Kubernetes provides rock-solid APIs for building and running your distributed systems. Pods, Services and ReplicationControllers provide trustworthy and scalable abstractions that make solving real-world infrastructure problems simpler. But that doesn’t mean interacting with those low-level primitives will be the only option for developers and operators. Sched Link: http://sched.co/67dA

1. Kubernetes and the Potential
for Higher Level Interfaces
Puppet Labs
Gareth Rushgrove
Ecosystems, APIs and user needs

2. Gareth Rushgrove
@garethr

3. Gareth Rushgrove

4. Human and computer interfaces
Concepts and demos
Ecosystems and interoperability
Gareth Rushgrove
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5. The User Interface(s)
of Kubernetes
What do we mean by user and interface?

6. The user context matters
Gareth Rushgrove

7. Creating
Consuming
Gareth Rushgrove
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8. Developers
Operators
Gareth Rushgrove
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9. Building something new
Running in production
Gareth Rushgrove
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10. Team size
Regulation/compliance
Multi-tenancy
Infrastructure size
Skills and experience
Gareth Rushgrove
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11. Gareth RushgroveGareth Rushgrove

12. kubectl is a user interface
Gareth Rushgrove

13. YAML is a user interface
Gareth Rushgrove

14. Gareth Rushgrove
Dashboard is a user interface
Gareth Rushgrove

15. The API is a user interface
Gareth Rushgrove

16. Client libraries are a user interface
Gareth Rushgrove

17. Different interfaces are
useful in different contexts
Gareth Rushgrove

18. Different people might use
different interfaces to
achieve different tasks
Gareth Rushgrove

19. Out of the box
Just enough user interface

20. kubectl
Gareth Rushgrove

21. $ kubectl controls the Kubernetes cluster manager.
Find more information at https://github.com/kubernetes/kubernetes.
Usage:
kubectl [flags]
kubectl [command]
Available Commands:
get Display one or many resources
describe Show details of a specific resource or group of
resources
create Create a resource by filename or stdin
replace Replace a resource by filename or stdin.
patch Update field(s) of a resource by stdin.
delete Delete resources by filenames, stdin, resources and
names, or by resources and label selector.
edit Edit a resource on the server
A universal interface for actions on a Kubernetes cluster
Gareth Rushgrove

22. Gareth Rushgrove

23. YAML
Gareth Rushgrove

24. template:
metadata:
labels:
app: guestbook
tier: frontend
spec:
containers:
- name: php-redis
image: gcr.io/google_samples/gb-frontend:v4
resources:
requests:
cpu: 100m
memory: 100Mi
env:
- name: GET_HOSTS_FROM
value: dns
# If your cluster config does not include a dns service,
then to
A data format describing desired state
Gareth Rushgrove

25. API wire format as
user interface
Gareth Rushgrove

26. But isn’t YAML
declarative?
And other user interface tales

27. Yes
Gareth Rushgrove

28. Code plus data has
advantages over data alone
Gareth Rushgrove

29. The language to represent the data should
be a simple, data-only format such as JSON
or YAML, and programmatic modification of
this data should be done in a real
programming language
Gareth Rushgrove
Borg, Omega, and Kubernetes, ACM Queue,Volume 14, issue 1 http://queue.acm.org/detail.cfm?id=2898444
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30. Avoid repetition
Combine external inputs
Correctness
Abstractions
Gareth Rushgrove
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31. So why are so many people
hand writing YAML?
Gareth Rushgrove

32. Changes with kubectle patch diverge from the model
$ kubectl patch --help
Update field(s) of a resource using strategic merge patch
JSON and YAML formats are accepted.
Usage:
kubectl patch (-f FILENAME | TYPE NAME) -p PATCH [flags]
Examples:
# Partially update a node using strategic merge patch
kubectl patch node k8s-node-1 -p '{"spec":{"unschedulable":true}}'
Gareth Rushgrove

33. $ kubectl apply --help
Apply a configuration to a resource by filename or stdin.
JSON and YAML formats are accepted.
Usage:
kubectl apply -f FILENAME [flags]
Examples:
# Apply the configuration in pod.json to a pod.
$ kubectl apply -f ./pod.json
And kubectl apply requires the full object serialisation
Gareth Rushgrove

34. A familiar Kubernetes Pod definition in YAML
Gareth Rushgrove

35. What happens if you run
the same YAML file twice?
Gareth Rushgrove

36. How many times do
you have to repeat the
same label?
Gareth Rushgrove

37. kubectl is actually
pretty low-level
Gareth Rushgrove

38. kubectl get pod mypod -o yaml
| sed 's/(image: myimage):.*$/1:v4/'
| kubectl replace -f -
This is from the official kubectl help. It pipes to sed.
Gareth Rushgrove

39. Declarative code with an
idempotent runtime model
Gareth Rushgrove

40. Describe what you want
Gareth Rushgrove

41. Converge from any state
Gareth Rushgrove

42. The same Kubernetes Pod described in Puppet
Gareth Rushgrove

43. $ puppet apply examples/init.pp --test
Info: Loading facts
Notice: Compiled catalog for gareths in environment production in
1.24 seconds
Info: Applying configuration version '1453298602'
Info: Checking if sample-pod exists
Info: Creating kubernetes_pod sample-pod
Notice: /Stage[main]/Main/Kubernetes_pod[sample-pod]/ensure:
created
Notice: Applied catalog in 0.23 seconds
Running without that Pod already existing will create it
Gareth Rushgrove

44. Running a second time, nothing changes because
the Pod already existsGareth Rushgrove
$ puppet apply examples/init.pp --test
Info: Loading facts
Notice: Compiled catalog for garethr in environment production in
1.33 seconds
Info: Applying configuration version '1453298688'
Info: Checking if sample-pod exists
Notice: Applied catalog in 0.15 seconds

45. $ puppet resource kubernetes_pod sample-pod
kubernetes_pod { 'sample-pod':
ensure => 'present',
metadata => {
'creationTimestamp' => '2016-01-20T14:03:23Z',
'name' => 'sample-pod',
'namespace' => 'default',
'resourceVersion' => '4579',
'selfLink' => '/api/v1/namespaces/default/pods/sample-pod’,
'uid' => '91c8a550-bf7e-11e5-816e-42010af001b1'
},
spec => {
'containers' => [{
‘image' => 'nginx',
'imagePullPolicy' => 'IfNotPresent',
'name' => ‘container-name',
'resources' => {'requests' => {'cpu' => '100m'}}, 'terminationMessagePat
[{'mountPath' => '/var/run/secrets/kubernetes.io/serviceaccount', 'name'
'dnsPolicy' => 'ClusterFirst', 'nodeName' => 'gke-guestbook-dc15a31a-nod
puppet resource allows for interrogating an existing
Kubernetes installationGareth Rushgrove

46. $ kubectl describe pod sample-pod
Name: sample-pod
Namespace: default
Image(s): nginx
Node: gke-guestbook-dc15a31a-node-fyb6/10.240.
Start Time: Wed, 20 Jan 2016 14:03:23 +0000
Labels: <none>
Status: Running
Reason:
Message:
IP: 10.24.1.7
Replication Controllers: <none>
Containers:
container-name:
Container ID: docker://542389c5b2a98616ba3a8001029bc4a3f00d7c0
Image: nginx
Image ID: docker://407195ab8b07
The same information is still accessible via other tooling
Gareth Rushgrove

47. Other programming
languages exist
Gareth Rushgrove

48. DEMO

49. Gareth Rushgrove
More details on the official Kubernetes blog
Gareth Rushgrove

50. Imperative
Interfaces
Pragmatism and familiarity

51. Gareth Rushgrove

52. Gareth Rushgrove
Deis is an open source PaaS that provides a Heroku-
inspired workflow, using Kubernetes under the hoodGareth Rushgrove

53. Interactive CLI to login
Gareth Rushgrove
$ deis login http://deis.example.com
username: deis
password:
Logged in as deis

54. Create configs locally with the CLI
Gareth Rushgrove
$ deis create
Creating application... done, created boring-huntress
Git remote deis added

55. $ git push deis master
Counting objects: 95, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (52/52), done.
Writing objects: 100% (95/95), 20.24 KiB | 0 bytes/s, done.
Total 95 (delta 41), reused 85 (delta 37)
-----> Ruby app detected
-----> Compiling Ruby/Rack
-----> Using Ruby version: ruby-1.9.3
-----> Installing dependencies using 1.5.2
Running: bundle install --without development:test --path
vendor/bundle --binstubs vendor/bundle/bin -j4 --deployment
Fetching gem metadata from http://rubygems.org/..........
Fetching additional metadata from http://rubygems.org/..
Using bundler (1.5.2)
Installing tilt (1.3.6)
Installing rack (1.5.2)
The switch to Git for deployment
Gareth Rushgrove

56. Set config using CLI
Gareth Rushgrove
$ deis config:set FOO=1 BAR=baz && deis config:pull
$ cat .env
FOO=1
BAR=baz
$ echo "TIDE=high" >> .env
$ deis config:push
Creating config... done, v4
=== yuppie-earthman
DEIS_APP: yuppie-earthman
FOO: 1
BAR: baz
TIDE: high

57. $ deis scale web=8
Scaling processes... but first, coffee!
done in 20s
=== boring-huntress Processes
--- web:
web.1 up (v2)
web.2 up (v2)
web.3 up (v2)
web.4 up (v2)
web.5 up (v2)
web.6 up (v2)
web.7 up (v2)
web.8 up (v2)
Scale using the CLI
Gareth Rushgrove

58. Replication Controllers,
Services and Pods are
implementation details
Gareth Rushgrove

59. Kubernetes is an
implementation details from
the point of view of the user
Gareth Rushgrove

60. Kubernetes is NOT an
implementation details from
the point of view of the
administrator
Gareth Rushgrove

61. The advantages of
familiarity
Gareth Rushgrove

62. The challenges of git as
a user interface
Gareth Rushgrove

63. Ecosystems and
Interoperability
Everyone can play together

64. Gareth Rushgrove

65. Package management
Gareth Rushgrove

66. Gareth Rushgrove
Helm, a package manager for Kubernetes
Gareth Rushgrove

67. $ helm install redis-cluster
---> Running `kubectl create -f` ...
services/redis-sentinel
pods/redis-master
replicationcontrollers/redis
replicationcontrollers/redis-sentinel
---> Done
Help provides distribution tools, plus wraps kubectl
Gareth Rushgrove

68. Helm as a user interface
Gareth Rushgrove

69. Gareth Rushgrove
Charts as a place to share low level descriptions
Gareth Rushgrove

70. name: jenkins
home: https://jenkins-ci.org/
version: 0.2.0
description: The leading open-source continuous integration
server.
maintainers:
- Matt Fisher <mfisher@deis.com>
details:
Jenkins is the leading open-source continuous integration
server.
Chart.yaml metadata format
Gareth Rushgrove

71. Gareth Rushgrove
Or, what is the Kubernetes equivalent to MPM metadata?
Gareth Rushgrove

72. The importance of
sharing metadata
Gareth Rushgrove

73. Metadata as a first class
user interface
Gareth Rushgrove

74. If the API is the point of
interoperability, how can it
evolve safely?
Gareth Rushgrove

75. Gareth Rushgrove
Swagger is a specification for describing APIs
Gareth Rushgrove

76. Gareth Rushgrove
Now being developed by the Open API Initiative
Gareth Rushgrove

77. "type": "integer",
"format": "int32",
"description": "The port on each node on which this service
is exposed when type=NodePort or LoadBalancer. Usually assigned
by the system. If specified, it will be allocated to the service
if unused or else creation of the service will fail. Default is
to auto-allocate a port if the ServiceType of this Service
requires one. More info: http://releases.k8s.io/HEAD/docs/user-
guide/services.md#type--nodeport"
}
}
},
"v1.ServiceStatus": {
"id": "v1.ServiceStatus",
"description": "ServiceStatus represents the current status
of a service.",
"properties": {
"loadBalancer": {
"$ref": "v1.LoadBalancerStatus",
"description": "LoadBalancer contains the current status of
the load-balancer, if one is present."
The Kubernetes API spec is ~14,000 lines of JSON
Gareth Rushgrove

78. Some client libraries,
including the Puppet
module, are generated
from the Swagger spec
Gareth Rushgrove

79. Gareth Rushgrove

80. Standards mean going
slow in the right places
Gareth Rushgrove

81. So we can go fast
everywhere else
Gareth Rushgrove

82. Conclusions
Why Kubernetes as a platform

83. Interoperable because of a
stable set of APIs
Gareth Rushgrove

84. Platforms exposing high
level interfaces, without
limiting access to lower
level ones
Gareth Rushgrove

85. Allow for different
use-cases and different
life-cycles on the same
infrastructure
Gareth Rushgrove

86. Questions?
And thanks for listening