“Sense Amid Madness, Wit Amidst Folly” (Surface Detail)

After 6 years (and change) of working with REA Group I have decided to resign. It’s mixed sadness and joy, as the place I joined all those years ago, is not the place I’m leaving. That’s good, and that’s also one of the reasons.

I’m moving to a medical genetic interpretation service called myDNA (http://www.mydna.life).  In short, people don’t always respond in the same way to medicines, and some of this is because of our genes.  In some cases we can look at our genetic structure and give additional advice to doctors about prescribing certain medicine.

I think this is pretty cool, and I’m actually going to be working on things that will make life better for people every day.  I’ll also be spending heaps of time working with software development teams directly, pairing with developers and improving their skills. At this stage it looks like I’ll also get to learn C# – which I’m pretty excited about.

One of the things that was important to me was being able to have a balance, and I’ve negotiated that with my new employer.  I’ll be working 4 days a week, giving me a day to pursue my own objectives.

I will be;

  1. Focus on providing mentoring/coaching for Women in Technology. From juniors who want to learn to code, to seniors who want assistance with CVs, with conference talk preparation or just general chatting about the state of the industry. I want to help. I want more women in the industry and I want it to thrive. I have 3 amazing women that I’m mentoring now that are happy to provide feedback should anybody be interested.
  2. Cycling.  Yeah.  A spare day a week to go cycling. Living the dream.  I suspect some of this will be consumed in housework.  I’ve made a deal with Mike Rowe that I’m going to ride the 3 peaks with him next year – so I’m going to need that extra time.
  3. Consulting.  If you’re a corporate, with a lot of money that wants somebody with 30 years of software development experience, team leading experience, AWS experience, privacy/security/cryptography and just general knowledge of the industry to come and give guidance, feel free to contact me and see if we can work out a deal.

From what I can tell, the office small, is open plan (but team sizes, not cattle-yard), and I get my own desk – that I can leave stuff on overnight, and have my monitors and keyboard and chair all set up how I like it.  I can have photos of Jo, and George stuck there, and gaze at them when I’m thinking.

I’m unreasonably happy about these little things, but it shows how much those sorts of things count as part of being a human.

The journey starts again.





On the nature of solitude

I don’t like being by myself as much as I am these days.  It’s something I struggle with quite a bit. I’ve had quite a while to reflect on this topic, and there’s a couple of words that are often used to describe the situation, but they mean quite different things to me.

The first is “alone“. To me, being alone, is to not have physical or mental proximity to other humans. This is relatively rare, and for me is a choice that I make if I decide to isolate myself. I like to be alone at times, and to ride, and to run. They are my favourite things to do alone.

The second is “lonely“. This is a feeling of a lack of connectedness with other humans, and in my case I feel this more strongly without a partner. I’m certainly least lonely at this stage when I have my close buddies over, chilling and talking shit. I feel less lonely when I have George with me.

Those who know me IRL would probably consider me fairly extroverted, and that’s true to some extent. I do enjoy being in groups of humans, and it’s something I’ve become comfortable at. It’s not natural for me by any means, I was taught this by my parents, and something that I’ve worked on in my career. What many people might not understand is that I do like to be alone at times, and to contemplate the vastness during that time. I’ve never really been able to describe it well, but I like to ride (and now run) to the limits of my physical capabilities – and use that so my thoughts become focussed on “the now”.

I’ve done this for years, and really didn’t notice what I was doing until I had a conversation with a Twitter friend about what she gets out of Yoga and the mindfulness aspects of it. I like this alone, it’s active or voluntary alone-ness.

Then I read this;  http://www.brainpickings.org/2014/09/03/how-to-be-alone-school-of-life/

I was impressed by how it seemed to accurately describe my feelings on the matter. The distinct difference between alone-ness and loneliness was laid bare and what was confusing to me (I like to be alone, I don’t like to be lonely) and how the world reacts to the alone-ness. I must say I’ve not really felt any great society pressure about my need to be alone. Probably because it’s hidden behind my physical activities that are considered normal to be performed solo.

Turning the gaze to loneliness it’s a bit harder to reconcile my thoughts and feelings on the emotion. While I’d like to “not care”, I find it very hard – and it’s almost something that I find defining as a human. I’m unsure what other people in similar situations to myself do, or if they feel the same way. I suspect that at at this point some form of substitution of life occurs, where distraction, numbing or soothing becomes commonplace.

Working long hours? Drinking? Drugs? Religion?

Who knows?

Excuse me while I go for a ride and think about it a bit more…

Men will always be mad, and those who think they can cure them are the maddest of all. “

Is software an asset or an expense?

I had a brief conversation on Twitter with Camille Fournier () about costing for projects and development, and this is something that I’d been thinking about (but not writing about) since I was at ANZ bank about 2007 or 2008. Most of it was trying to explain/understand expectations about software development and delivery and “how much effort to put into projects”.

Even though I actually have a commerce degree, I don’t intend this observation to be a strict treatise on the accounting terms “asset costing” and “expense costing” but more about the general expectations set by considering the constructed software as an asset, or an expense.

The basic premise is that in general teams of software developers, in the absence of specific direction or rules will assume that the software being delivered will have the properties of an asset. The software will last for an extended period of time, it will be modified and updated and will not generally have a short defined end of life date.

However, in many cases the teams of people asking for software to be built will not always have the same view, and they may be well asking for systems that are developed in shorter time frames, and have a short defined end-of-life date. This generally is where the difference in expectation on project cost (and time) often comes from. We see this a lot in start-ups, where iterating and responding to new ideas trumps all possible long term benefits. With nothing right now, there is no future for the start-up.

Coupled with this particular problem, there is generally a mismatch between how much effort the demand team expects the supply team will take to construct a solution.

So, what should we do about it?

At REA, I’m starting to help our teams with this, and the first step is to get some greater definition about the expectation of not only what problem the system should help solve (“functional requirements”) but also the scope of what that system should participate in (“non-functional requirements”).

Generally these would be called something like SLA (service level agreements). How many users will it support, what is the uptime? What is the response rates? What are the transaction rates? These are pretty standard non-functional requirements that you’d see in systems descriptions. However, one key part that I’m trying to encourage people to think about is “how long should this last?”.

I think the first part of the problem is trying to get an understanding from the customers about what their goals are. Do they want to create some “disposable software” to solve this problem? Do they think that the solution to this problem should last for a long time and be enhanced over that time? Do they even understand there is a difference to the engineering required to do this?

Now, if we add to this the general trend towards microservices (smaller units of functionality that can be more easily replaced) maybe we are looking at a general shift in the way we write code for systems and how we might wish to think about, and set expectations for system development. Can we really think of software components as “write them to throw away”?

Certainly if we’re looking at treating the components or code like an expense, I think there’s a better chance. I also think that using expense based thinking for “research and discovery” might lead to more opportunities for faster iterating through ideas, knowing the expected use and lifespan of the work performed.

I’d also like to see more input from people who have tried similar ideas. It’s a slice of a topic about “software life-cycle management” that is more deserving of thought that most teams give.

2014 – Random reflections

I get to the end of the year and wonder what happened and then I feel like I didn’t actually do anything much over the year. This time I thought I’d put some effort in to reflect on what I inflicted on the universe for the year.


Starting with the most important part of my life. Life with George was again fantastic. He’s growing up into a wonderful human being. He’s so polite, so kind, so generous and just delightful to be with. I completely miss him when he’s not around. The best thing that happened in 2014 was a re-negotiation of our custody arrangements which gives me 6/14 (6 days out of 14) during the school year, and 7/14 during holidays. A great step forward, maybe 50/50 in the near future.

We have a good relationship. We’re both honest with each other about how we feel, and how we want to be treated. This leads to a few tough conversations at times, but they get easier, and pretty much all disagreements end very fast, and normally with lots of cuddles and “sorry how I behaved” – on both sides of the fence. He’s not the only one that has bad days, and it’s important to me that he knows that just a part of life and dealing with it as a family is crucial.

We have a house that we both love, his school is nice and close and we spend many, many hours a week playing cricket when we’re together. If we’re not off finding some nets, we’re playing keeping in the back yard, or watching it on TV. George loves cricket, and that’s been reflected by his achievements in playing with his new club. He plays in the under -10s, manages an average of about 20, top score of 40 (off 4 overs) and best bowling of 2/1 (off 2 overs). He’s only been dismissed once, and that was an overenthusiastic pull shot that ended up destroying the stumps. Oops. Pretty handy in the field and likes to keep as well. It’s great to see him doing well at something that he enjoys.

He’s going great at school, he works hard and enjoys turning up and doing different things with his friends. He’s a good little man.


Nothing really to report here. Both of us have avoided most of the really terrible coughs and colds, and despite both of our best efforts neither have managed to end up hospitalised for our recreational (mis)adventures. I’m fit and healthy, and after spending 5+ years being completely obsessed about riding bikes I’ve started to broaden my horizons to other activities.

I was finding it harder and harder to get consistently onto the bike looking while also looking after George. I’d need to spend a good 3-4 hours in the hills to get a solid workout, and that just wasn’t possible for much of the time. So after Amy’s Ride this year decided to take a break from riding for a while (to and from work doesn’t count) and in late October/early November started to look at running. Now, I’d not done any serious running for about 20 years when I used to run in 10km fun runs. The good news is that my cardio fitness base is solid, the bad news is that I’m missing a lot of muscle development for running.

At this stage, I’m pleased with my progress, getting to 4:30 min pace for 5km and 5:30 pace for 10km. Only time will tell how the body will handle it, as I’m already noticing a few niggles. Hopefully just related to lack of muscle development in those areas.

From a mental health perspective, I’m probably in as good a shape as I’m likely to ever get. Most of the anxiety and the pretty severe dent my self-worth took during the later parts of the marriage have been repaired. I’m still pretty nervous about what relationships might mean in the future – but I’ll cross that bridge when it happens. Soon, I hope.


This was a really big year for friends. Some moved within Melbourne, some moved to another country (I miss you Rup!) and some had some bad news. The best thing for me was meeting up with friends I’ve known for close to 10 years. I was able to travel to Blizzcon in November and got to hang out for a week with the most awesome group of people from all walks of life. It would be pretty safe to say that I really didn’t want that week to end, with geeking out about computers, gaming and drinking far too many beers.


There were 2 great things about work this year. The first was that REA started their graduate recruitment program, and I got to play a significant part in forming it, and getting the graduates on board and working with them. The second was that we finally managed to fill all the open roles in the Group Architecture team, and I can spend more time working with a team rather than trying to create it.

It’s fascinating working in the role that I have at REA, and it’s always challenging – most of these are people challenges, not technical ones – and I’m constantly left open mouthed at how some people react to change. I’ve blogged about my work a few times this year, I hope to do it a bit more next year.

Personal Achievements

It was a pretty good year on this front. I’ve been working on an open source project for a very long time, it’s almost part of the furniture in my life and I don’t give it much thought. It then pops up at unlikely times to make me re-evaluate what reach my software has had. The software in question is BouncyCastle. A Java cryptographic library.

  • It’s been shipped in over a billion devices as part of the Android operating system in 2014 alone (3bn total)
  • It’s being used by 12m people creating virtual environments in Minecraft
  • It seems that a large book selling and cloud computing company may also be using it for various things internally (unconfirmed)

So, at this stage there’s few people electronically connected that haven’t been directly or indirectly using software that I’ve written. That’s kinda cool and makes me feel pretty good.

I also managed to get back and do some conference speaking. Something I enjoyed doing years ago (pre-George) and thanks to Evan, Beth and the YOW! crew it was a great experience to do it again.


2014 was a good year. Probably one of the best I’ve had in recent memory. I’m feeling more balanced as a person and more comfortable in my role as a parent. I’d like to spend a bit more time on my personal projects as I feel my software skills are deteriorating below where I’d like.

Life is good. I’m very lucky.

You are not your ideas – a strategy to lessen the blow of rejection

Inspired by @dys_morphia on Twitter, I’ve decided to document my strategy for dealing with rejection of ideas. This particular approach came from a discussion with James Ross and Simon Harris many years ago working with on a consulting project.

James, Simon and I were discussing a bunch of ideas about design and implementation. We were thrashing through them thick and fast and each of us were proposing particular solutions which would be then unceremoniously torn apart by the others. To people outside our little gathering it really looked like we were intent on destruction.  Nothing could be further from the truth, as even though the other 2 are mostly wrong about everything and can’t see the genius of my ideas, as the respect for our work and our worth is paramount in these discussions. Few ideas survived the withering attacks, yet none of us felt harm, hurt or lacking in respect from the participants.

After we’d been doing this for a while, we started to reflect on why this is such an “easy” task for the 3 of us to perform, yet it appears to be very stressful for others. We talked a lot about rejection and about how people feel very close affinity to their ideas and proposals, and that rejection (or criticism) of them is like a personal attack.

James made this very clear explanation about how he thinks about ideas, and why Simon and I probably feel the same way – yet others struggle.

He said(*), “Many people hold their ideas close to themselves, their ideas are hugged, like a teddy to the chest, so any attack on the idea is in very close proximity to themselves and attacks hit not only the idea, but the person behind the idea. The idea is precious, there’s not many of them, and each one is special and nurtured and getting new ideas is a hard thing to do”.

This was compared to what we do, “We feel our ideas are like balls. We generate them, we toss them into the ring for people to observe and comment on. They’re cheap and cheerful and colourful and we know there is a bucket of them we can just keep getting new ones from. Sure, some are special and different in their own way, but the ideas are tossed away from our selves, and criticism of the size and colour of the balls are clearly not directed at the person”

I don’t want people to think that James, Simon and I are reckless, or foolhardy, or don’t care about our ideas. There’s often very heated debate about our thoughts, our dreams, our visions (and our fears) when we engage in these conversations. It’s just that we realise that our ideas have a life of their own, and it’s our job to bring them to life – we’re the parent of those ideas. We’re not part of the ideas.

If you’re an aspiring artist, a software designer, a poet, an author – or even just somebody trying to work out where to go for lunch, then consider setting your ideas free – toss them away and give them life of their own. You’ve already done the important work in the communication. You can’t be held responsible for how others react to your ideas, any more than you can be held responsible for other people liking your choice in bikes (even though there is a clear right answer here) and more importantly, by giving life and freedom to the ideas, you’re making it clear of a very important fact, you are not your ideas.

(*) I can’t remember exactly what was said, so I’m going to make up the story to convey the intent.

You say you want a revolution..

“Well, you know. We all want to change the world”

My title on LinkedIn is “Reluctant Architect”. This should not be considered a reflection about how I feel about my job, the company I work at, or the work that I do. It’s more of a reflection about what the rest of the industry thinks of an Architect in the software sense.

Basically, the term has been completely hijacked and the use is completely wrong. For the most part architect in the computing industry is some old white guy who’s completely forgotten anything about software development (if they ever did any) and spends all day writing PowerPoint presentations on choosing WebSphere vs Weblogic. This is then inflicted on the organisation like stone tablets being handed down from the mountain.

I can’t find enough words to describe how much I disagree with the concept, the implementation and the horrors that are perpetrated by organisations that follow this model. It is the ultimate in disempowerment, it actively discourages teams from learning and puts power in the hands of people least capable of using it effectively.

So, while I’ve given a roasting to the way my industry has traditionally handled architecture, how, and what do I do differently?

My background is software development, and I’ve spent a lot of years working with, and mentoring teams, but without a doubt the biggest influence on my recent career has been becoming a parent. I have the most wonderful 8 year old boy, who has the same level of enthusiasm for life as his father along with the youthful confidence that everything he knows is right. At this point, you have to transition from “telling” to “experiencing”. No amount of me telling George that “eating that many lollies will make you feel sick” would convince him. So, short of doing things that would actually (or likely) kill him, I encourage him to safely explore his boundaries. Quite often there is joy in the discovery, and quite often there is cuddles and comforting words after a “learning experience”.

So, being an architect, and a reluctant one at that.

(From dictionary.com) 1550s, from Middle French architecte, from Latin architectus, from Greek arkhitekton “master builder, director of works,” from arkhi- “chief” (see archon) + tekton “builder, carpenter”. An Old English word for it was heahcræftiga “high-crafter.”

This pretty much sums up what I feel about the role in general. I am an old white guy with many scars from building systems the wrong way, or seeing other teams build things the wrong way and I wasn’t quick enough to help them. I try very hard to build relationships with the technical staff across the organisation so I can influence their approaches and thinking without needing to actually tell them “do it this way”. This sounds all a bit unicorn and rainbows and holding hands summer-time walks on the beach, but I’d say there’s very few people at REA that have any doubt about my position on various topics, and what my likely response is if they test those boundaries.

Specifically, what does this look like in practice? Glad you asked! I’ll outline the process that I go through (and have done) at REA focussing on architectural change.

The history

When I joined REA nearly 4 years ago, there was a small number of large applications, there was strong coupling and releases were painful. We were tied strongly to data centres with applications running on racked tin. Applications made many assumptions about how close they were to each other (latency for example). Control of applications were “tier” based (back-end vs front-end) and there was contention across the organisation for product releases.

The strategy

Working with Rich, the main goal was to structure the organisation to allow faster releases and improve the quality of the systems (reduce coupling) to make this possible. There was a heavy investment into cloud computing (using Amazon) as the means to reduce contention in the development and testing area, with still having a pathway to multiple production deployment environments controlled by the business aligned organisational structures (we call them “Lines of Business”)

The vision

A dashboard for each Line of Business that shows all cloud providers in the world, their latencies and suitability for applications, including cost. The teams are able to deploy services across the globe, according to data transfer requirements, latency rules and follow the “cheapest” computing and storage options.


Yeah, something like that, but less Neo and more graphs.

The direction

We need to have our monolithic coupled applications split so that each Line of Business can deploy them independently. Our operational staff need to have visibility into the health of the applications without actually knowing where they are. The systems need to support increased speed of delivery of new function for each of the Lines of Business.

The final attribute is considered one of the driving reasons for these changes – so I’m going to focus on it in future sections. However, at this point most of the work that I do is making sure the technical leaders for the various Lines of Business understand the vision and the direction without interfering too much in the actual implementation.

There’s also a lot more to the ongoing strategy involved, but that’s probably another topic for another time.

The design

I strongly value autonomy and self-discovery by the teams. I think learning by doing is the most powerful approach and Open Source ecosystems have shown that the mutations from different development approaches (generally) improve the state of the art as the development teams learn from previous implementations.

In terms of the design of “the architectural direction and improvements” I’ll explain how I’m influencing the understanding and behaviour around application deployment, modularity and most importantly monitoring and fault tolerance.

I realise that “make application deployment, modularity etc, etc better” isn’t a desirable directive, because it’s not very useful and because in many cases people don’t have a clear idea what “better” is. For developers especially many of these concepts are quite foreign, so what I aim for is smaller fine grained directives that help to provide some gentle prodding for exploration in the right areas.

By doing this, what I’m trying to get teams to “work through” is the potential difficulties involved in implementing some of the architectural improvements in their specific contexts. If I actually knew the answers I’d probably work with the teams directly, but I rarely know “exactly how” teams should implement things. I’m blessed by being surrounded by an awesome group of developers and technical specialists that are very capable of implementing improvements in their own contexts, my role is to show them the path to take.

The implementation

Taking the example of “improve modularity and decoupling”. What is needed under these circumstances is independent services. However, a key part of the total system improvements, especially when relating to multiple independent systems is monitoring and fault tolerance (and investigation). REA Group use AWS for many of our system deployments, so some of this is ‘more important’ than dealing with racked tin, but the same principles should apply.

So, now we think a bit. What can I do at this point, and what principles can I impose on the teams to move in the right direction. One of the most expensive parts of software is the operation of running systems. Most of this is because the monitoring, logging and debugging tools are “left as afterthoughts”. I could say “make sure all systems have monitoring, logging and debugging according to the checklist defined in subsection 42, document 27b-6”. That sort of directive could sound familiar to many people, and is pretty much everything I despise about “enterprise architects”.

My directive was “remove ssh access to all deployed systems, nobody can log in”.

To say the response was incendiary was possibly an understatement. Nomex underwear is standard issue for my job, but it’s very interesting to see how often it’s needed. The other thing that interested me was “what roles gave what responses”.

For the most part, experience ops people (hi Cos, love your work) saw through my facade and knew what was up. They’re also generally used to working in constrained environments, and as a result have a huge toolbox to still effectively do their work. The other good news is that these wonderful people also become great advocates for improvement, because most of the burden of running systems fall in their laps.

Developers are predictably “y u no luv me” because what their main focus is to develop and deploy rapidly, debug issues locally and repeat. There’s probably a good reason for excluding some of these principles during development, but as I will repeat, unless the developers feel the pain themselves, it’s unlikely that changes are going to be made. All that does mean is that the operation team gets sad.

Why did I choose that particular course of action?

Well, it’s pretty controversial, so there’s lots of talk (and complaining) so people communicate with each other about how terribly unreasonable that I am, and how I don’t understand “the reality’ of software development. It’s visible and easy to do (don’t start sshd, easy) and should it turn out to be a retrograde step, it’s easy to change back.

The other benefits we see from this is that our systems start to become immutable – a property that I find particularly valuable in coding, and it transfers nicely to system components as well. This is a great thing in AWS land because we can just shoot the cattle and launch another one, and I know that nobody has been on the box “fixing” it.

By not being able to log into the box, we have to think hard about how we log and monitor our system components, especially important things like tracing transactions through the system. What sort of identifiers? What do our components do under failure conditions, network connections etc

The aftermath

There’s a school of thought that I should carefully explain my reasoning behind my decisions so it’s clear to everybody, and there is limited “heat and light”. There may be some merit to that, but my role is not a dictator, it’s an educator and a communication enabler. I don’t mind if the teams are all plotting to subvert me, or even getting together to bitch about how unreasonable I am, but the point is, they’re talking about it – with each other. That’s a big win. I love watching our internal IRC when somebody proposes “how about I use a bastion box to get to the instances” and there tends to be a few comments like “don’t say that, you’ll make Jon angry”, or “shhhh, don’t say it out loud”. That’s fine. It means that people are paying attention, and that even tongue in cheek comments like that make me feel like a difference is being made.

The second part is that I’m not always sure that I’m right. Sometimes I just go with “this seems like a good idea”. Like parenting with George, provided nobody is going to die (or projects fail spectacularly) then making these sorts of decisions and directions will gain valuable insight into our projects and systems, even if we start to go in the wrong direction.

The astute readers here (well, let’s face it, if you’re reading my blog, you’re probably already astute) will notice that I’ve only described a very thin slice for the implementation. Yes, that’s true. This is a big thing, it’s a long term view and to be honest, it’s sometimes disheartening to have to wait. It’s worth the wait, just need to hold firm and be confident that what you’re doing is the right thing. So don’t be confused that the descriptions above cover all that is needed, even from a pure “this is the direction” point. There’s probably 20-30 separate parts of the implementation that is being influenced at any point in time.

I’m looking for long term change with the work I do. Not short term fixes. I want teams to participate in this journey and not just be told what it looks like. There’s also significant parts of cultural change that form part of what I’m aiming for. People do get stuck “thinking the same way” and it’s my role to try and encourage them to think in a way that systems will be constructed in superior ways.

I hope this turned out to be of value to some people, I’m happy to discuss it further in public, or private emails. I’m very happy to help organisations understand how architecture can be better integrated with the development and operation of systems.

Micro services, what even are they?

This blog post was inspired by Jonathan Ferguson (@jonoabroad on Twitter) where the exchange started.

All the Twitters

@jonoabroad “Does anyone have an agreed term of what micro services is?”
@joneaves “Does it need one?”
@jonoabroad “yes. How is it any different to SOA?”

At this point, 140 characters was just going to make things harder so I suggested I’d respond with a blog post. So here it is.

Firstly, I’m going to start by saying I’ve probably got no right to be leading the charge for a definition for micro services, but I do have a lot of skin in this game, as it’s the direction that I’ve been pushing REA development for the past 2-3 years.  Much of this is my personal perspective, but I do think it’s broadly applicable and does provide what I consider an alternate viewpoint on the vision for micro services that exist. 

To answer Jonathan’s second question “How is it any different to SOA?”, my immediate response is “the intent is different”. With SOA, the intent is a layered architecture of co-operating services where SOA focuses on describing the organisation and co-ordination of the services. With micro services, the intent is to describe the nature of the services themselves and not quite so much the organisation and co-ordination of them.

While SOA is used as a comparison, SOA itself has no “one true definition” but merely a collection of patterns/principles and attributes regarding the organisation and co-ordination between services. I should point out that I see micro services and SOA working well together, with micro services describing attributes of the services themselves and SOA providing useful guidance on how to arrange them.

So, why do I think this way?

I’m a software developer, designer and architect. I like to think a lot about the human factors of software development and how can I put systems in place to encourage development teams to “do the right thing” when building software. There’s far too much shit software out there, and I like to have teams not contribute to that. With that in mind, why did I think micro services was a “good approach”? My definition is meant to be used to guide _development_. The benefits that we get operationally is wonderful – but that’s not the primary reason. It’s to get developers to stop building Borgified software with unclear responsibilities and brittle coupling.

First it’s probably worth providing my definition of what a micro service is, so that there’s at least some context around the discussions that may, or may not ensue. After defining the attributes, I’ll expand on why I consider them important.

Desirable attributes of a micro service is;

  1. The responsibility is narrow. The service does one thing, and one thing well.
  2. The code base is small. The service can be rewritten and redeployed in 2 weeks
  3. There is no 3.

I tried to think of more, but most of them were derived from these. A valuable attribute is the ease of upgrade and redeployment. This is directly related to #1. Another valuable attribute is the ease of change. Both #1 and #2 provide support here. There is also the ability for services to be re-used effectively. This is related to #1.  A person much smarter than I am once said “The unit of reuse is the unit of release”.

There’s possibly some rambly hipster crap about “REST services” and “HATEOAS” but really, that’s such flavour of the month and not really something that I think is that important. Certainly no more interesting than JSON vs XML vs ASN.1. All of these things can be done well, or badly – but don’t provide a defining point on if an implementation has desirable attributes.

The responsibility is narrow

This key point relates to design and the fundamental architectural principles. If the responsibility is narrow, then hopefully it follows that the codebase will be small. If the responsibility is narrow, then the understanding of where to make changes is clearer and design intent can be carried forward. If the responsibility is narrow, then understanding how the service fits in the broader network of services, or how the service can be reused is much clearer.

The second important part here is the ability to release the services often, cheaply and without needing to have a deep graph of dependencies. Having a narrow responsibility means that any systems that want to use the services are only coupled to that service for that responsibility. There’s no undesirable coupling. 

Like object oriented software, services are best with high cohesion and low coupling. Creating services as micro services helps in this regard.

The code base is small

When I first started proposing micro services I wanted to appeal to the developers, so I said that services could be written in any language they choose, The only caveats were that the component had to conform to our monitoring and logging interfaces (to aid with deployment and operations) and that it could be re-written in 2 weeks.

This created significant consternation, not by developers, but by management. They were concerned about the “explosion of software that nobody could understand”. I did laugh while explaining my reasoning. I laughed mostly because their basis of concern was that “it would take too long”. Sadly this shows the lack of understanding about software that pervades our industry.

Most developers are perfectly capable of understanding new syntax, and generally can understand new syntax in a relatively short period of time. What takes much, much longer is understanding twisted and tortured domain logic, scattered across 6 packages and libraries all bundled together in one monolithic application. 

My rationale is that if software is written according to the simple rules (narrow responsibility and small codebase) then the actual language choice is for the most part irrelevant in terms of defect fixing and extension. Sadly, I don’t have a lot of data points in this regard, as developers seem to want to choose the path of least resistance (which is normally keep writing the same old shit in the same way), but I do have a great example written by my team. 

We had the need to write a service and one of the team wrote it in Go. It was working well, performed as expected and when it came to adding some additional monitoring we hit a snag because the Go runtime wasn’t supported by NewRelic. The developer who wrote it had sadly departed the team (I still miss you Eric!) so another team member re-wrote the service and had it redeployed in 2 weeks. Written in Java, using Dropwizard. It was a perfect example of exactly what I was proposing.

There are some really useful patterns that we developed while creating the service, not really suitable for addition here, but if there is enough interest I can expand on it in another post. However, the way we thought about building the initial service and more importantly the automated testing around that service made re-development trivial, and incredibly safe.