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Practical Operability
Techniques for Teams
Matthew Skelton
Conflux
confluxdigital.net / @ConfluxHQ
Continuous Lifecycle London, 17 May 2018

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Practical operability
Why do we need a focus on
operability?
5 practical operability
techniques to try
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3.
use modern logging, Run Book
dialogue sheets, endpoint
healthchecks, correlation IDs,
and user personas as
team collaboration techniques
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About me
Matthew Skelton, Conflux
@matthewpskelton
matthewskelton.net
Leeds, UK
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assemblyconf.com

5.
Team Guide to
Software Operability
Matthew Skelton & Rob Thatcher
skeltonthatcher.com/publications
Download a free sample chapter
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6.
You?
Software Developer
Tester / QA
DevOps Engineer
Team Leader
Head of Department
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Practical
Operability Techniques
for Teams
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Operability
making software work well
in Production
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Operability
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“But can’t we just give
those things to a DevOp?”
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“But can’t we just give
those things to the
DevOp?”
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Operability is
a shared concern
#BizDevTestSecOps
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Operability is
a shared concern
#BizDevTestSecOps
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A self-managed Kubernetes
cluster near you

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Operability is
a shared concern
#BizDevTestSecOps
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Practical operability techniques
1. Modern logging
2. Run Book dialogue sheets
3. Endpoint healthchecks
4. Correlation IDs
5. Lightweight User Personas
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Lack of observability for
distributed systems
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Logging with Event IDs

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Modern logging w/ Event IDs
Distinct application states
No “logorrhoea” (!)
Distributed tracing via logs
Build a shared understanding
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search by event
Event ID
{Delivered,
InTransit,
Arrived}
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transaction
trace
Correlation ID
612999958…
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How many distinct event
types (state transitions) in
your application?
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represent distinct states
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enum
Human-readable sets:
unique values, sparse,
immutable
C#, Java, Python, node
(Ruby, PHP, …)
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public enum EventID
{
// Badly-initialised logging data
NotSet = 0,
// An unrecognised event has occurred
UnexpectedError = 10000,
ApplicationStarted = 20000,
ApplicationShutdownNoticeReceived = 20001,
MessageQueued = 40000,
MessagePeeked = 40001,
BasketItemAdded = 60001,
BasketItemRemoved = 60002,
CreditCardDetailsSubmitted = 70001,
// ...
} 27

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BasketItemAdded = 60001
BasketItemRemoved = 60002
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log using Event IDs
with a modern
‘structured logging’ library
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example:
https://github.com/EqualExperts/opslogger
Sean Reilly
@seanjreilly 30

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Example: video processing
On-demand processing of TV and
mobile streaming adverts
Ad-agency → TV broadcaster
High throughput
Glitch-free video & audio
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Storage I/O
Worker Job
Queue
Upload
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Example: video processing
Discover processing bottlenecks
Trigger alerts
Report on KPIs
Target areas for improvement
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Modern logging w/ Event IDs
reduce time to detect problems
increase team engagement
increase configurability
enhance collaboration
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Modern Logging:
Collaborate on Event IDs
and Correlation traces for
better system awareness
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Operational aspects not
addressed, or addressed
too late in the cycle
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Run Book dialogue sheets

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Run Book dialogue sheets
Checklists for typical
operational considerations
Team-friendly exploration
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runbooktemplate.infoRun Book dialogue sheets
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System characteristics
Hours of operation
During what hours does the service or system actually need to operate? Can portions or features of the
system be unavailable at times if needed?
Hours of operation - core features
(e.g. 03:00-01:00 GMT+0)
Hours of operation - secondary features
(e.g. 07:00-23:00 GMT+0)
Data and processing flows
How and where does data flow through the system? What controls or triggers data flows?
(e.g. mobile requests / scheduled batch jobs / inbound IoT sensor data )
… 42

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http://runbooktemplate.info/
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runbooktemplate.infoRun Book dialogue sheets
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Run Book dialogue sheets
Early discovery of
operational requirements
Input to team backlog
“Shift-left” testing
Avoid operational problems
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Run Book dialogue sheets:
Collaborate on operational
requirements for better
system awareness
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“Why has my deployment
failed again?”
“Why is Pre-Prod always
so flaky?”
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Endpoint healthchecks

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Endpoint healthchecks
Simple HTTP check
Common way to assess any
service/app/component
Key operational requirement
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endpoint healthchecks
Every runnable app/service/daemon
exposes /status/health
An HTTP GET to the endpoint returns:
200 – "I am healthy"
500 – "I am sick"
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endpoint healthchecks
Each component is responsible for
determining its own health and
viability – this is very contextual
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endpoint healthchecks
Use JSON as a response type –
parsable by both
machines and humans!
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endpoint healthchecks
For databases and other non-HTTP
components, run a lightweight HTTP
service in front of the component
200 / 500 responses
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Helper service
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https://github.com/Lugribossk/simple-dashboard
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Question:
What does this look like for
Serverless?
¯_(ツ)_/¯

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Endpoint healthchecks
Rapid dashboarding and
diagnosis
Reduce confusion around
environment state
“Fail fast” aka “learn sooner”
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Endpoint healthchecks:
Collaborate on component
health status for better
system awareness
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“Which containers
[servers] handled the
request?”
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Correlation IDs

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Correlation IDs
Unique-ish identifiers
Trace calls across machine &
container boundaries
Re-assemble HTTP
request/response later
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‘Unique-ish’ identifier for each request
Passed through downstream layers
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Unique-ish ID
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Synchronous HTTP:
X-HEADER e.g. X-trace-id
X-trace-id: 348e1cf8
If header is present, pass it on
(Yes, RFC6648, but this is internal only)
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Asynchonous (queues, etc.):
Message Attributes, name:value pair
e.g. "trace-id":"348e1cf8"
AWS SQS: SendMessage() / ReceiveMessage()
Log the Correlation ID if present
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Example: OpenTracing / PCF
3 tracing elements:
TraceID, SpanID, ParentSpan
"X-B3-TraceId" "X-B3-SpanId"
"X-B3-ParentSpan"
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Example: OpenTracing / PCF
Always log the TraceID as-is
Log calling SpanID as ParentSpan
Log new SpanID
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Trace
Span
ParentSpan
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Correlation IDs
Detect bottlenecks and
unexpected interactions
Increase transparency
Learn about the system
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Correlation IDs:
Collaborate on distributed
tracing for better system
awareness
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Software is difficult to
operate: poor UX for Ops.
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Lightweight user personas

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Lightweight User Personas
Simple characterisation of
user needs for Dev/Test/Ops
Based on full UX user
personas but less detailed
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Lightweight user personas:
Ops Engineer
Test Engineer
Build & Deployment Engineer
Service Owner
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Lightweight user personas:
Consider the User Experience (UX) of
engineers and team members using
and working with the software
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http://www.keepitusable.com/blog/?tag=alan-cooper
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Motivations
Goals
Frustrations

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Lightweight user personas:
What data does the User Persona need
visible on a dashboard in order to
make decisions rapidly & safely?
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https://www.geckoboard.com/blog/visualisation-upgrades-progressing-towards-a-more-useful-and-beautiful-dashboard/ 79

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Lightweight User Personas
Empathise better with people
from other roles
Capture missing operational
requirements
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Lightweight User Personas:
Collaborate on user needs
for better
system awareness
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Summary
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Operability
making software work well
in Production
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Lack of observability
Operational aspects not known
“Why has deployment failed?”
What handled the request?
Poor UX for Ops
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Logging with Event IDs
use enum-based Event IDs to
explore runtime behaviour and
fault conditions
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Run Book dialogue sheets
explore and establish
operational requirements as a
team, around a physical table,
together
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Endpoint healthchecks
HTTP 200 / 500 responses to
/status/health call with JSON
details – good for tools and
humans
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Correlation IDs
trace execution using
correlation IDs:
synchronous (HTTP X-trace-id)
async (SQS MessageAttribute)
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Lightweight user personas
explore the UX and needs of
different roles for rapid
decisions via dashboards
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use modern logging, Run Book
dialogue sheets, endpoint
healthchecks, correlation IDs,
and user personas as
team collaboration techniques
91

92.
Team Guide to
Software Operability
Matthew Skelton & Rob Thatcher
skeltonthatcher.com/publications
Download a free sample chapter
92

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Resources
•Team Guide to Software Operability by Matthew
Skelton and Rob Thatcher (Skelton Thatcher
Publications, 2016) http://operabilitybook.com/
•Run Book template & Run Book dialogue sheets
http://runbooktemplate.info/
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thank you
@ConfluxHQ
confluxdigital.net