A Drift Into Failure

I'm still working towards catching up on my Christmas ready. I already wrote my missives on Thinking in Systems and A Pattern Language; next up is the DevOps favorite Drift into Failure.

The basic premise of Drift is that failures, even massive ones, don't (usually) happen because of a vast conspiracy or from the deeds of evil people. Massive failures occur from behavior that is considered completely normal, even accepted, as part of a daily routine. These routines give our perspectives tunnel vision and often don't allow us to see the underlying issue. Production goals, scarce resources and pressure on performance causes drift in these routines that slowly erode safe practices.

Fatal aircraft crashes and space shuttle disasters are often quoted in the book, however every operations or software engineer in IT has seen this play out a gazillion times before. The site goes down on a regular basis... and no one knows quite why. After digging and pushing new code and re-pushing bug fixes for many sleepless nights, one often finds out that the outage was due to a routine maintenance task gone awry. Maybe a query optimization cache was manually flushed within the production RDBMS, causing the entire cluster to freak out and create a bad query plan. It seemed perfectly sane at the time and even if every single person knew this was going to happen the day before, it likely wouldn't have been caught.

Drift points out how remediation and "root cause" reporting is often fruitless. The concept of high-reliability organizations was pushed in the 1980's as an entire school of thought, focused on errors and incidents as the basic units of failure. Dekker demonstrates that "the past is no good basis for sustaining a belief in future safety," and such a focus on root-cause analysis often does not prevent future incidents. The traditional "Swiss Cheese Model" for determining cause has attempted to see where all of the holes within established safety procedures line up, so as to create a long gap through which problems can drive themselves through. This type of reductionist thinking where atomic failures create linear consequences has turned out not to be predictive after all - instead we need to look at things through the lens of probability.

One of the best practices that anyone, including those supporting enterprise software, can encourage to avoid failure is to be skeptical during the quiet times and always invite in a wide range of viewpoints and opinions. Overconfidence can be your downfall, and dissent is always a healthy way to get new perspective. Dekker quotes Managing the Unexpected to point out that "success... breeds overconfidence in the adequacy of current practices and reduces the acceptance of opposing points of view." Those that were not technically qualified to make decisions often were the ones that made them, or outside pressures (event subtle ones) caused trade-offs in accepted practices. Redundancies that were supposed to make things highly available often make systems more complicated and, in turn, actually make them more likely to fail.

The best way to avoid a drift into failure is to invite outside opinion, even bring in disparate practice groups. Take minority opinions seriously. Don't distill everything to a slideshow. Be wary of adding redundancies and failsafes - often the most simple solution will be the most reliable. The recent re-invigoration in microservices is a great example of this - by simplifying the pieces of a complex system, we can allow each component to work in isolation and ignore the remainder of the system. This allows the system to grow, adapt and evolve without support systems usually provided for monolithic software stacks.

Drifting into failure occurs when an organization can't adapt to an increasingly complex environment. Never settle, always embrace diversity and keep exploring new ways to evolve. A great quote from Dekker is "if you stop exploring, however, and just keep exploiting [by only taking advantage of what you already know], you might miss out on something much better, and your system may become brittle, or less adaptive."

A Systems Language

A Pattern Language is an interesting book to pick up, and that's not just a joke about the size of the volume. Its web site betrays how old the book actually is; it was published in 1977 based on research that had been ongoing for several years. It's scope is pretty large and covers everything from the layout of an office building to the composition of an entire town. Much attention is focused on how to build communities within these spaces, and a lot of research provides evidence on optimal ways of building and tearing down boundaries.

Of particular interest to me were chapters concerning self-governing workshops and offices. The book stresses that no one enjoys their work if they are a cog in a machine. Instead, "work is a form of living, with its own intrinsic rewards; any way of organizing work which is at odds with this idea, which treats work instrumentally, as a means only to other ends, is inhuman." This is a fairly strongly worded assertion that means that employees must feel empowered in order to construct meaningful product.

Just as Thinking in Patterns postulated that groups should autonomously self-organize in order to realize their greatest efficiency, A Pattern Language encourages the formation of self-governing workshops and offices of 5 to 20 workers. A chapter is dedicated to the federation of these workgroups to produce complex artifacts - such as several independent workshops working in concert to build much larger things.

A Pattern Language also encourages keeping service departments small (less than 12 members) and ensuring that they can work without having to fight red tape. This applies to many shared services departments in both government as well as public sector organizations; departments and public services don't work if they are too large as the human qualities vanish. One must fight the urge to make an "idiot-proof system," since this can cause the system to devolve to the point that only idiots will run it.

The book is largely about physical space of course, so it has many recommendations on how offices should be connected. The authors specifically studied what isolated groups within a company, and even what we might consider small physical distances amounted to big interruptions in communication. If two parts of an office are too far apart, people will not move between them as often as they need to. If they are a floor apart, they sometimes will not speak at all.

Ultimately A Pattern Language has a lot of common sense to offer up about how to build a work community, backed by a fair amount of research that bucked many trends in the 70's. It had points that should not be glossed over even now, including:

You spend 8 hours at work - there is no reason it should be any less of a community

Workplaces must not be too scattered, nor too agglomerated, but clustered in groups of 15

Workplaces should be decentralized, not reliant on a central hub

Mix manual jobs, desk jobs, craft jobs, selling, etc. within a community

There should always be a common piece of land (or a courtyard) within the work community which ties offices together

The work community is interlaced with the larger community they operate within

Workspace efficiency and community engagement is definitely not a new practice, however we always tend to think it is. If we can remember the lessons learned thirty-seven years ago, we may be in a better place to make a better workplace today.

Thinking in Patterns

Cognitive Hazard by Arenamontanus

I've finally started to look at some recommended reading that has been on my wish list for going on two years now. Two of the books, Thinking in Systems and A Pattern Language, have particularly resonated with me since they spoke directly to the practice of software engineering without mentioning it once.

Donella Meadows has left behind quite a legacy, and has great observations on how people work within overarching systems. Systems are everywhere and are often composed of yet other systems - just as it is with how people manage their workload every day. In particular, Donella notes the traps that systems can cause which cause things to go completely awry. Let's see if we can identify any of these traps within the context of enterprise software development:

• Policy Resistance (think of "The War on Drugs," where two sides are trying to leverage the same system)
• Tragedy of the Commons (exhausting a shared resource)
• Drift to Low Performance (goals are eroded because negative feedback has more resonance than positive feedback)
• Escalation (one side is attempting to out-produce the other, without a balance in between the two sides)
• Competitive Exclusion (success to the successful)
• Shifting the Burden to the Intervenor (an addiction has removed a system's ability to shoulder its own burdens)
• Rule Beating (finding loopholes)
• Seeking the Wrong Goal

Any of those sound familiar in your current software engineering practice? No matter if this is exhibited between the business and the engineers, or PM's and engineers, or between engineers - these are universal pratfalls.

There are ways to influence systems and avoid the traps we often fall into. These leverage points within the system can allow you to alter behavior and encourage positive results. A tricky point remains that some of the leverage points that are easiest to alter have the smallest impact, and some of the largest impact leverage points are very difficult to manipulate. If we look at an Agile software scrum, you might identify least impactful to most these leverage points as:

1. Numbers, Constants and Parameters. It often feels like you're changing things because you have the most control over these knobs and dials... but all too often reactions are delayed and are cushioned by buffers within the system. Sure, you can change your sprint velocity or begin estimating bugs, but those are just different views on the same result.
2. Buffers, or the sizes of stabilizing stocks that act as reservoirs of results. A buffer may delay or even out the consequence of a change within the system. Changing buffers would be like changing from a two to a four week development sprint in Agile - you may give yourself more time to recover, but more than likely you're just delaying an inevitable fail.
3. Failing that, you might try to alter the real, physical parts of the system and how they interact. This can happen, but they are often difficult to change and result in a game of whack-a-mole. This is more fondly called "re-arranging the chairs on the Titanic," and often is exhibited by swapping out team members but keeping the system the same.
4. The next leverage point might be to try and change how quickly you respond to changes by reducing delays, which in turn alters how quickly the system changes. However, Donella does demonstrate that shorter reaction time can very easily result in greater volatility, and things can become so volatile that they crash. This is what Agile is meant to guard against by locking down a sprint and ensuring priorities aren't changed on a day-by-day basis.
5. In order to get a grasp on things one may also overlook the balancing feedback loops - or safety measures - that safeguard the system in times of emergency. The excuse is generally that "the worst is unlikely to happen," however this drastically reduces one's survival range. Adaptability is important, and if you take away the ability to adapt you can crash even harder.
6. Monitoring for reinforcing feedback loops is something that becomes crucially important. This tasks requires one to watch for runaway chain reactions, which can cause a meltdown if not kept in check. Here bad decisions and bad reactions begat even more bad decisions and bad reactions, causing a runaway system. Look for balance instead of infinite feedback loops; if you can keep pushing your tasks to the next sprint, you're only encouraging a runaway backlog of tasks.
7. Information flows can save a system. If information is in your face and always available, it influences even small decisions. Look at the Nest thermostat or smoke detector - here are devices whose primary purpose is to give you a nonstop flow of info wherever you are. The more info you have (such as how many hours heat was pumped into your house), the more you make small alterations to find balance. This is another part of the Agile process in the form of burndowns/burnups/velocity graphs. This info is meant to be viewed and reflected upon often.
8. Rules (incentives, punishments, constraints) often have to take place to enforce all the above points. In order to kill feedback loops, ensure emergency systems are maintained and information is shared some rules of the game have to be put into place.
9. Self-organization, which is an odd juxtaposition of the above rule about rules, is something that Donella prizes most about not only the human condition but systems in general. Usually if you let the component pieces of a system find their role, they will find a way to work with other components in harmony. This is the proof against micro-management; the more you manage, the more you can threaten a system's success. Let developers go free within the confines of the sprint, and don't hover over them (aside from a daily standup).
10. Find the right goals to change a system. If you focus on GDP, you will focus on gross domestic product at the exclusion of other things. Picking the right goal is tougher than it sounds - you need to know what you want first. However if you can clearly identify and communicate a measurable goal, you can have a huge amount of control over the system. Define what the business actually wants to see - and involve them in the decision making process.
11. Change your mindset. This is effectively what EVERY project management methodology attempts to do - make you think about the same problem in a different way. If it gives you a renewed perspective, this can be helpful. However...
12. ...ultimately you should transcend paradigms and realize no paradigms are true. This is what supposed "anti-patterns" are meant to exhibit, and it can be helpful to realize that Agile, just like Waterfall, will ultimately come and go. Just ship early, and ship often.

Just as we have "Gang of Four" or "Enterprise Integration" patterns, the above are system patterns that can help us decompose and deal with a system. Look for the common traps that always happen - and then evaluate your leverage points to counteract them.

Re-Examining Development Platforms

I've been granted an opportunity for perspective lately. I've done my best to steer away from .NET development up until recently - not because I had any particular gripes, but the technology platform just never seemed to be a great fit. C# as a language is pretty great... delegates, tail closure and nullable references are a welcome respite. VisualStudio isn't bad. If you judge IDEs by how many times they make you swear in a given workday, I'd say my four-letter word tally is comparable to that of me using Eclipse. In fact, once my development environment was up and running I thought I might grow to enjoy .NET development.

And then I started to use the foundation classes. First off... I'll acknowledge that no platform has ever been able to get dates and times "right." This is ever more apparent with .NET... who for some inexplicable reason have no real sense of this "epoch" thing that EVERY OTHER PLATFORM USES. Milliseconds since year zero are expressed as... integers? On top of that, time span arithmetic is only accurate when math is done using "ticks," which themselves are not really accurate to 1/10000 of a millisecond. I didn't go for the caesium clock upgrade in my current laptop.

Java developers often complain that anonymous classes are inelegant or verbose within Java. C# has abandoned anonymous classes in lieu of their delegate-based event handling system. However, C# developers exposed to anonymous inner classes actually seem to like them. A common gripe actually turns out to be a nifty feature when you're talking about event handling. The C#/.NET event handling mechanism isn't that fantastic... it's largely just a loose convention for using delegates. No extras or nice GoF listener patterns provided like a PropertyChangeListener.

Zooming out from design patterns and looking at .NET from an enterprise integration pattern perspective, the .NET platform is definitely at a major disadvantage when compared to JVM-based platforms. I've already covered the state of .NET integration frameworks but to recap: it's still nearly five years behind. My time with EasyNetQ has been great, but I still find myself wishing I could use Apache Camel to construct bigger things using common EIP components.

Despite the current rant, I've been fairly complacent with my new development platform. What really stirred things back up for me was when I cracked open the JMeter-Rabbit-AMQP plugin so that I could do RPC-based load testing of EasyNetQ services. Being a JMeter extension, JMeter-Rabbit-AMQP was a Java app that required me to fire up NetBeans once again and do some Java hacking. Once I did... damn. Until I made that sudden switch back I didn't see the huge gap that existed between .NET and Java development. While C# has some advantage over the Java language, the JVM platform is still leaps ahead.

Once you begin talking about instrumentation the gap grows even wider. I have grown accustomed to the fantastic introspection and profiling offered by Java Management Extensions and VisualVM; by contrast Microsoft's laughable implementation of Performance Counters has caused me more problems than it has solved. If it works (and it often doesn't due to permissions issues or outright registry corruption) there is no instrumentation that allows for live modification of managed objects or details on garbage collection. The actual .NET API to create and maintain performance counters is actually not bad, but the Performance Counter UI is so clunky and ill-conceived that it is often difficult to make use of it.

In the end... it doesn't matter. You do the best you can with the tenured development stack because ultimately it's not about the underlying technology - it's about the squishy, business-logicy brain inside of it. Keeping that squishy brain... err... braining is the most important thing.

Camel Integration

Sweet monkey spit... did I just miss January entirely? Is it seriously February? Dang.

One thing I have been researching lately has been enterprise integration frameworks. I'm a big fan of thinking in patterns while doing design and development and that goes double for architecting systems as well. When I sit down to architect a system I do my best to first think in terms of Enterprise Integration Patterns, then in terms of the Gang of Four's Design Patterns, and then in terms of implementation.

For a current project I've completed the architecture and a good chunk of design, so now I'm looking at implementation. I need to tie together a lot of disparate views to a lot of disparate services, which originally sent me down the path of evaluating Enterprise Service Bus products. I liked the content based routing using Drools utilized by JBoss ESB and ServiceMix. The orchestration of Chainbuilder was also a nice move forward. All had proper integration with naming and directory services as well. Ultimately, however, I found that most of the functionality within an ESB solution simply wouldn't be leveraged; the authentication and authorization model would need to be refactored, I didn't really need transactional support and there was no business process management to speak of.

I really just needed component adapters, translators and content-based routing. Slimming things down to just an integration framework left two main choices: Apache Camel and Spring Integration. Both offered the decoupling I needed and mirrored the Enterprise Integration Patterns I had already used in my architecture layouts. Even though these two frameworks are remarkably different in their implementation they are difficult to contrast. The rumor is that this similar-but-different approach is well known, in that the Camel team originally envisioned becoming a part of Spring. Of course Spring decided to roll their own ultimately to better fit their view and style (especially in a Spring 3.0 world).

Probably the best comparison is provided by actual, concrete examples of event notification on Hendy Irawan's blog: one written with Spring Integration, another with Apache Camel. The examples are written to leverage Spring Remoting, a remote method invocation mechanism not unlike Jini's remoting mechanism. While the examples do have to jump through the hoops of creating a proxy object, the meat of the comparison is in the application context of the two examples. Note that the Spring Integration configuration is a bit more readable and maps more distinctly to an integration pattern layout. The Apache Camel configuration just looks like a standard Spring bean context, however it uses URIs for connecting components rather than using dependency injection to connect them.

Ultimately I like the convention of having endpoints addressable by URIs rather than keeping them as actual bean references. For my tastes this makes things more agnostic (even from Java itself) and more coherent. Having URIs indicate addressable resources is a convention most developers are familiar with, if not just by writing curl scripts.

There are a lot of facets to view when attempting to evaluate integration frameworks and service buses. Gunnar Hillert's blog can give you a small peek into how wide of an ecosystem this really is - you can't just perform a straight-forward SWOT analysis any more. One must always architect first, design second then look at what implementation can get you their with ease and speed.

Designing Head Patterns

When I saw Jason McDonald's design patterns quick reference guide I marked out. I forwarded the link to everyone I knew who heard of the Gang of Four and printed out a nice, one-page color version to keep. I almost freakin' framed it. I liked how succinct it is... it gives you the class diagrams so your brain is instantly sparked, and just enough description that you still have to think analytically about the pattern.

A few people asked me about the original Design Patterns book and a few others mentioned how much they liked Head First Design Patterns. I have to sadly admit - I originally wrote off the Head First series as just another "X for Dummies" clone, but now that I read the RMI section of their Java book and read the first 100 pages of their Design Patterns book I have to admit I judged... sigh... a book by its cover.

The RMI section was actually fairly straight forward and illustrative and even included an informative chapter that included Jini. The Design Patterns book has done a good job of explaining the Decorator pattern, something that I can't do with a pencil and paper in front of someone. Both books have been good references for me to pass along to other developers.

If only there was a pattern to remove outdated cliches two paragraphs ago.