Overview of CoreOS from the point of view of the APIs involved.

2. About Me
CTO/CO-FOUNDER
systems engineer
@brandonphilips
github.com/philips

3. What is CoreOS?

4. What is CoreOS?

7. What is CoreOS?

8. Why build CoreOS?

9. reduce API contracts
minimal

10. kernel
systemd
etcd
ssh
docker
python
java
nginx
mysql
openssl
app
distrodistrodistrodistrodistrodistrodistr

11. python
java
nginx
mysql
openssl
app
distrodistrodistrodistrodistrodistrodistr
kernel
systemd
etcd
ssh
docker

12. python
openssl-A
app1
distrodistrodistrodistrodistrodistrodistr java
openssl-B
app2
java
openssl-B
app3
kernel
systemd
etcd
ssh
docker

13. CoreOS
python
openssl-A
app1
distrodistrodistrodistrodistrodistrodistr java
openssl-B
app2
java
openssl-B
app3

14. CoreOS
container
distrodistrodistrodistrodistrodistrodistr
container
container

15. https://github.com/philips/hacks
folder: system-api-tutorial
APIs

16. Linux syscalls
API

17. manual
updates

18. automatic
updates

19. automatic
updates

20. atomic with rollback
auto updates

23. omaha
API

25. run and isolate apps
containers

26. http
registry
image fetch

27. pid ns
isolated pid 1

28. user ns
isolated uid 0

29. network ns
isolated netdev

30. mount ns
isolated /

31. cgroups
manage resources

32. cgroups
count resources

33. cgroups
limit resources

34. namespaces
API

35. cgroups
API

36. docker engine

37. REST
API

39. dbus
API

40. machines and clusters
configuration

41. get into the cluster
machine conf

42. #cloud-config
ssh_authorized_keys:
- ssh-rsa AAAAB3NzaC1yc2E…
coreos:
etcd:
discovery: https://discovery.etcd.io/ba09c
units:
- name: etcd2.service
command: start
- name: fleet.service
command: start

43. #cloud-config
ssh_authorized_keys:
- ssh-rsa AAAAB3NzaC1yc2E…
coreos:
etcd:
discovery: https://discovery.etcd.io/ba09c
units:
- name: etcd2.service
command: start
- name: fleet.service
command: start

44. #cloud-config
ssh_authorized_keys:
- ssh-rsa AAAAB3NzaC1yc2E…
coreos:
etcd:
discovery: https://discovery.etcd.io/ba09c
units:
- name: etcd2.service
command: start
- name: fleet.service
command: start

45. REST
hypercalls
filesystems
API

46. what is running
cluster conf

47. k8s, discoverd, confd
services

48. what should run
cluster conf

49. locksmith
coordination

50. fleet, k8s
scheduling

51. etcd
API

52. etcd

53. /etc
distributed

54. Available

55. Available

56. Available

57. Unavailable

58. Available
Leader
Follower

59. Leader
Follower
Available

60. Leader
Follower
Temporarily Unavailable

61. Leader
Follower
Available

62. http+json
API

63. getting work to servers
scheduling

64. You
Scheduler API
Scheduler
Machine(s)

65. $ kubectl run-container
my-nginx --image=nginx
--replicas=1 --port=80
$ kubectl get pods
POD IP
my-nginx-97wt8 10.2.29.4

66. http+json
API

67. $ cat nginx.service
[Service]
ExecStart=/usr/bin/rkt
docker://nginx
$ fleetctl start nginx.service
Job nginx.service launched on
e1cd2bcd.../172.17.8.101

68. http+json
API

69. while true {
todo = diff(desState, curState)
schedule(todo)
}

70. while true {
todo = diff(desState, curState)
schedule(todo)
}

71. while true {
todo = diff(desState, curState)
schedule(todo)
}

72. while true {
todo = diff(desState, curState)
schedule(todo)
}

73. the future