm finding it difficult to believe that the data center space supply/demand will continue skewing.

Sure, it's not all bad news. Fred Wilson reports that Union Square Ventures will be Investing In Thick and Thin. Acknowledging that, "it is easier to invest in thin times. The difficult business climate starts to separate the wheat from the chaff and the strong companies are revealed." Wilson goes on to say

I don't feel that its possible, or wise, or prudent to attempt to time these (venture investment) cycles.
Our approach is to manage a modest amount of capital (in our case less than $300 million across two active funds) and deploy it at roughly $40 million per year, year in and year out no matter what part of the cycle we are in.
That way we'll be putting out money at the top of the market but also at the bottom of the market and also on the way up and the way down. The valuations we pay will average themselves out and this averaging allows us to invest in the underlying value creation process and not in the market per se.

Yes, the economy is gyrating in pain, but the four horsemen aren't galloping nearby. So take a pill, catch your breath and deal with it: the sun will come out, just don't bother trying to time it too carefully.

Now, there's no shortage of reasons for gloom and doom: mega-ponzi schemes collapsing, banks and real estate combusting, the big 3 in various states of failure, yet BMW North America will raise list prices 0.7%. Before the complete credit breakdown, real estate volume was actually rising in a lot of places (ergo: prices were aligning supply and demand). I was at a William-Sonoma store in Albuquerque the other day, the place was mobbed. My point is that while the economy is retrenching (or the country is rebooting), the detritus will be separated (Wilson's wheat from chaff) and data center space should be cheap and abundant. Everything seems fine to me. At least until the next bubble.

For those of you observing that sort of thing, Merry Christmas!

colocation data centers economy

Another Hadoop-backended Database: CloudBase

spidaman — Tue, 23 Dec 2008 16:02:21 -0800

This post to one of the Hadoop mailing lists caught my eye, Announcing CloudBase-1.1 release. Wait, wasn't Cloudbase the embedded database company that IBM acquired several years back but ended up donating the product to the Apache Software Foundation as Derby? No, not that Cloudbase. This is apparently another project that aims to provide data warehousing on top of Hadoop.

I've been watching the emergence of HBase, Hypertable and most recently the proposed incubation of Facebook's Cassandra with great interest. The first two are modeled from Google's BigTable but all are essentially horizontally scalable column oriented databases. The developers of these systems explicitly steer away having their technologies pegged as relational databases, with the refrain: "We don't do joins." What the CloudBase project aims to do is not model themselves on BigTable but to explicitly support joins between tables built on top of an HDFS cluster. It looks like they've posted extensive documentation and have released a JDBC driver, pretty cool! This is the most interesting database initiative I've seen since GreenPlum announced their support for mapreduce.

Yes, as far as scale-out data analytics, we live in interesting times.

mapreduce hadoop hbase hypertable jdbc cloudbase bigtable derby greenplum

Python SVN Bindings, Trac and mod_python

spidaman — Sun, 21 Dec 2008 14:55:24 -0800

I have some code I want to noodle on outside of work. Since I'm on a holiday break, I'm doing a bit of that (yes, this is what I do for fun, so?). In the past, I had used my own private CVS server for those kinds of things but these days, I could just as well live without CVS. I decided to roll a subversion server into my Apache build (the latest Apache + other modules aren't in the yum repositories for my distro, so I roll my own). While I'm putting a subversion server up, why not trac, too? Heh, that's where things got stuck.

When I installed the subversion dependencies (specifically, neon), I just used vanilla build params. After installing subversion, I was surprised that Trac couldn't access it. It turns out that the litmus test was this:

$ python
Python ...
>>> from svn import core

...it failed miserably. Various recompile efforts seemed to move the problem around. I saw a variety of the symptoms described in the Trac-Subversion integration docs troubleshooting section. The missing gss_delete_sec_context symbol error was apparently the telltale critical one, it originated from neon having been compiled without SSL support. The neon compile config that led to success was

./configure --enable-shared --enable-static --with-ssl=openssl

Then the real key was to completely start over with the subversion compile, not just the swig python bindings.

make clean
./configure \
 --with-berkeley-db=/usr/local/BerkeleyDB.4.7 \
 --prefix=/usr/local \ 
 --with-apxs=/usr/local/httpd2.2.11/bin/apxs \
 --with-apr=/usr/local/apr \
 --with-apr-util=/usr/local/apr
make
make swig-py
make check-swig-py
make install
make install-swig-py
ldconfig

Only then did the litmus test above pass. One of the things about this setup that is kind of a nuisance is that the python bindings didn't get installed into site-packages, therefore mod_python was quite unhappy. Also, trac seemed to want to put its eggs in the root directory. So the Apache server's envvars script has these variables exported to work around those issues

PYTHONPATH=/usr/local/lib/svn-python
LD_LIBRARY_PATH=/usr/local/lib/svn-python/libsvn
PYTHON_EGG_CACHE=/data1/egg_cache

The result (including the requisite httpd.conf tweaks) is a working subversion 1.54 and trac 0.11 setup. It was more fiddling for the evening than I'd hoped for and I'm not sure my foibles and remedies were optimal (clearly, I missed an RTFM somewhere) but I hope this resolution helps at least one reader.

Happy Hannukah and winter solstice!

apache mod_python trac neon subversion swig python

World Leader Reflex Tests

spidaman — Mon, 15 Dec 2008 21:35:52 -0800

Will Chuck-The-Shoe-At-The-World-Leader be an Olympic sport in the years ahead? Since finishing with dinner this evening, I've found no less than three flash games and a compendium of animated GIF satires.

Shoe Attack On President Already Turned Into A Crappy Flash Game (Kotaku)
Sock and Awe
The Bush Game
Iraq Shoe Tosser Guy: The Animated Gifs (Boing Boing)

I bet Jon Stewart is pissed that this had to happen two days before his last show of the year. There's still a month left for more Dubya foibles, cut the vacation short Stewart! In the meantime, keep it safe kids.

shoe toss bush humor

OpenEdge vs. Net Neutrality vs. CDN

spidaman — Sun, 14 Dec 2008 22:52:25 -0800

The Wall Street Journal reported today that Google Wants Its Own Fast Track on the Web, describing it as an example of the decline of support for net neutrality amongst the The Powers That Be (the usual suspects: Google, Yahoo, Microsoft, Amazon). Plenty of deals have been getting struck anyway between TPTB and data carriers (most prominently AT&T + Yahoo DSL) but outright transit preference doesn't seem to be an issue here. What Google appears to be getting into, called OpenEdge, sounds like an arrangement that amounts to co-locating their gear in the major carrier's datacenters. This would move serving capacity closer to the end-users of their services and thereby accelerate the user experience. Since it doesn't concern transit per se, this actually doesn't sound like a net neutrality issue at all, it sounds like another form of datacenter dispersion.

So what exactly is the big deal? All of the TPTB and loads of other online services have content delivery network (CDN) deals. Yahoo, Amazon, Facebook... they all operate or partner with a CDN in some shape or form (full disclosure: I've been working on a CDN evaluation for Technorati). With a CDN, publishers pay specifically to have their content cached at points-of-presence (PoP) around the intertubes that, through some DNS and routing magic, enables web content to get to end-users more quickly. The next step beyond a CDN is to put equipment in the carrier's datacenter. Here's what WSJ said

Google's proposed arrangement with network providers, internally called OpenEdge, would place Google servers directly within the network of the service providers, according to documents reviewed by the Journal. The setup would accelerate Google's service for users. Google has asked the providers it has approached not to talk about the idea, according to people familiar with the plans.
Asked about OpenEdge, Google said only that other companies such as Yahoo and Microsoft could strike similar deals if they desired. But Google's move, if successful, would give it an advantage available to very few.

It seems perfectly logical, actually.

Nonetheless, I am concerned about wavering support for net neutrality. Lawrence Lessig, fresh off of his Big News post concerning setting up shop at Harvard Law School, is quoted as saying

There are good reasons to be able to prioritize traffic. If everyone had to pay the same rates for postal service, than you wouldn't be able to differentiate between sending a greeting card to your grandma versus sending an overnight letter to your lawyer.

But the counter argument says that there's a big difference. Grandma isn't trying to compete with your attorney (at least, not usually). If the big guys are paying more to be faster, who will be able afford to challenge them? The intertubularly rich will get richer, the poor will be stay poor. The TPTB will ensconce themselves as dynastic media walking on paths paved with gold while all of us commoners walk in the gutter.

The dumb pipes should stay dumb. If an internet service wants to operate out of multiple datacenters, lease dedicated pipes to accelerate their inter-datacenter data distribution and peer with the carrier's PoPs proximate to their datacenters, mazel tov. This can be augmented with CDNs. It can even be taken to the next step by directly installing the carrier's datacenters. But at the network exchanges and pipes connecting them, everyone's packets should remain equal.

UPDATE GigaOM posted about a clarification from Google which says that the WSJ was "confused". The hubbub in that article really was misplaced, it's a CDN deal.

google cdn content delivery network net neutrality wall street journal

Cloud Hype, An Amazon Web Services Post-Mortem

spidaman — Wed, 10 Dec 2008 23:53:19 -0800

In the last few years, the scope of Amazon Web Services (AWS) has broadened to cover a range of infrastructure capabilities and has emerged as a game changer. The hype around AWS isn't all wrong, a whole ecosystem of tools and services has developed around AWS that makes the offering compelling. However, the hype isn't all right either. At Technorati, we used AWS this year to develop and put in production a new crawler and a system that produces the web page screenshot thumbnails now seen on search result pages. But now that that chapter is coming to a close, it's time to retrospect.

There's a prevailing myth that using the elasticity of EC2 makes it cheaper to operate than fixed assets. The theory is that by shutting down unneeded infrastructure during the lulls, you're saving money. In a purely fixed infrastructure model, Technorati's data aquisition systems must be provisioned for their maximum utilization capacity threshold. When utilization ebbs, a lot of that infrastructure sits relatively idle. That much is true but the reality is that flexible capacity is only saving money relative to the minimum requirements. So the theory only holds if your variability is high compared to your minimum. That is, if the difference between your minimum and maximum capacity is large or you're not operating a 365/7/24 system but episodically using a lot of infrastructure and then shutting it down. Neither is true for us. The normal operating mode of Technorati's data acquisition systems follows the ebb and flow of the blogosphere, which varies a lot but is always on. The sketch to the left shows the minimum capacity and the variable capacity distinguished.

In response to some of the fallacies posted on an O'Reilly blog the other day (by George Reese), On Why I Don't Like Auto-Scaling in the Cloud, Don MacAskill from SmugMug wrote a really great post yesterday about his SkyNet system, On Why Auto-Scaling in the Cloud Rocks. Don also emphasizes SmugMugs modest requirements for operations staff. In an application with sufficient simplicity and automation around it, it's easy to imagine a 365/7/24 service having meager ops burdens. I think we should surmise that the cost of operating SmugMug with autonomic de/provisioning works because it fits their operating model. I understand Reese's concern, that folks may not do the hard work of really understanding their capacity requirements if they're too coddled by automation. However, that concern comes off as a shill for John Allspaw's capacity planning book (which I'm sure is great, can't wait to read it). Bryan Duxbury from RapLeaf describes their use of AWS and how the numbers work out in his post, Rent or Own: Amazon EC2 vs. Colocation Comparison for Hadoop Clusters. Since the target is to serve a Hadoop infrastructure, AWS must get a thumbs down in their case. Hadoop's performance is impaired by poor rack locality and the latencies of Amazon's I/O systems clearly drags it down. If you're going to be running Hadoop on a continuous basis, use your own racks, with your own switches and your own disk spindles.

At Technorati, we're migrating the crawl infrastructure from AWS to our colo. While I love the flexibility that AWS provides and it's been great using it as a platform to ramp up on , the bottom line is that Technorati has a pre-existing investment in machines, racks and colo infrastructure. As much as I'd like our colo infrastructure to operate with lower labor and communication overhead, running on AWS has amounted to additional costs that we must curtail.

Cloud computing (or utility computing or flex computing or whatever its called) is a game changer. So when do I recommend you use AWS? Ideally: anytime. If your application is architected to expand and contract its footprint with the demands put upon it, provision your minimum capcacity requirements in your colo and use AWS to "burst" when your load demands it. Another case where using AWS is a big win is for a total green field. If you don't have a colo, are still determining the operating charactersics of your applications and need machines provisioned, AWS is an incredible resource. However, I think the flexibility vs. economy imperatives will always lead you to optimize your costs by provisioning your minimum capacity in infrastructure that you own and operate.

There's also another option: instead of buying and operating your own machines and racks, you may be able to optimize costs by renting machines provisioned to your specs in a contract from the services that have established themselves in that market (Rackspace, Server Beach, ServePath, LayeredTech, etc). Ultimately, I'm looking forward to the emergence of a compute market place where the decisions to incur capital expense, rent by the hour or rent under a contract will be easier to traverse.

amazon web services aws cloud computing rapleaf technorati smugmug hadoop oreilly data centers capacity planning

The Solar Decade

spidaman — Tue, 9 Dec 2008 23:55:24 -0800

Ten years ago, you might have been advised that solar energy, while sounding nice, was a bad investment. The installations were failure prone and not cost effective. I don't know if I bought that then, I know of solar panels in San Francisco installed in the 80's that paid for themselves, just slowly. But what we're seeing isn't your father's solar panel. From Google's solar panels to residential rooftops, it seems pretty clear that the Economics of Solar Power Are Looking Brighter. Fast Company is running an article The Solar Industry Gains Ground that sounds a chord that we're hearing a lot of. Solar energy is getting more and more cost effective. What's projected is that the cost of solar power may share up-and-to-the-right properties of Moore's Law. The fabs that make the silicon enabling you to read this may also enable an energy giant leap forward. The Germans have their own "Solar Valley" and their industry projection graph appears pretty Moorish (look at the large yellow area).

The big lift off is 10 years away but the investment that has been made in the area and the advances being made seem to put the benefits close at hand. But the big win, when dependence on fossil fuels are on a clear decline, is at leat 10 and 20 years out. But I think it can happen, I think the solar decade is coming. It should be the coming decade. However, it will require an Apollo-mission like focus from the Obama administration to succeed. And I hope we can make it a reality.

solar energy obama

Good Bye, Perl

spidaman — Mon, 8 Dec 2008 00:01:24 -0800

The other day, I was patching some Perl code. There I was, in the zone, code streaming off of my finger tips. But wait, I was writing Python in the middle of a Perl subroutine. Um. I found the bare word and missing semi-colon errors invoking perl -cw dingleberry.pl amusing. How did that happen?

Truth is, I find myself rarely using Perl anymore. I spent years building applications with Perl. Having made extensive use of mod_perl APIs and various CPAN modules, studied the Talmudic wisdom of Damian Conway, struggled with the double-edged sword of TMTOWTDI and rolled my eyes at the Perl haters for their failure to appreciate the strange poetry that is Perl it'd seem like a safe bet that Perl would remain on my top shelf. A lot of the complaints of Perl haters seem superficial ("ewe, all of those punctuation characters", shaddup). Yet, Perl has been long in the tooth, for a long time. I recall 5 years ago thinking that Perl 6 wasn't too far away (after all, O'Reilly published Perl 6 Essentials in June 2003). I'm sorry, my dear Perl friends, insistence that Perl is Alive rings hollow, now.

I still find it heartening to hear of people doing cool things with Perl. David McLaughlin's uplifting How I learnt to love Perl, waxing on about Moose and other "modern" Perl frameworks (but come on dude, everyone knows that PHP, sucks, heh). Brad Fitzpatrick released Perl for Google App Engine today. But Perl, I'm sorry. It's just too little, too late.

I'm just weary of the difficulties achieving team adherence to disciplined coding practices (or even appreciate why they're especially necessary in the TMTOWTDI world of Perl). The reliance on Wizardry is high with Perl; the path from novice to master requires grasping a wide range of arcana. Is it too much to ask for less magic in favor of easier developer ramp up? Perl's flexibility and expressiveness, it's high virtues, also comprises the generous reel of rope that programmers routinely hang themselves with. On top of idiomatic obscurities are the traps people fall into with dynamic typing and errors that only make themselves evident at runtime. Good testing practices are usually the anecdote to the woes of dynamic typing and and yet writing a good test harness for a Perl project is often a lot of work compared to the amount of work required to write the application code.

I well understand the security that programmers feel using static typing but I'm not saying the static typing is the cure to any ills. The compiler is the most basic test that your code can be understood and it gives your IDE a lotta help. That's great but static typing is also an anchor dragging on your time. From what I can tell, Java is the new C/C++ and Jython, JRuby. Groovy and friends (Scala, Clojure, etc) are the ways that people program the JVM with higher productivity. I'm not saying fornever to Perl (that's a long time). But I am saying Hasta La Vista, for now. I've been quite productive lately with Python (I know Perl friends, heresy!) and plan on pushing ahead with that, as well as with Java and other JVM languages. And where necessary, using Thrift to enable the pieces to work together. Python is certainly not perfect, it's quirks are many, too. But I've seen recent success with collaborative software development with Python that would have been difficult to accomplish with Perl. I'm not trying to stoke any language war at all, I'm just reflecting on how I've drifted from Perl. Amongst people I know and things I've read elsewhere, I'm not the only one. Don't fret, Perl, I'm sure I'll see you around.

perl python java programming

MySQL vs. PostgreSQL (again)

spidaman — Sat, 6 Dec 2008 12:08:20 -0800

If Kevin Burton wanted to draw attention to MySQL's inattention to scalability concerns, it looks like he's succeeded (126 comments on Reddit in the last day and climbing). I totally understand why he feels that the MySQL folks need to be provoked into action. I'll confess to having serious "MySQL fatigue" after years of struggling with InnoDB quirks (we use MySQL extensively at Technorati), stupid query plans and difficult to predict performance inflection points (there's a calculus behind table row count, row width, number of indices, update rate and query rate -- but AFAIK nobody has a reliable formula to predict response times against those variables). Frankly, I was really surprised when Sun acquired MySQL (for such a hefty sum, too), I was expecting them to build up a PostgreSQL-based platform by rolling up acquisitions of Greenplum and Truviso.

Kevin is totally correct that to find solid innovation with MySQL, don't look to the MySQL corporation. Instead, the consultants and third party shops specializing in MySQL are where the action's at (Palomino DB, Percona, Drizzle, etc). It's kinda sad, both Sun and MySQL have at various times been home to hot-beds of innovation. Sun has great people groundbreaking with cloud computing, impressive CPU performance per watt improvements and the Java ecosystem. But as far as MySQL goes, look to the outside practitioners.

Kevin's post update cites the pluggable back-ends that MySQL supports as a feature but I'm not so sure. I don't have any evidence of this but my intuition is that it's exactly this feature that makes the overall stability and performance such a crap-shoot (or sometimes, just outright crap). I'm working on a personal project that uses PostGIS (PostgreSQL + GIS), nothing is live yet so I haven't had to scale it. But I have a good deal of confidence in the platform. Skype and Pandora look like good case studies. The PostgreSQL people have been focused on MVCC concurrency, procedure languages, UDFs and data integrity semantics for years. In those realms, the MySQL people are Johnny-come-slowlies (and buggily). On the other hand, if you want the append-only characteristics of logging to a database, MyISAM and merge tables have performance properties that PostgreSQL just can't match.

Maybe David Duffield will look beyond enterprise app services and acquire, roll-up and market the PostgreSQL platforms that Sun didn't. Combining big data and event data with Greenplum and Truviso as a way to blow some smoke in Larry Ellison's eye, that would be funny (and smart).

postgresql mysql greenplum truviso sun workday postgis

It's Only The Biggest Country In the World

spidaman — Fri, 5 Dec 2008 18:12:19 -0800

Should the confirmed reports that Technorati is banned in China be worn as a badge honor? I understand the Chinese authorities value stability but these kinds of things, treating billions of people like little children that need to be sheltered, will ultimately destabilize them.

We've waited 18 years for Chinese Democracy, isn't that long enough? (sorry, couldn't resist the joke)

Best wishes to the Chinese people. At least most of you.

chinese democracy china censorship technorati guns n roses

Technorati Releases Fixes Some UI Peeves

spidaman — Thu, 4 Dec 2008 18:43:39 -0800

In general, I regard successful user interfaces as the ones that provide the least amount of hunting and astonishment. Noone is delighted when the things they're looking for aren't obvious, the data displayed requires lots of explanation and the paths through an application are click-heavy. In this regard, Technorati was long saddled with a user interface that I regarded as delightless. However, I see that changing now and I'm delighted to see that!

Technorati's front end was released today with a handful of significant improvements. One is a long standing peeve of mine: the tag pages we're conflated with keyword search. That meant that if your post was about the president-elect and you tagged it "obama", your expectation that the the posts aggregated at http://technorati.com/tag/obama would also be tagged "obama" would be disappointed; there would also be a bunch of keyword matches mixed in. That came out of last year's attempt to "simplify" the experience by making keyword search and tag browsing the same thing; which was, in all honesty, a George Bush level failure. Sure there are folks who don't know, "What's this 'tag' thing you're talking about?" But for the folks who do know what the difference is between browsing blog posts grouped by tags and keyword search results, the mix wasn't received as a simplification but as a software defect.

I tagged my post "obama" but all of these other posts aren't tagged "obama", what's going on?

I'm glad we've gone back to keeping search and tags distinct.

The other failed aspect of the prior design was the demotion of the search box. The form input to type in your search was sized down and moved to the right, as if it were a "site search" feature. Yes, we'd like folks to explore our discovery features but the navigation for those features weren't great and the de-emphasis on search was again a source of more puzzlement than anything. The release today puts the search box back where it should be: bigger and right in the middle of the of the top third of the page, yay!

Oh, and earlier today Technorati Media released its Engage platform to beta. This is a major step in opening up the ad market place for the blogosphere.

So far, the feedback I've seen on these releases have been thumbs-up. Check 'em out, there's some more goodies in the works but these things only get better with your feedback. And yes, we know there's still more to do, I'm certainly busy with the backend stuff with our cloud platform, ping systems and crawlers (but did you notice the screenshot thumbnails on the search result and tag pages? I need to shake out the latencies producing and refreshing those). Kudos to Dave White, the front end team and the ad platform team for getting these releases out. Onward and upward!

technorati folksonomy tagging user interface blogging ad platform

Can We Just Call It "Flex Computing"?

spidaman — Wed, 3 Dec 2008 22:44:46 -0800

The moniker "cloud computing" has been overloaded to mean to so many things, it's beginning to mean nothing. When someone refers to it generically, you have to ask them to dismbiguate; which of these are they referring to?

IT infrastructure offered as a services
Hosted application functionality
A virtualized server deployment

InfoWorld wrote What cloud computing really means last spring to help clarify the distinctions but still, I often have to stop folks when the use the C-word just make sure we're talking about the same things.

Examples of the first definition are services like Amazon Web Services (AWS) or GoGrid. They provide metered virtual machines, you pay for what you use and have full access (root) on the machines while you use them. Additional goodies such as load balanced clusters, storage facilities and so forth are part of the deal too. Capacity can be scaled up or down on demand and typically, in very rapid fashion. When Peter Wayner reviewed these guys last summer in InfoWorld, he was enamored with the GUI front ends. Call me old fashioned (or a dyed in the wool geek) but unless they're really saving me a lot of time, I have an aversion to the slick GUI's. For his part, Wayner complained about the AWS command line utilities. Actually, when I use AWS, I use a GUI for an overview of running instances, it's a Firefox plugin (Elasticfox) but what I really like about AWS is programmatic access. Integrating application deployment with command and control functionality is very powerful, my tool of choice is boto, a Python API for AWS.

The second definition refers to hosted application functionality, in years gone by they were referred to as Application Service Providers (ASP). The more modern label is Software as a Service (SaaS). However, these services have to provide more than a console for functionality, they have to provide web service API's that enable them to be integrated into other applications. SalesForce.com was an early leader in this space (remember the red cross-outs, "No Software"), their example and the proliferation of RSS is really want inspired the proliferation of APIs and mashups we see today.

The last definition refers to VMWare, Xen and so forth. By themselves, those aren't really cloud computing in my book. However, you can use them to create your own "private cloud" with tools like Enomaly and Eucalyptus. This is an area of great interest to me.

In his review, Wayner pointed out how very different all of the services are. I don't know why he included Google's App Engine at all in his write-up. Don't misunderstand, GAE is a great service but it more closely resembles an application container than infrastructure services.

I'm imagining IT infrastructure management interfaces coalescing around standards (de-facto ones, not ones fashioned out of IETF meetings). Eucalyptus is a good discussion point. Eucalyptus provides an EC2 "work-alike" interface on top of a Xen virtual server platform. So picture this: if the Rackspaces, ServePaths, Server Beaches and LayeredTechs of this world were to provide a compatible interfaces built on top of Eucalyptus, buying compute power by the hour would become more like buying gasoline. There may be pros and cons to this station or that but fundamentally, if you don't like the pumps at one gas station or the prices are too high, you can go to the gas station across the street. Given compatible interfaces, management of the infrastructure, be it with boto, Elasticfox or using services such as RightScale can be as dynamic as the server deployments in those clouds. Such a compute market place would unleash new rounds of innovation as it eases starting up and scaling online services.

The Eucalyptus folks will be the first to fess up that their project is more academic in nature that industrial strength. However, it is the harbinger of AWS as a standard. Yes, I'm referring to AWS as a standard because of the level of adoption its enjoyed, the comprehensive set of APIs it provides and the rich ecosystem around it. What I foresee is that the first vendor to embrace and commoditize a standard interface for infrastructure management changes the game. The game becomes one of a meta-cloud because computing capacity will be truly fluid, flexibly shrinking and growing with hosted clouds, private clouds and migrating between clouds.

cloud computing saas virtualization aws xen

Social Media Backlash Against Cheaters and Fleshmongers

spidaman — Tue, 2 Dec 2008 23:42:34 -0800

As long as there is any media, pornographers will figure out how use it to purvey their wares. The other week, I mentioned on the Technorati blog that I'd been focusing on some spam scrubbing efforts, including removing porn. Apparently we're not the only social media service taking a look at the bottom line impact of miscreant activities. A few related items of interest percolated recently.

Social network service provider Ning announced their End of the Red Light District. The high infrastructure costs, lack of revenue and administrative burdens (DMCA actions) were among the reasons cited. Sounds very familiar, we get our share of that kind of pointless nonsense at Technorati too.

Today, YouTube posted that they were going to crack down or reduce the visibility of porny videos. YouTube's measures include

Stricter standard for mature content
Demotion of sexually suggestive content and profanity
Improved thumbnails

As expected in these cases, the trolls come out to cry foul. But this isn't about free speech or puritan ethics, the issue more closely resembles the tragedy of the commons. It's really very simple: these parasitic uses consume a lot of resources but bring no benefits to the host and degrade the service for other users.

Also today, Digg Bans Company That Blatantly Sells Diggs was reported by Mashable. Apparently Digg has directed a cease-and-desist at USocial.net's practice of selling diggs.

It seems to be an accepted truism that social media oft demonstrates, All Complex Ecosystems Have Parasites. Yep, I've talked to folks from Six Apart, Wordpress, Tumblr, Twitter and elsewhere. We're all feeling the pains of success. Over the past month at Technorati, we've purged about 80% of the porn that was active in the search index. Sure, we're not spam free yet but the index is getting a lot cleaner.

technorati digg youtube ning porn spam

System Gaming and Its Consequences

spidaman — Mon, 1 Dec 2008 22:40:34 -0800

Technorati's authority metric is based on a real simple concept: the count of the unique set of blogs linking to you in the trailing 180 days constitutes your authority. By its very nature, it's a volatile metric. The top 100 of a few years ago bears little resemblance to the one today. When some folks observe their authority rising, they twitter w00ts of joy; when it's falling they complain bitterly that Technorati is "downgrading" them.

Authority is not a perfect metric (crawl coverage variations, etc) nor the only important measurement of a blog (traffic and comments are other metrics we'd like to measure), however it is one that Technorati has been objectively calculating for years.

What I find surprising is the surprise (or denial) that some people find when they learn there are consequences to gaming the system. On a fairly regular basis, someone comes up with the wholly unoriginal idea, "Hey, add your URL to my list of links, re-post it and urge others to follow suit to make your Technorati authority explode!" Or some variant of a viral link exchanging scheme. Some folks take the news graciously, "Oh, that's not OK? I had no idea. It won't happen again." But some of these folks get downright hostile, as if the blog authority metric is their god given right to game. These are probably the same people who expect appreciation on their home's property value to be a god given right. News flash: it's not. Since it's (apparently for some) not obvious: the attention you garner in the blogosphere and the price someone will pay for your house are driven by market forces. If your authority is dropping, create posts that are link-worthy. There's no shortcut. Blogs engaging in viral linking schemes stand a good chance that indexing will be suspended or the blog removed altogether from Technorati's index.

Use the blogosphere to converse, to entertain, to teach and to learn. We'll do our best to measure it and to build applications with those measurements. If you want to play games, get a Wii.

technorati

Big Is The Problem

spidaman — Sun, 30 Nov 2008 18:05:51 -0800

I usually don't rant about economics but I wasn't shopping on "Black Friday" (nor will I be tomorrow on "Cyber Monday") - I'm trying to figure out how to tighten my belt. How it is that I, someone outside of the real estate, finance and auto industries that are so problem plagued, am getting caught in our economy's downdraft? Well, let's see.

Last January, Business Week raised the question "When is an institution too big too fail?" Until September of this year, the financial industry's downward spiral meandered along, like a persistent flu. There were bank failures but the conventional wisdom seemed to be that this was the market at work, winnowing the weak. The bad news ebbed and flowed: mortgage failures, rising oil prices and the weak dollar were countered by stimulus package checks, housing sales leveling off or even rising (where prices crossed their local tipping points) and vibrant web 2.0 and green enterprises. There had been bank failures this year but it took the evaporation of really Big institutions, Lehman Brothers and Merrill Lynch to put Business Week's question on everyones lips. To free market purists, the answer is obvious: whatever may come, let the failures fail. But the reality is that when an enterprise is so big that its failure disrupts significant portions of the overall national and global economy, whatever may come of its failure won't be good. Everyone suffers and bigness is the problem. When these companies become indispensable institutions, we should be afraid.

It seems for years there's been a breakdown in accountability. Loan originators could resell their loans and write new ones, no harm no foul. Right? But one of the key problems with that system is that the originators don't have any skin in the game. The have a money merry-go-round and whoever is left holding the paper (big institutions and their investors) draws the short straw. It's total madness. To date, all of the bank failures have resulted in consolidation in some form or another. Lehman is absorbed by Barclays. Merrill by BoA (which already absorbed Countrywide). The big are getting bigger as the competitive field shrinks. Ironically, this perpetuates the problem: bigness. What happens when Barclays or BoA start wobbling next? Now we have yet bigger institutions that are again too big to fail.

Among the remedies dismissed by free-market adherents is one of the Federal Government investing, taking an ownership stake in the banking, insurance and auto giants who have exposed themselves to risk that has subsequently blown up in their faces. "The government won't know any better how these companies should be run" goes the admonishment. But as if it isn't clear by now, the executives paid the big bucks to know how they should be run apparently don't either. As Newsweek explains in The Monster That Ate Wall Street - How Credit Default Swaps Became a Timebomb, the financial industry had no shortage of creativity when it came skirting the liquidity requirements imposed on them in the years following the S&L crisis. Is it really such a surprise? Michael Lewis (Liar's Poker, Moneyball) recounts in The End of Wall Streets Boom (Portfolio Magazine / December 2008), there were those calling Bullshit but things were just going too damned well for those alarms to be heeded.

It's unescapably clear now that the old adage applies, "if it's too good to be true, it probably is." Until recently, I thought this was only impacting me with the difficulty I had getting my mortgage. But no, the cavalier rating agencies ("the fox was guarding the hen house"), excessively leveraged financial arrangements and detached accountability have led us down this financial rabbit hole into what some now describe as a death spiral. It's not just a Wall Street problem, it's spillover to Main street has cacaded down Sandhill Road. Here's the ominous and infamous slide deck from Doug Leone and friends at Sequoia Capital:

Sequoia Capital on startups and the economic downturn

View SlideShare presentation or Upload your own. (tags: depression recession)

These slides were cited during Technorati's company meeting last week around the layoffs and salary cuts. That really dropped the dark cloud of what's happening in the broader economy close to home.

As bummed as I am about seeing colleagues depart and seeing my paycheck shrink, I'm actually optimistic about the future. Valuations on real estate seem to be reaching reality: they're hitting thresholds that people can afford with conventional financing. Technology continues to fuel innovation and innovation holds the potential to re-shape markets. Come Inauguration Day, it looks like Obama is coming into office surrounding himself with a team of economic advisors who are committed to preserving free markets but are also not so steeped in ideology that they're paralyzed about how to intervene.

I'm looking forward to this cloud lifting. That's my rant.

economy banking layoffs finance economics obama death spiral venture capital

Getting Past Bad Checksums in MacPorts

spidaman — Sat, 29 Nov 2008 15:10:44 -0800

Back in the 1990's I used FreeBSD fairly extensively. One of my favorite things about the FreeBSD project was the "ports and packages" system for installing libraries and application software. Since Mac OS X is, essentially, BSD with a lot of updated chrome, it's not surprising that there's a well functioning "ports and packages" system for it, MacPorts. While it's not perfect, MacPorts seems to function and dovetail nicely with everything I use my Mac for, more so than Fink. Sure, dpkg/apt-get seems to work OK on Debian, every effort I've encountered to apply that model elsewhere has left me disappointed... anyway, yum seems to work well enough, I don't expect to use Debian again.

Recently I found myself with a port that would not install,

port install postgis

would bomb out:

"Target org.macports.checksum returned: Unable to verify file checksums" postgis

It's not a very helpful error message. After some RTFM ("man port", imagine that), I figured there musta been some cruft in the way, so I did this:

port -d selfupdate
port clean --all postgis
port install postgis

And I'm in business with the latest version of PostGIS. Yes, I coulda installed all of that stuff by hand but MacPorts generally has just what I need in a time-saving way. Note, I do all my MacOS X system administration as root so I'm not typing "sudo" all of the time.

macports freebsd postgresql postgis macosx fink debian yum package management

Redistributing the Karma

spidaman — Fri, 28 Nov 2008 21:28:29 -0800

Since Technorati announced pay cuts for the staff earlier this week, I've been a little worried. The mortgage, an upcoming bat mitzvah (nothing opulent, really), doctor bills... the world won't wait for the economy's doldrums to turn around. I think I'll find ways to to tighten our belts (bag lunches, cancel the gym membership, etc) but if you're currently more fortunate than I am and so inclined, this PayPal Donate button is a way you can help.

If I end up with more than needed, I'll simply donate the excess to a worthy charity.
Thanks!

Topic Clustering Visualized in Library Search

spidaman — Thu, 27 Nov 2008 11:43:13 -0800

Public service announcement: your low-tech dowdy public libraries have slicked up high-tech. The old days of long searches through card catalogs and filling out forms in triplicate are gone. Since moving to the east bay several years ago, I've been impressed with the Contra Costa County Library's online catalog that searches all of the branches in the country, online reservations and inter-branch transfers. One of my favorite features is the visual topic clustering.

When searching for "django", a hub-and-spoke is displayed with related nodes such as "reinhardt" and "guitar" as well as misspell candidates. The search results are pretty good too, the first result is for a Gypsy jazz guitar (Django Reinhardt's signature style) instructional video by the main guy from Hot Club San Francisco (Paul Mehling can often be found gigging here in the east bay at the Left Bank in Pleasant Hill, good stuff). Overall, the selection of books, CD's and videos matching "django" was what I expected.

As fond as I am of Gypsy jazz, I'm also interested in the web application framework written in the Python programming language. Changing my query to "python django" brings up a different visual cluster with some of the same cluster terms ("reinhardt" and "guitar") but adds some new ones "monty", "boa" and "computer". The search results were exactly what I wanted: The Definitive Guide to Django: Web Development Done Right by Adrian Holovaty and Jacob Kaplan-Moss and Sams Teach Yourself Django in 24 Hours by Brad Dayley. I'm planning on using django (the python web app framework) for a project (not work related) and, while the online docs are pretty good, having a book (or two) to refer to is definitely welcomed.

All said, I'm a fan of the search and clustering technology enabled by AquaBrowser that the CCC library is using, it's had me wondering how well it would perform against the more volatile data set flowing through Technorati.

django python programming gypsy jazz search clustering library technorati

Wordpress Security Revisited

spidaman — Wed, 26 Nov 2008 07:09:11 -0800

The incidence of Wordpress compromises I wrote of in the spring is still high but the rate of new infections has dropped considerably. A lot of people learned of their blogs' affliction because they were not getting indexed by Technorati. Props to the folks from Google and the Wordpress team for getting the message out too.

Yesterday's release of Wordpress 2.6.5 doesn't target SQL injection or XML-RPC vulnerabilities, this time it's a cross site scripting vulnerability.

The security issue is an XSS exploit discovered by Jeremias Reith that fortunately only affects IP-based virtual servers running on Apache 2.x. If you are interested only in the security fix, copy wp-includes/feed.php and wp-includes/version.php from the 2.6.5 release package.
2.6.5 contains three other small fixes in addition to the XSS fix. The first prevents accidentally saving post meta information to a revision. The second prevents XML-RPC from fetching incorrect post types. The third adds some user ID sanitization during bulk delete requests. For a list of changed files, consult the full changeset between 2.6.3 and 2.6.5.
read the full post

So jump on it Wordpress users, time to update!

wordpress security technorati blogging

Fifteen Hiccups Of Fame

spidaman — Tue, 25 Nov 2008 14:12:45 -0800

It's been a long time since I've felt hopeful about the outcome of an election. I remember well the civil rights anti-war marches of my childhood. The recent years have felt like a return of profound delusional corruption and polarization that marked the Nixon era. The most peculiar aspect of it is how it came to a head with desperate gasp of Sarah Palin's VP nomination. That the questions about her qualifications were questioned at all demonstrates the height of delusion. While the republican fringe ran to embrace her, those with a brain could only ask "WTF?" and cross party lines. If she had been equipped otherwise between those legs, it would never have happened. It's like reverse sexism, if it had been a man with that background and view points, he would have been laughed out the door as a naive hillbilly. (Yep, I am a reasonably educated urban elitist, so?) Instead, we were treated to tragic comedy in slow mo. The graphic included here is a chart of the blogosphere's mention trajectory for Sarah Palin over the prior 100 days.

The timeline starts off with the igloo phase: practically nobody has heard of her and nobody is talking about her. Then there's the nomination at the republican convention. Followed by interviews, the Tina Fey phenom, the election and ...back to the igloo. So long, Caribou Barbie.

All of the talk about her PR representation, book deals, etc are for naught; she's proven at every opportunity that she has nothing to say that is meaningful and contributing to moving our society forward. Nonetheless, it's amusing to read the conservative bloggers who talk about Sarah Palin as "the future of the republican party." As long as they stick to that meme, they're assuring themselves falling further adrift of where this country is going. Bon voyage, don't let that iceberg hit you in the butt on the way out!

Sarah Palin Election Politics