Always wanted to know more about how cgroups work in Linux, where do they come from and how they shape the way we do containers nowadays? Look no further! In this talk Marc will try to give you a bit of history of cgroups, where the idea comes from (the answer might surprise you) and how cgroups have evolved over time.

1. Yourkernelandyou
HowcgroupsmakecontainerspossibleMarcCluet(@lynxman)

2. How memes can be used for everything!
A good oversight of how cgroups work.
Namespaces in the kernel.
Maybe something else… ¯_( )_/¯
Whatyouwilllearn

3. @lynxman
Co-Founder of Ukon Cherry
Organiser of London DevOps
Organiser of DevSecOpsDays London
Co-organiser of DevOps Exchange Barcelona
Previously DevOps instigator at Rackspace, Trainline,
Canonical, ASOS, DevOpsGroup
Been DevOps’in for way too long… I need a coffee
Likes to swear a lot
WhoamI?

4. We’re hiring! In London :)

5. Not run by Dom… yet :(

6. #NotRunByDom

7. YourKernelandYou

8. Containersarenotnew
1979
Unix v7

9. Containersarenotnew
1979
Unix v7
2000
FreeBSD Jails

10. Containersarenotnew
1979
Unix v7
2004
Solaris Containers
2000
FreeBSD Jails

11. Containersarenotnew
1979
Unix v7
2000
FreeBSD Jails

12. Containersarenotnew
1979
Unix v7
2000
FreeBSD Jails
2006
Cgroups

13. Containersarenotnew
1979
Unix v7
2016
Cgroups v2
2000
FreeBSD Jails

14. Containers-Buildingoncgroups

15. Containers-Buildingoncgroups

16. Containers-Buildingoncgroups

17. Containers-Buildingoncgroups

18. Containers-Buildingoncgroups

19. Containers-Buildingoncgroups

20. Containers-Buildingoncgroups

21. Containers-Buildingoncgroups

22. Containers-Buildingoncgroups

23. Containers-Buildingoncgroups

24. Whatweneedinthekernel

25. Whatweneedinthekernel

26. Whatweneedinthekernel
Isolated
Filesystem

27. Whatweneedinthekernel
Isolated
Filesystem
Isolated
Memory

28. Whatweneedinthekernel
Isolated
Filesystem
Isolated
Memory
Isolated
CPU

29. Whatweneedinthekernel
Isolated
Filesystem
Isolated
Memory
Isolated
CPU
Isolated
Users

30. Whatweneedinthekernel
Isolated
Filesystem
Isolated
Memory
Isolated
CPU
Isolated
Users
Isolated
Network

31. Whatweneedinthekernel
Isolated
Filesystem
Isolated
Memory
Isolated
CPU
Isolated
Users
Isolated
Network
Resource
Limiting

32. Whatweneedinthekernel
Isolated
Filesystem
Isolated
Memory
Isolated
CPU
Isolated
Users
Isolated
Network
Resource
Limiting
Accounting

33. Whatweneedinthekernel
Isolated
Filesystem
Isolated
Memory
Isolated
CPU
Isolated
Users
Isolated
Network
Resource
Limiting
Accounting
NAMESPACES

34. Whatweneedinthekernel

35. Namespaces

36. Namespaces
Mount
(mnt)

37. Namespaces
Mount
(mnt)
UTS

38. Namespaces
Mount
(mnt)
UTS IPC

39. Namespaces
Mount
(mnt)
UTS IPC PID

40. Namespaces
Mount
(mnt)
UTS IPC PID
User

41. Namespaces
Mount
(mnt)
UTS IPC PID
User Cgroup

42. Namespaces
Mount
(mnt)
UTS IPC PID
User Cgroup Time Syslog

43. Namespaces
Mount
(mnt)
UTS IPC PID
User Cgroup Time Syslog

44. Whatiscgroups
Control and accounting
CPU
Memory
I/O
Network
And more…

45. Cgroupsv1
12 Controllers
Isolation per thread

46. Cgroupsv1
12 Controllers
Isolation per thread

47. Cgroupsv1
12 Controllers
Isolation per thread

48. Cgroupsv1
12 Controllers
Isolation per thread

49. Cgroupsversion1.0

50. Cgroupsversion2
Full rewrite!
Isolation per process
Better use of namespaces to avoid leakage
Better atomicity
https://lwn.net/Articles/679786/

51. Cgroupsversion2
Not enabled by default in
most distros
Can live next to v1 and you
can choose to enable/
disable per controller

52. Cgroupsversion2

53. InConclusion
• Cgroups are awesome
• Builds on top of namespaces
• V1 still most used
• Most problems fixed
• Compostable superpowers
• I hate bullet lists

54. InConclusion
• Cgroups are awesome
• Builds on top of namespaces
• V1 still most used
• Most problems fixed
• Compostable superpowers
• I hate bullet lists

55. Questions?
Follow me on Twitter
@lynxman

56. Questions?
Follow me on Twitter
@lynxman