KUBERNETES 101

HANDS ON WORKSHOP

KUBERNETES MEETUP PUNE10 June 2017

HARSHAL SHAHSolutions Architect

infraCloud technologies (www.infracloud.io )

https://twitter.com/harshal2623

1st Kubernetes partner India2nd in APAC region

Rancher partner - APAC

InfraCloud has published a FREE eBook on

“Scaling and deploying Kubernetes”

http://info.rancher.com/deploying-scaling-kubernetes-ebook

TIMELINES

Time (Minutes - total 135) Agenda

00 - 15 Introduction & Setting up

15 - 45 Quick walkthrough of concepts

45 - 75 3 concepts, code & labs - 10 minute each

75 - 80 Break

80 - 110 3 concept, code & labs - 10 min each

110 - 135 Open House

Lab - Setup Kubernetes in GKE & laptop

• GKE Cluster creation

• Kubectl on Google Cloud Console

• Run command “kubectl proxy --port=8080”

• Click this button

• Append “/ui/” as shown in below highlight to

open the Kubernetes Dashboard

● git clone https://github.com/infracloudio/kubernetes-101

TABLE OF CONTAINERS.. ..

• What is Kubernetes, exactly?

• How to setup a Kubernetes Cluster?

• Various ways to get started with a Kubernetes cluster

• Kubernetes Architecture

• Kubernetes Concepts

• POD, Deployments, Services, Labels & Selectors etc.

• Kubectl Usage

• Deploying app with Helm

KUBERNETES - THE BOOKISH DEFINITION

• Kubernetes is an open-source platform for automating deployment, scaling, and operations of application containers across clusters of hosts, providing container-centric infrastructure (From

http://kubernetes.io/docs/whatisk8s/)

Open source project by Google

Primarily targeted at containerized

workloads

Platform - automates deployment, scaling etc.

Abstracts hosts and underlying

infrastructure from you

Portable - Run on public/private cloud, data

center, your laptop -doesn’t matter

Self - healing: It restarts, replaces, scales, monitors

Containers

Extensible - replace certain components if you want

to. Extend with pluggable architecture

KUBERNETES HAS COMMON PATTERNS/DESIGNS

Need to run related processes together in a

shared context

Integrating with underlying storage (Block or Bucket

based)

Check health of applications and maintain

certain number of instances.

Scale instances based on triggers.

Load balancing between multiple instances of a

container

Provide easy and scalable way to locate and reach

services (Aka service discovery and naming)

Monitoring and log management

Tagging and searching instances dynamically to

do certain operations (For example list all web servers

across all applications)

Rolling updates, Canary deployments

Everything is API based- so can be integrated with

external systems.

SETTING UP KUBERNETES

On Cloud & managed

Google Container

EngineStackpointCloud

Tectonic from CoreOS

OpenShift Online

DIY - any cloud/data center

Kubeadm(official utility)

DIY On steroids

KOPS (Targeted to

AWS)

Kismatic from Apprenda

Rancher -provides

enterprise features, multi cluster support

Redhat OpenShift -comes with complete lifecycle features

Many more: http://kubernetes.io/docs/getting-started-guides

Platform9

KUBERNETES ARCHITECTURE

Image Source: info.rancher.com/deploying-scaling-kubernetes-ebook

POD

• Related containers together

• Share same IP, port space & storage etc.

• It’s a single unit for all practical purposes

Code & Demo: Pod - create and destroy

Pod

flask

redis

NFSiSCSIGCE

10.10.1.100

POD - LAB

What just happened?

* Courtesy Julia Evans blog which

is an awesome place to learn many

things http://jvns.ca

Twitter : @b0rk

HEALTHCHECK

Hey, app v1... You ready?

KubeletPod

app v1

HEALTHCHECK - LAB

DEPLOYMENT

• Drive desired state

• Maintain desired POD instances

• Enable deployment mechanisms such as rolling deploy, Canary, pause/resume etc.

Deployment

ReplicaSet

Pod

DEPLOYMENT LAB

ROLLING UPGRADE - DEPLOYMENT LAB

SERVICES

• Provide a fixed endpoint for PODs irrespective of deletion/movement/modification of POD

• Expose services/endpoints to outside cluster or to world

• Services utilize labels to target PODs to represent

SERVICE TYPES

ExternalName (Kubernetes 1.5 onwards)

• Serves as a way to return an alias to an external service residing outside the cluster.

ClusterIP (Default)

• Exposes service only within cluster

NodePort

• Creates a ClusterIP + exposes the same port on every node/host. This is typically used if you want to use an external loadBalancer

LoadBalancer

• NodePort+Creates a LB in cloud provider (Such as ELB) and points to respective ports

SERVICES- LAB

LABELS AND SELECTORS

Labels:

“relase”:”1.4”

“environment”:”QA”

“app”:”billing”

Selectors:

env = prod

release in (1.3, 1.4)

app != payment

• Classification mechanism

• Labels

• Tag things

• Think like “roles”

• Selectors

• Filters & conditions

EXAMPLE

Pod

hello

Pod

hello

labels:version: v1track: stable

labels:version: v1track: test

selector: “version=v1” selector: “track=stable”

Pod

hello

Pod

hello

labels:version: v1track: stable

labels:version: v1track: test

SECRETS & CONFIG MAPS

• Secrets

• Deliver sensitive data to intended target

• ConfigMap

• Configuration properties

NAMESPACES & NODES

• Namespaces

• Logically separate cluster

• Nodes

• Info about nodes

MORE TYPES

Storage classes for handling persistent data. They interact with cloud

provider's storage.

StatefulSet - for managing clusters with

strong identity requirements (Kafka,

Elastic, Zookeeper etc.)

DaemonSet - things which need to run on a

set or all nodes of cluster. For example

logging agents

Job - ensures a certain number of PODs execute

the process and upon completion terminates.

(For batch jobs)

RESOURCES• The workshop material & codelabs at

https://github.com/GoogleCloudPlatform/kubernetes-workshops

• http://kubernetesbyexample.com

• http://info.rancher.com/deploying-scaling-kubernetes-ebook

• Another awesome resource for kubernetes hands on is from Kamal Marhubi at Part1, Part2, Part3

Scalable Microservices with Kubernetes

https://www.udacity.com/course/scalable-microservices-with-kubernetes--ud615

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THANK YOU!