The document discusses Docker and how the company Lenses.io uses it for various purposes like reproducible builds, sharing environments, deploying tools, packaging software, and testing. It addresses whether strict adherence to best practices and patterns is always necessary with Docker or if exceptions can be made in some cases. Several examples are provided of instances where Lenses.io either follows or breaks certain patterns with justification. The document advocates balancing practices with pragmatism and argues that what creates value for customers should take priority over rigid rules.

1. https://lenses.io London, Athens, New York
Docker for business
and how I stopped worrying about antipatterns
Marios Andreopoulos

2. DataOps for
Streaming Data
https://lenses.io

3. ● Background in ECE, System
Administration, DevOps/SRE
● GNU, Linux, Go, Emacs, Free Software,
Open Source, Hacking Lover
● Part of Lenses.io founding team
● Currently working on:
○ DevOps
○ SRE
○ Support
○ Sales Engineering and Customer Relations
Head of Dev & IT Operations
w. bow, horn and mouse ears (2019)

4. Lenses.io
We are doing good!
● About 55 people, around half
based in Greece
● Many clients
● Significant and increasing
revenue

5. Success is a chain of events
Docker is a link on our chain

6. Docker is a tool.
Like a screwdriver or
a… laptop.

7. Sharing our OSS
Tools
We use it for...

9. Creating reproducible
builds
We use it for...

11. Sharing environments
We use it for...

12. Deploying our internal
tools
We use it for...

14. Deploying 3rd party
internal tools
We use it for...

15. Packaging our
software
We use it for...

17. Testing our software
We use it for...

19. Advertising &
Demoing Lenses
We use it for...

21. Marketing
We use it for...

23. And even meetups...
We use it for...

24. What creates business value?

25. What creates value for customers?
For engineers?
For investors?
For bloggers?
For students?
...

26. In this context, do antipatterns matter?

27. They say, that…
If all you have is a hammer,
everything looks like a nail.

28. Maybe strict best practices and patterns,
make our tools look more like hammers?

29. Break the rules if you
can give me a good
excuse

30. Docker is simple to
use, so everyone
should write docker
files
Always enforce practice?
Some questions:
● Are you using the image in
production?
● How many people will use the
image?
● Is someone on your team who
can debug?

31. A container should
only do one thing
Always enforce pattern?
https://github.com/lensesio/fast-data-dev/tree/master/filesy
stem/usr/local/share/landoop/etc/supervisord.templates.d

32. Use exec for the main
container process
Good practice
https://github.com/lensesio/lenses-docker/blob/master/setu
p.sh#L813

33. A container should not
run as root
Enforce pattern?
https://github.com/lensesio/lenses-docker/blob/master/setu
p.sh#L708
https://github.com/lensesio/fast-data-dev/blob/master/filesy
stem/usr/local/share/landoop/etc/supervisord.templates.d/0
2-broker.conf

34. Enforce quality
When you can
https://github.com/lensesio/lenses-docker/blob/master/setu
p.sh#L15

35. Provide debug
capabilities
Good pattern
https://github.com/lensesio/lenses-docker/blob/master/setu
p.sh#L10
https://github.com/lensesio/lenses-docker/blob/master/setu
p.sh#L775
https://github.com/lensesio/lenses-docker/blob/master/setu
p.sh#L779

36. Is the port available?
Pitfall
https://gitlab.com/andmarios/checkport/blob/master/main.g
o
https://github.com/lensesio/fast-data-dev/blob/master/setup
-and-run.sh#L470

37. Can we write to the
file? The volume?
Pitfall
https://github.com/lensesio/lenses-docker/blob/master/Doc
kerfile#L61
https://github.com/lensesio/fast-data-dev/blob/master/setup
-and-run.sh#L164

38. Argue both ways
Good pattern?
https://github.com/lensesio/kafka-topics-ui/pull/135

39. Many dockers? Keep
things consistent
Good practice
https://github.com/lensesio/kafka-topics-ui
https://github.com/lensesio/schema-registry-ui
https://github.com/lensesio/kafka-connect-ui

40. Explicitly add files
(whitelist)
Good practice

41. Many external files?
Keep them under a
directory, use
structure.
Good practice
https://github.com/lensesio/fast-data-dev

42. Keep your user
contracts
Good practice

43. Use multistage builds
Good practice
https://hub.docker.com/repository/registry-1.docker.io/land
oop/fast-data-dev/builds/c2e00a24-5c8a-4649-8758-a3574
327195c
https://github.com/lensesio/fast-data-dev/blob/master/Dock
erfile#L1
https://github.com/lensesio/fast-data-dev/blob/master/Dock
erfile#L321

44. Are slim images
always best?
Good practice?
https://github.com/lensesio/fast-data-dev/blob/master/Dock
erfile#L321
https://github.com/lensesio/lenses-docker/blob/master/Doc
kerfile#L1

45. Always store build
information
Good practice
https://github.com/lensesio/lenses-docker/blob/master/Doc
kerfile#L50
https://github.com/lensesio/fast-data-dev/blob/master/Dock
erfile#L273
https://github.com/lensesio/fast-data-dev/blob/master/Dock
erfile#L428

46. Build on the hub. Use
hooks to gather build
info and create tags
Useful practice
https://github.com/lensesio/lenses-docker/blob/master/hoo
ks/build
https://github.com/lensesio/lenses-docker/blob/master/hoo
ks/post_push

47. Learn bash
Seriously

48. Allow for build args
Good practice
https://github.com/lensesio/fast-data-dev/blob/master/Dock
erfile#L18

49. To expose supervisor
or not?
Pattern or antipattern?
https://github.com/lensesio/fast-data-dev/blob/master/setup
-and-run.sh#L266

50. People love good
entertainment
Creativity is a pattern

51. Follow conventions
Good pattern
https://github.com/lensesio/fast-data-dev/blob/master/filesy
stem/usr/local/share/landoop/config_kafka.sh

52. No uninitialized vars
Good practice
https://github.com/lensesio/fast-data-dev/blob/master/setup
-and-run.sh#L19

53. Mind the JVM
Good practice
https://github.com/lensesio/fast-data-dev/blob/master/setup
-and-run.sh#L140
https://github.com/lensesio/fast-data-dev/blob/master/setup
-and-run.sh#L482

54. Respect the logs
Good practice
https://github.com/lensesio/kafka-connect-ui/blob/master/d
ocker/run.sh#L89

55. Secrets may come in
base64
Pitfall
https://github.com/lensesio/lenses-docker/blob/master/setu
p.sh#L247

56. Print a delayed
message in the
console
Ok, that’s a hack
https://github.com/lensesio/fast-data-dev/blob/lenses/filesy
stem/usr/local/share/landoop/etc/supervisord.templates.d/0
0-delayed-message.conf

57. For developers
expose everything,
like logs
Good practice
https://github.com/lensesio/fast-data-dev/blob/lenses/filesy
stem/usr/local/share/landoop/etc/Caddyfile#L37

58. Provide examples
Good practice
https://github.com/lensesio/lenses-docker

59. Thank you!
https://lenses.io London, Athens, New York

60. https://lenses.io London, Athens, New York
Find us:
● https://lenses.io
● https://github.com/lensesio
● https://hub.docker.com/u/landoop
● https://hub.docker.com/u/lensesio
● https://www.linkedin.com/company/lensesio/
● https://twitter.com/lensesio
● https://launchpass.com/lensesio
We are hiring:
● https://lenses.io/careers/
● I am building a new team with junior and
mid-level support people with a track to
DevOps/SRE.