Kubernetes is an open source system for managing containerized applications across multiple hosts that provides mechanisms for deploying, maintaining, and scaling applications. It uses concepts like pods, deployments, services, configmaps and secrets to deploy and manage applications. Key features include portability across infrastructure providers, self-healing capabilities, and enabling developers to focus on building applications without worrying about operations.

1. Kubernetes Overview
Deploy your app with confidence
Omer Barel
DevOps Engineer
omerb@codevalue.net
@omerbarel

2. Omer Barel
DevOps Engineer @ CodeValue
Husband to Naama
Father to Leo & Theo
Love Whiskey & Travelling (preferably together! )
@omerbarel
http://about.me/omerbarel

3. Agenda
Kubernetes, Simplified
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4. Greek for helmsman
Based on Borg, Google internal container
management system
First announced by Google in mid-2014
v1.0 released in July 21st, 2015 and donated to
the development community (CNCF)
A trip down memory lane
@omerbarel

5. 8: The numbers of characters between the “K”
and the “S” in Kubernetes, thus K8s
388,100: The number of comments on the
Kubernetes repository on GitHub during 2017
(making it the most-discussed repository)
60%: The percentage of users who use
Kubernetes in production applications (The New
Stack’s 2017 Kubernetes Survey)
72%: The percentage of enterprises who use
Kubernetes in production (The New Stack’s 2017
Kubernetes Survey)
Kubernetes by the numbers

6. Kubernetes in the industry
Review & improve the code
Get the community’s help
KubeCon 2017
Cloud Native
Have it your way
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7. Kubernetes is an open source system for managing
containerized applications across multiple hosts,
providing basic mechanisms for deployment,
maintenance, and scaling of applications.
What’s Kubernetes
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8. Enables you to focus on building awesome
applications while alleviating the ops stress
What’s in it for you
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9. Key Concepts
Container Orchestration
The simplicity of PaaS with the flexibility of IaaS
Enables portability across infrastructure providers
Reconciliation Loops
Drive current state → desired state
Self-healing, automagically observe
diff
act
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10. Architecture
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11. Core primitives
Pod
Container
Small group containing 1 or more tightly-
coupled containers, using shared storage
and network
Use cases:
Master & Worker (Dependency)
Data producer and provider (Shared Storage)
Close proximity for low-latency
Pod
@omerbarel

12. Core primitives
Small group containing 1 or more tightly-
coupled containers, using shared storage
and network
Use cases:
Master & Worker (Dependency)
Data producer and provider (Shared Storage)
Close proximity for low-latency
Pod
@omerbarel
apiVersion: v1
kind: Pod
metadata:
name: nginx-pod
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:latest
ports:
- containerPort: 80
env:
- name: NGINX_HOST
value: foobar.com
nginx-pod.yaml

13. Core primitives
Declaratively manage the lifecycle of
the micro service:
Creation
Scaling
Upgrade
Rollback
Termination
Contains Pods and ReplicaSets
Deployment
Deployment
ReplicaSet
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Pod
Container

14. Core primitives
Declaratively manage the lifecycle of
the micro service:
Creation
Scaling
Upgrade
Rollback
Termination
Contains Pods and ReplicaSets
Deployment
@omerbarel
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-deployment
labels:
app: nginx
spec:
selector:
matchLabels:
app: nginx
replicas: 2
template:
{pod definition}
nginx-deployment.yaml

15. Core primitives
Pods are ephemeral. wait, wait. WHAT???
They’re created and terminated
automagically, based on state changes
Their IP and name changes
Service establishes a persistent endpoint
for Pods
Allows internal and external access to
Pods (NodePort, ClusetrIP, LoadBalancer)
Labels and Selectors connects between
Service and Pods
Service
Service
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Pod
Container
Pod
Container
Pod
Container

16. Core primitives
Pods are ephemeral. wait, wait. WHAT???
They’re created and terminated
automagically, based on state changes
Their IP and name changes
Service establishes a persistent endpoint
for Pods
Allows internal and external access to
Pods (NodePort, ClusetrIP, LoadBalancer)
Labels and Selectors connects between
Service and Pods
Service
@omerbarel
apiVersion: v1
kind: Service
metadata:
name: nginx-service
labels:
app: nginx
spec:
selector:
app: nginx
ports:
- protocol: TCP
port: 8080
targetPort: 80
nginx-service.yaml

17. Core primitives
Ensures that some or all Nodes run a
copy of a Pod
Labels and Selectors determines
which nodes get a copy of the pod
Use cases:
Monitor Node resources (cpu, ram, etc.)
Collect logs
DaemonSet
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DaemonSet
Pod
Container

18. Core primitives
Ensures that some or all Nodes run a
copy of a Pod
Labels and Selectors determines
which nodes get a copy of the pod
Use cases:
Monitor Node resources (cpu, ram, etc.)
Collect logs
DaemonSet
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apiVersion: extensions/v1beta1
kind: DaemonSet
metadata:
name: fluentd-daemonset
labels:
app: fluentd
spec:
template:
metadata:
labels:
app: fluentd
spec:
tolerations:
- key: node-role.kubernetes.io/master
effect: NoSchedule
containers:
- name: fluentd
image: fluentd
fluentd-daemonset.yaml

19. Core primitives
Create a pod (or pods) that executes a
specific task and terminates it upon
successful completion
Use cases:
Task scheduling
Batch processing
CronJob
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CronJob
Pod
Container

20. Core primitives
Create a pod (or pods) that executes a
specific task and terminates it upon
successful completion
Use cases:
Task scheduling
Batch processing
CronJob
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HelloWorld-CronJob.yaml
apiVersion: batch/v1beta1
kind: CronJob
metadata:
name: hello
spec:
schedule: "*/1 * * * *"
jobTemplate:
spec:
template:
spec:
containers:
- name: hello
image: busybox
args:
- /bin/sh
- -c
- date; echo Hello World
restartPolicy: OnFailure

21. Core primitives
Keep your application portable
Decouple configuration from Pod contents
Use Cases:
Attached to container at runtime:
as file
as Environment Variables
Same Pod with different configuration per
environment – dev, stage, production
ConfigMap
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Pod
Container

22. ConfigMap - Example
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nginx-configMap.yamlnginx-pod-env.yaml
apiVersion: v1
kind: ConfigMap
metadata:
name: nginx-configMap
labels:
app: nginx
data:
hostname: foobar.com
apiVersion: v1
kind: Pod
metadata:
name: nginx-pod
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:latest
ports:
- containerPort: 80
env:
- name: NGINX_HOST
valueFrom:
configMapKeyRef:
name: nginx-configMap
key: hostname

23. Core primitives
Object that contains sensitive data
Greater access control on information such
as passwords, keys and tokens
Encoded (base64), not encrypted *
Use Cases:
Attached to container at runtime:
as file
as Environment Variables
Secret
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Pod
Container
 Encryption of data at rest is available in version 1.7 and above

24. Secret - Example
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nginx-secret.yamlnginx-pod-secret.yaml
apiVersion: v1
kind: Secret
metadata:
name: nginx-secret
labels:
app: nginx
type: Opaque
data:
password: MWYyZDFlMmU2N2R
apiVersion: v1
kind: Pod
metadata:
name: nginx-pod
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:latest
ports:
- containerPort: 80
env:
- name: NGINX_ADMIN_PASS
valueFrom:
secretKeyRef:
name: nginx-secret
key: password

25. Core primitives
Data Persistency
Toolset to provision and consume storage
Decouple storage provisioning from consumption
Decouple compute (pod) from storage
pv = PersistentVolume = storage provisioning
pvc = PersistentVolumeClaim = storage consumption
Size
Access mode
Labels & selectors
Storage class
PersistentVolumes and Claims
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Pod
Container
pv
pvc

26. Core primitives
StatefulSet
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When state matters
Manage set of pods
Maintains pod identity
Use case:
Ordered pod management
Stateful applications (Databases, Zookeeper)
StatefulSet
ReplicaSet
Pod-01
Container
Pod-02
Container
Pod-03
Container

27. StatefulSet - Example
@omerbarel
apiVersion: apps/v1
kind: StatefulSet
metadata:
name: nginx-statefulSet
labels:
app: nginx
spec:
selector:
matchLabels:
app: nginx
serviceName: “nginx”
replicas: 3
volumeClaimTemplates:
- metadata:
name: www
spec:
accessModes: [ "ReadWriteOnce" ]
storageClassName: "my-storage-class"
resources:
requests:
storage: 1Gi
template:
terminationGracePeriodSeconds: 10
{pod definition}
serviceName provides network persistency
replicas provides Pod uniqueness (unique, persistent name)
volumeClaimeTemplates provides storage persistency
terminationGracePeriodSeconds provides Pod termination control and order
nginx-StatefulSet.yaml

28. Summary
Containers Pods
Deployment
DaemonSet
CronJob
StatefulSet
Service
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app: my-app
track: stable
tier: FE
app: my-app
track: stable
tier: FE
env: devenv: dev
env: dev
app: my-app
tier: FE
track: stable
pv, pvcsecertconfigMap

29. @omerbarel

30. @omerbarel