The document provides an overview of the key building blocks that make up Kubernetes, including: - Deployments to manage replicated applications and roll out updates. - Services for load balancing and exposing applications using labels. - Jobs and CronJobs for running periodic or one-time tasks. - Volumes for persistent storage and sharing data between containers. - StatefulSets for managing stateful applications. - Ingresses for external access to applications via an load balancer. The document outlines the purpose and usage of each building block at a high level through diagrams and YAML examples. It aims to explain the fundamental components that can be composed to build and run applications on Kubernetes.

1. Kubernetes
From sketch to production
Sergiy Shevchenko
Software Engineer
eTuitus an Infocert Company

2. Architecture
master
node 1
Docker
kubelet
kube-proxy
node 2
Docker
kubelet
kube-proxy
etcd
API
server
Controller
manager
Scheduler
kubectl
YAML declarative

3. Architecture
master
node 2
Docker
kubelet
kube-proxy
etcd
API
server
Controller
manager
Scheduler
kubectl
YAML declarative

4. Kubernetes
Building
Bricks

5. Container
Image CMD

6. Pod
Container 1 Container 2
...
localhost eth0
volume2volume1
tier: backend version: 0.1

7. Labels and selectors
tier: backend
version: 0.1
app: foo
partition: customer_1
app in (foo, bar)
partition !=
customer_1
tier == backend

8. Architecture
master
node 2
Docker
kubelet
kube-proxy
etcd
API
server
Controller
manager
Scheduler
kubectl
YAML declarative

9. Pod object (manual-bash.yaml)
apiVersion: v1
kind: Pod
metadata:
name: manual-bash
spec:
containers:
- name: bash
image: ubuntu:18.04
command: bash
args: [-c, "while true; do sleep 1; date; done"]

10. Pod object (manual-bash.yaml)
apiVersion: v1
kind: Pod
metadata:
name: manual-bash
spec:
containers:
- name: bash
image: ubuntu:18.04
command: bash
args: [-c, "while true; do sleep 1; date; done"]

11. Pod object (manual-bash.yaml)
apiVersion: v1
kind: Pod
metadata:
name: manual-bash
spec:
containers:
- name: bash
image: ubuntu:18.04
command: bash
args: [-c, "while true; do sleep 1; date; done"]

12. Pod object (manual-bash.yaml)
apiVersion: v1
kind: Pod
metadata:
name: manual-bash
spec:
containers:
- name: bash
image: ubuntu:18.04
command: bash
args: [-c, "while true; do sleep 1; date; done"]

13. Pod object (manual-bash.yaml)
apiVersion: v1
kind: Pod
metadata:
name: manual-bash
labels:
tier: backend
spec:
containers:
- name: bash
image: ubuntu:18.04
command: bash
args: [-c, "while true; do sleep 1; date; done"]

14. Replica set
N

15. Replica set
apiVersion: extensions/v1beta1
kind: ReplicaSet
metadata:
name: backend
spec:
replicas: 3
selector:
matchLabels:
tier: backend
template:
metadata:
labels:
tier: backend
spec:
containers:
- name: go-back
image: myregistry.local/backend:0.15.7

16. Deployment
N
History
Deploy
Pod
N

17. Deployment
3
0.15.1
1
0.15.2

18. Deployment
3
0.15.1
1
0.15.2

19. Deployment
2
0.15.1
1
0.15.2

20. Deployment
2
0.15.1
1
0.15.2

21. Deployment
1
0.15.1
2
0.15.2

22. Deployment
0
0.15.1
2
0.15.2

23. Deployment
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: backend
spec:
replicas: 3
selector:
matchLabels:
tier: backend
template:
metadata:
labels:
tier: backend
spec:
containers:
- name: go-back
image: myregistry.local/backend:0.15.7

24. Kubernetes building bricks
N
Deployment

25. Service
DNS
Virtual IP
LoadBalancer
Selector
Service

26. tier:db
tier:backend ver:0.15.9
tier:db
tier:backend ver:0.15.10
tier:backend ver:0.15.9
tier:backend ver:0.15.10
Backend
tier:backend

27. tier:db
tier:backend ver:0.15.9
tier:db
tier:backend ver:0.15.10
tier:backend ver:0.15.9
tier:backend ver:0.15.10
Backend
tier:backend
ver:0.15.10

28. Service
kind: Service
apiVersion: v1
metadata:
name: backend
spec:
selector:
tier: backend
ports:
- protocol: TCP
port: 80
targetPort: 8080
http://backend.svc.cluster.local

29. Service
kind: Service
apiVersion: v1
metadata:
name: backend
spec:
type: LoadBalancer
selector:
tier: backend
ports:
- protocol: TCP
port: 80
targetPort: 8080
http://backend.svc.cluster.local
AWS, DigitalOcean, ecc

30. Kubernetes building bricks
N
Deployment
Service

31. Job
Pod
Successful
completion
Job

32. Job
apiVersion: batch/v1
kind: Job
metadata:
name: migrate
spec:
template:
metadata:
name: migrate
spec:
containers:
- name: migrate
image: myregistry.local/backend:0.15.9
command: [python3, migrate]
restartPolicy: Never

33. Kubernetes building bricks
N
Deployment
Service
Job

34. Cron Job
ScheduleJob
Cron Job

35. Cron Job
apiVersion: batch/v2alpha1
kind: CronJob
metadata:
name: cron-foo
spec:
schedule: "*/1 * * * *"
jobTemplate:
spec:
template:
spec:
containers:
- name: main
image: myregistry.local/backend:0.15.9
args: [python3, cron-foo]
restartPolicy: OnFailure

36. Kubernetes building bricks
N
Deployment
Service
Job Cron Job

37. Volume
Size
Access
Storage Class
Volume
Read Write ONCE
Read Only MANY
Read Write MANY
Slow
Fast Admin defined
● awsElasticBlockStore
● azureDisk
● azureFile
● cephfs
● cinder
● configMap
● csi
● downwardAPI
● emptyDir
● fc (fibre channel)
● flexVolume
● flocker
● gcePersistentDisk
● gitRepo (deprecated)
● glusterfs
● hostPath
● iscsi
● local
● nfs
● persistentVolumeClaim
● projected
● portworxVolume
● quobyte
● rbd
● scaleIO
● secret
● storageos
● vsphereVolume

38. Kubernetes building bricks
N
Deployment
N
Replica Set
Volume Volume

39. Kubernetes building bricks
N
Deployment
N
Replica Set
Volume Volume
ReadWrite ONCE
ReadWrite ONCE

40. StatefulSet
0 1 N...
N0

41. Deployment vs StatefulSet
foo
3
Deployment
foo-asq7
foo-toxr
foo-if7n
bar
30
StatefulSet
bar-0
bar-1
bar-2

42. Deployment vs StatefulSet
N
Deployment Stateful Set
Volume
N
0

43. Kubernetes building bricks
N
Deployment
Service
Job Cron Job
Stateful Set
N
0

44. Ingress
foo bar
foo
N
bar
N
Internet
foo bar
foo
N
bar
N
Ingress
Internet

45. Ingress
Hostname
Path
TLS
Service
Ingress

46. Ingress
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: main
spec:
rules:
- host: foo.bar.com
http:
paths:
- path: /assets
backend:
serviceName: frontend
servicePort: 80
- path: /
backend:
serviceName: backend
servicePort: 80

47. Kubernetes building bricks
N
Deployment
Service
Job Cron Job
Stateful Set
N
0
Ingress

48. Thank you!
Any questions?