The ModCloth Platform team has been building a Docker-based continuous delivery pipeline. This presentation discusses that project and how we build containers at ModCloth. The topics include what goes into our containers; how to optimize builds to use the Docker build cache effectively; useful development workflows (including using fig); and the key decision to treat containers as processes instead of mini-vms. This presentation will also discuss (and demo!) the workflow we’ve adopted for building containers and how we’ve integrated container builds with our CI.

1. doing the old thing the new way
by @rafecolton

2. brief prologue
“rafe” (rafecolton on the internets)
software engineer, platform @ modcloth
using docker in prod since v0.7.0
*todo: explain “doing the old thing the new way”

3. obligatory slide with a bunch of logos

4. the stack that was

5. the stack that was

6. the stack that was

7. the stack that would be

8. motivations
• simplify application architecture
• support a variety of application languages
• make provisioning and deployment more accessible

9. motivations
• simplify application architecture
• support a variety of application languages
• make provisioning and deployment more accessible
goals
• push-button provisioning and deployment
• consolidated, pluggable platform
• move to linux

10. motivations
• simplify application architecture
• support a variety of application languages
• make provisioning and deployment more accessible
goals
• push-button provisioning and deployment
• consolidated, pluggable platform
• move to linux
bonus points
• chatops
• actual button for provisioning and deployment

11. motivations
goals
bonus points
• chatops
• actual button for provisioning and deployment
does docker
facilitate such a
solution?
• simplify application architecture
• support a variety of application languages
• make provisioning and deployment more accessible
• push-button provisioning and deployment
• consolidated, pluggable platform
• move to linux

12. the stack that would be

13. case study: modcloth.com/style-gallery
Clear and Simple Statement.

14. case study: modcloth.com/style-gallery

15. case study: modcloth.com/style-gallery

16. case study: modcloth.com/style-gallery
webserver
nginx ruby
smartos
rails

17. case study: modcloth.com/style-gallery
webserver sidekiq workers
nginx ruby
smartos
rails
cron ruby
smartos
rails

18. case study: modcloth.com/style-gallery
webserver
nginx ruby
smartos
rails
sidekiq workers
cron ruby
smartos
rails
how complex could
it be?

19. case study: modcloth.com/style-gallery
webserver
rails
ruby nginx
docker
ubuntu

20. case study: modcloth.com/style-gallery
webserver
rails
ruby nginx
docker
ubuntu
cron

21. case study: modcloth.com/style-gallery
webserver
rails
ruby nginx
docker
ubuntu
cron
supervisord

22. case study: modcloth.com/style-gallery
webserver
rails
ruby nginx
docker
ubuntu
cron
supervisord
sidekiq
workers
rails

23. case study: modcloth.com/style-gallery
webserver
rails
ruby nginx
cron
supervisord
docker
ubuntu
sidekiq
workers
rails
nad
nodejs rsyslogd
sshd

24. challenges
• overall complexity
• maintainability
• image consistency
• container reliability
• log aggregation
• monitoring

25. challenges
• overall complexity
• maintainability
• image consistency
• container reliability
• log aggregation
• monitoring
lessons
• don’t do the new thing the old way
• consider division of responsibility

26. case study: modcloth.com/style-gallery
webserver
rails
ruby
rails
docker cron
ubuntu
nginx
sidekiq workers
ruby
nad
nodejs rsyslogd

27. the stack

28. observations
docker is an excellent packaging and distribution system

29. observations
docker is an excellent packaging and distribution system
containers are the canonical building block for a continuous delivery pipeline

30. begin github search…
projects for orchestrating containers:
• docker/fig
• deis/deis
• flynn/flynn
• coreos/fleet
• ansible/ansible
• opscode/chef
• progrium/dokku
• newrelic/centurion

31. begin github search…
• docker/fig
• deis/deis
• flynn/flynn
• coreos/fleet
• ansible/ansible
• opscode/chef
• progrium/dokku
• newrelic/centurion
• mesosphere/marathon
• airbnb/chronos
• GoogleCloudPlatform/kubernetes
• openshift/geard
• VoltFramework/volt
projects for orchestrating containers:

32. • docker/fig
• deis/deis
• flynn/flynn
• coreos/fleet
• ansible/ansible
• opscode/chef
• progrium/dokku
• newrelic/centurion
• mesosphere/marathon
• airbnb/chronos
• GoogleCloudPlatform/kubernetes
• openshift/geard
• VoltFramework/volt
• octohost/octohost
• makeusabrew/decking
• signalfuse/maestro-ng
• shipyard/shipyard
• DevTable/gantryd
• mcuadros/dockership
• longshoreman/longshoreman
• marmelab/gaudi
• etc.
begin github search…
projects for orchestrating containers:

33. begin github search…
projects for building containers:
• rafecolton/docker-builder
• mitchellh/packer
• swipely/dockly
• ???

34. observation
everybody is building containers differently.

35. observation
everybody is building containers differently.
how do we build production-ready containers?

36. writing a good Dockerfile
lesson 0: getting started

37. writing a good Dockerfile
lesson 0: getting started use a docker hub base

38. writing a good Dockerfile
lesson 0: getting started
set your env

39. writing a good Dockerfile
lesson 1: order matters
deps before bundling

40. writing a good Dockerfile
lesson 1: order matters
ADD only Gemfile* first

41. writing a good Dockerfile
lesson 1: order matters
`ADD .` as late as possible

42. writing a good Dockerfile
lesson 2: optimize for size, repeatability
combine RUN commands
whenever possible

43. writing a good Dockerfile
lesson 2: optimize for size, repeatability
RUN dependent
steps together

44. writing a good Dockerfile
lesson 3: use a standard entrypoint
use a *simple*
entrypoint script

45. writing a good Dockerfile
lesson 3: use a standard entrypoint
operate on docker-specific
environment variables

46. writing a good Dockerfile
lesson 3: use a standard entrypoint
wrap verbose
CMD options

47. writing a good Dockerfile
lesson 3: use a standard entrypoint
exec "$@" # give yourself a shell

48. the image development lifecycle
build
*type things* push
tag

49. the image development lifecycle
push
> docker build -t myapp:latest .
> export latest="$(docker images | grep myapp:latest | head -n 1 | awk '{print $3}’)"
> docker tag $latest "$(git rev-parse -q HEAD)" # sha
> docker tag $latest "$(git describe --always --dirty --tags)" # tag
> docker tag $latest "$(git rev-parse -q --abbrev-ref HEAD)" # branch
> for image in $(docker images | grep myapp | awk '{print $1 ":" $2}' | head -n 4) ;
build
tag
do docker push $image ; done
*type things*

50. the image development lifecycle: docker-builder
push
build
tag
> docker-builder build .
*type things*

51. teh pipeline
docker build
server*
app
app
app
app
*https://github.com/rafecolton/docker-builder

52. conclusion
building containers is like writing ruby code:

53. conclusion
building containers is like writing ruby code:
it’s easy to do
it’s hard to do correctly

54. so what did we learn? (or, through what did you sleep?)
stuff:
• the complexity will come naturally (so don’t force it)
• be intentional about your Dockerfile

55. so what did we learn? (or, through what did you sleep?)
stuff:
• the complexity will come naturally (so don’t force it)
• be intentional about your Dockerfile
• docker is an excellent packaging and distribution system
• containers are the canonical building blocks

56. so what did we learn? (or, through what did you sleep?)
stuff:
• the complexity will come naturally (so don’t force it)
• be intentional about your Dockerfile
• docker is an excellent packaging and distribution system
• containers are the canonical building blocks
• consider division of responsibility between the host and the container
• don’t do the new thing the old way (do the old thing the new way!)

57. brief epilogue
goal: move to linux
=> all apps (less one) now employing docker/ansible/linux

58. brief epilogue
goal: move to linux
=> all apps (less one) now employing docker/ansible/linux
goal: consolidated, pluggable platform
=> shared monitoring, log aggregation, & load balancing services

59. brief epilogue
goal: move to linux
=> all apps (less one) now employing docker/ansible/linux
goal: consolidated, pluggable platform
=> shared monitoring, log aggregation, & load balancing services
goal: push-button provisioning and deployment
=> it works, minimal magic… and it’s well documented

60. brief epilogue
goal: move to linux
=> all apps (less one) now employing docker/ansible/linux
goal: consolidated, pluggable platform
=> shared monitoring, log aggregation, & load balancing services
goal: push-button provisioning and deployment
=> it works, minimal magic… and it’s well documented
could easily be maintained by only two people… dun dun dun

61. brief epilogue
I’m job hunting…

62. brief epilogue
I’m job hunting…
…and I haven’t shot anything yet.
so if you’re hiring, come talk to me after the show.
twitter: @rafecolton
github: rafecolton
rafecolton.com

63. thank you