Your browser doesn't support the features required by impress.js, so you are presented with a simplified version of this presentation.

For the best experience please use the latest Chrome, Safari or Firefox browser.


Andrew Hatch


Business orgin

Based in Melbourne

Mostly in AWS

Ship a lot

Seek today...


#1 Jobs Site

= 160


Stuff breaks...

...we should expect it to

How we used to do incidents

When we tried to fix things

Where our thinking did not support the complex system we were building

Changing the way we think about systems and people

Building a more supportive incident management process

How we need to think about complex systems in the future


5 x WHY? =


teams worked in islands

operations hated deployments

incidents had some monitoring but many times it would be the customers telling us


About 6 years ago

Knowledge existed almost exclusively in operations and customer support teams

The rest of Seek was largely oblivious, which was more or less how poeple expected it to be

When it came to incident learning


But life is much better now

No more silos, we ship lots of code, we diversify our software

But doing this exposed a critical flaw in how we handle and anticipate failure

Because our software systems evolved to a much more distributed complexity model

In the year 2019

DevOps as a Culture

Our environment became much more complex....

...our ability to adapt and learn from failure did not keep up

But our system is getting complex. Teams produce lots of API's

Those API's have dependencies

Knowledge of incidents is no longer siloed

Handling and anticipation is localised

Systems change frequently, not all performance is expected or predictable.

Handling incidents starts to change



Complexity hasn't gone away....

...we've just moved it

Incident profiles have started to change

And as profiles chnaged it exposed a lack of skill in managing unpredictable and unforseen events

The Black Swan event was about to happen

Increased integration points

+ tight & loose couplings

+ localised decision making

= Emergent Behaviours

January 2017

10K Customers

18 hours of outage

A routine update of Windows DNS caused catastrophic failure in our DataCentre and AWS

It exposed some implemntations of Linux inability to cahce DNS records, sending network traffic flooding from retires and failures

The failure was so widepsread it was impossible to know where all the issues were

It also highlighted how little teams that had been put on support roles knew how to diagnose DNS related issues

one day in May 2017...


12 hours of continuous outage!

Immediately looked at getting more information around incidents

Management had to be seen to be in control of failure

Because failure is often perceived as a lack of control

Safety Incident Management 1.0

Incident Post-mortems

Focused heavily on the root cause

Encouraged to use 5 whys

"How could you not have noticed that?"

"But isn't that the way it should work?""

Hindsight bias

Action items were created. But they were very localised and specific. Underlying systemic problems were not always addressed

Large focus on people failure, conversations were pre-loaded to fail

Safer systems were assumed to attained only from an decrese in incidents - the ones that were known.

Safety can be defined as a state where as few things go wrong as possible - theories developed in the 1960's and 1980's.

Generally systems were simpler, able to be decomposed And the functions of the systems did so in a bimodal manner

Reporting in this way became a process of pushing accountability up not a responsibility down

Weekly Incident Review...


"we don't want this... be too comfortable"




Things still keep going wrong. Even as recently as last month

This is the flipside to DevOps all the Things. Distributing ownership means distributing complexity and variability at the edge

If teams are not guided through the transition nor appreciate the complexities of operational production systems then why are we treating them this way?

...not really

WHy aren't we seeing the system for what it has become. A complex socio-technical system that is in a state of constant variation and change

Why do we spend so much time on what is failing, and not what is going well create an environment that enables us to just do more of that?

Why have we been conditioned to think this way?

What about...

Management of work

People are the unpredictable parts of the system

variance and local adaptation must be neutralised

Management should enforce rules and workers should obey

All functions and associated training are defined in intimate detail, people only act as directed

Frederick Winslow Taylor

The Principles of Scientific Management (1911)






rooted in linear thinking, which is understandable due to the mass industrilaisation of the 20th century.

Incidents followed this pattern. Problems are thought of a chain of events, needing isolation down

More of than not this is the human, the unpredictable, flawed component of the system

Linear Thinking

Chain of events

Isolate down to a single origin of failure

1:1 Cause and Effect

Human Error!


Five Whys

Root Cause Analysis

60 years later...

Modern complexity

RCA and 5 whys may work well for early to mid 20th century manfacturing

But there is a lot greater complexity in the systems we build now

At Seek our AWS Footprint and the number of teams we have number

We may deploy like pipelines but our production systems resemble a decision tree - not an assembly line








API or Event driven

Loose or tightly coupled

Change can be unpredictable

Not all integrations are known!

RCA fails complex system learnings

here is a simple example of why RCA fails in this complex environment and inhibits, learning andcreativity

Root Cause Analysis (RCA), a common practice throughout the software industry, does not provide any value in preventing future incidents in complex software systems. Instead, it reinforces hierarchical structures that confer blame, and this inhibits learning, creativity, and psychological safety.





What are we observing?

Localised management as complexity grows

Evolve independently, do not resemble assembly lines

Expensive, slow, trivialises failure

Incidents are not just about knowing what pressure the system experience

we need to understand the pressure that people go through as well

Environment like before, during and after the incident

Westrum in here about shoot, bury or embrace

What do the teams do well, how do we do more of that

Improving incident learning

Deadline pressure


Communications, etc..







The Post-Mortem

Contributing factors


Contributing factors





Focus areas

Support & assistance

teams think more about balancing reliability with delivery speed

Realising value

Edge Networking


Build Automation

Greater understanding of what our system really is. Complex, sometimes unpredictable.

Things beyond our control and we need to be cool with that

Improved understanding

Complexity does not decrease

Feedback loops can sometimes be unintended

Emergent incidents are a reality

Are the flexible and adaptable parts of the system

We have to trust and support them


And this will lead us to...

Resilience Engineering

It is a Field and a Community

It's not a tool or a product.

It is multi-disciplinary, it crosses multiple industries, has origins dating back several decades but has become more of a "thing" in the past 15 years. In other words there is a lot of academic material, it is highly opinionated and that is great because it provokes great discussion

A resilient system is able effectively to adjust its functioning prior to, during, or following changes and disturbances, so that it can continue to perform as required after a disruption or a major mishap, and in the presence of continuous stresses.

Sustained Adaptive Capacity

It is both a field and a community, with origins in multiple disciplines

It is what your organisation does. Not what it has.

Understanding Resiliency

Not a tool, not a prescribed methodology or process, or management consulting SOW

It is about seeing people and systems together, their interactiosn and feedback loops, complexity as emergence

Natural world. Gum tree, cope with fire, flood, drought. But not emergent threats such as extremem climate change, or a chainsaw!

We can't afford to wait 100,000 years though, as systems get more complex we have to adapt and learn faster

Then leading change by focusing on what is done well, further driving a learning culture

When done well it will enable greater adaptation to market forces and challenges

I don;t profess to be an expert: Here is one of the best places to start reading:

The natural world has plenty of examples

Australian Gum Tree




Unforseen event!!!

But not emergent threats such as extremem climate change, or a chainsaw!

We can't afford to wait 100,000 years though, as systems get more complex we have to adapt and learn faster

Then leading change by focusing on what is done well, further driving a learning culture

When done well it will enable greater adaptation to market forces and challenges

I don;t profess to be an expert: Here is one of the best places to start reading:

You can't wait for resilience to evolve naturally.
It must become an on-going practice

Create conditions and environments where teams can sustain adaptive capacity - wherever the work-is-done

Learn from incidents as much as possible
They are normal by-products of building complex systems. Use them.

Seek to understand the intimate interactions between people and technology.
Don't isolate them as separate challenges

Learn from Safety-2 thinking. Focus and promote what you do well. Sustain and grow the learning culture

Thank you