In this talk, Matthew Skelton (Skelton Thatcher Consulting) explores five practical, tried-and-tested, real-world techniques for improving operability with many kinds of software systems, including cloud, Serverless, on-premise, and IoT. Logging as a live diagnostics vector with sparse event IDs Operational checklists and 'run book dialogue sheets' as a discovery mechanism for teams Endpoint healthchecks as a way to assess runtime dependencies and complexity Correlation IDs beyond simple HTTP calls Lightweight 'User Personas' as drivers for operational dashboards These techniques work very differently with different technologies. For instance, an IoT device has limited storage, processing, and I/O, so generation and shipping of logs and metrics looks very different from the cloud or 'serverless' case. However, the principles - logging as a live diagnostics vector, event IDs for discovery, etc - work remarkably well across very different technologies. From a talk at Agile in the City Bristol 2017 http://agileinthecity.net/2017/bristol/sessions/index.php?session=44

1. Practical Operability
Techniques for Teams
Matthew Skelton
Skelton Thatcher Consulting
skeltonthatcher.com / @SkeltonThatcher
Agile in the City, Bristol 2017, London – 02 Nov 2017

2. Today
What is operability?
Modern logging
Run Book dialogue sheets
Endpoint healthchecks
Correlation IDs
User Personas for dashboards

3. You
Software Developer
Tester / QA
DevOps Engineer
Team Leader
Head of Department

4. Operability:
use modern logging, Run Book
dialogue sheets, endpoint
healthchecks, correlation IDs,
and user personas as
team collaboration techniques

6. About me
Matthew Skelton
@matthewpskelton
Co-founder at
Skelton Thatcher Consulting
skeltonthatcher.com

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

8. Team Guide series
#Operability #BusinessMetrics #Testability #Releasability
skeltonthatcher.com/publications

9. Practical Operability
Techniques for Teams

10. What is operability?

11. Operability
making software work well
in Production

13. Logging with Event IDs

15. logging with Event IDs
reduce time to detect problems
increase team engagement
increase configurability
enhance collaboration
#operability

16. search by
event
Event ID
{Delivered,
InTransit,
Arrived}

17. transaction
trace
Correlation ID
612999958…

18. How many distinct event
types (state transitions)
in your application?

20. represent distinct states

21. enum
Human-readable sets:
unique values, sparse,
immutable
C#, Java, Python, node
(Ruby, PHP, …)

22. Technical
Domain
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,
// ...
}

23. BasketItemAdded = 60001
BasketItemRemoved = 60002

24. log using Event IDs
with a modern
‘structured logging’ library

25. example:
https://github.com/EqualExperts/opslogger
Sean Reilly
@seanjreilly

28. Example: video processing
On-demand processing of TV and
mobile streaming adverts
Ad-agency  TV broadcaster
High throughput
Glitch-free video & audio

29. Storage I/O
Worker Job
Queue
Upload

32. Example: video processing
Discover processing bottlenecks
Trigger alerts via LogEntries /
HostedGraphite
Report on KPIs
Target areas for improvement

33. http://honeycomb.tv/

34. Run Book dialogue sheets

36. Run Book dialogue sheets
Checklists for typical operational
considerations
Team-friendly exploration

37. runbooktemplate.infoRun Book dialogue sheets

38. 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 )
…

39. http://runbooktemplate.info/

40. runbooktemplate.infoRun Book dialogue sheets

41. Endpoint healthchecks

43. 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"

44. endpoint healthchecks
Each component is responsible for
determining its own health and
viability – this is very contextual

45. endpoint healthchecks
Use JSON as a response type –
parsable by both
machines and humans!

47. endpoint healthchecks
For databases and other non-HTTP
components, run a lightweight HTTP
service in front of the component
200 / 500 responses

48. Helper service

49. https://github.com/Lugribossk/simple-dashboard

50. Correlation IDs

52. ‘Unique-ish’ identifier for each request
Passed through downstream layers

53. Unique-ish ID

54. 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)

55. Asynchonous (queues, etc.):
Message Attributes, name:value pair
e.g. "trace-id":"348e1cf8"
AWS SQS: SendMessage() / ReceiveMessage()
Log the Correlation ID if present

56. Example: electronic trading
High speed, low latency
Trading options & derivatives
Connected to stock exchanges
Sub-millisecond timings
> £1 million per day traded

60. Correlations IDs for trading
Evidence for timely operation
Help identify bottlenecks
Target areas for perf tuning
Identify race conditions
Increase operability

61. Example: OpenTracing / PCF
3 tracing elements:
TraceID, SpanID, ParentSpan
"X-B3-TraceId" "X-B3-SpanId"
"X-B3-ParentSpan"

62. Example: OpenTracing / PCF
Always log the TraceID as-is
Log calling SpanID as ParentSpan
Log new SpanID

63. Trace
Span
ParentSpan

64. Lightweight user personas

66. Lightweight user personas:
Ops Engineer
Test Engineer
Build & Deployment Engineer
Service Owner

67. Lightweight user personas:
Consider the User Experience (UX) of
engineers and team members using
and working with the software

68. http://www.keepitusable.com/blog/?tag=alan-cooper

69. https://www.geckoboard.com/blog/visualisation-upgrades-
progressing-towards-a-more-useful-and-beautiful-dashboard/

70. Lightweight user personas:
What data does the User Persona
need visible on a dashboard in order
to make decisions rapidly & safely?

71. Summary

72. Operability
making software work well
in Production

73. logging with Event IDs
use enum-based Event IDs to
explore runtime behaviour
and fault conditions

74. Run Book dialogue sheets
explore and establish
operational requirements as
a team, around a physical
table, together

75. endpoint healthchecks
HTTP 200 / 500 responses to
/status/health call with
JSON details – good for
tools and humans

76. Correlation IDs
trace execution using
correlation IDs:
synchronous (HTTP X-trace-id)
async (SQS MessageAttribute)

77. lightweight user personas
explore the UX and needs of
different roles for rapid
decisions via dashboards

78. Operability
use modern logging, Run Book
dialogue sheets, endpoint
healthchecks, correlation IDs,
and user personas as
team collaboration techniques

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

80. Team Guide series
#Operability #BusinessMetrics #Testability #Releasability
skeltonthatcher.com/publications

81. 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/

82. Questions?
Twitter: @SkeltonThatcher | #operability
email: questions@skeltonthatcher.com

83. thank you
@SkeltonThatcher
skeltonthatcher.com