introduction to kubernetes slide deck by Roach

introduction to kubernetes slide deck by Roach

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Why use an orchestrator

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Application Anatomy
Application Server
Database
Web Server
Login ServicePhoto Upload
Like ServiceComment Service
Profile ServiceLogging Service
Photo ProcessingFriend Requests

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Redesign Image Sharing App
Microservice1Microservice2 Microservice
n
Team 1Team 2Team n
…
DB1…DB2DBn
Web front EndiOS AppAndroid App
API Service

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•Autonomous
•Microservicecan be upgraded independent of other systems
•Microservicecan iterate as quickly as it needs
•Polyglot application stacks (Technology Heterogenity)
•Other microservicesare black boxes to other services
•Service can be used by other projects in the organization
Advantages of Microservices

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Using dockerCLI is all well and good as a developer..
But you’re probably not going to manage production like this…
Host / VM 2
Linux Kernel
DockerEngine
Container
$sshhost1
host1# dockerrun container
$sshhost2
host2# dockerrun container
$sshhost3
host3# dockerrun container
Host / VM 3
Linux Kernel
DockerEngine
Container
Host / VM 1
Linux Kernel
DockerEngine
Container

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ContainerContainerContainer
Kubernetes
Load Balancing
Health ChecksLog Aggregation / Access
Developer API
Container orchestration is a must.
$kubectlscale deployment <name> --replicas=3
Once you’ve built your containers and pushed them. Container Orchestrators manage running
containers across a pool of resources for you

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•Docker Swarm / EE
•Apache Marathon
•Rancher (seem to be moving towards k8s)
What are other orchestrators?

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What is kubernetes?

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•Container Orchestration
•Keeping your containers up, scaling them, routing traffic to them
•Kubernetes != Docker though K8S uses Docker (or CoreOS rkt)
What is Kubernetes?

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•MiniKube(local workstation)
•Installers (on-prem, hybrid, custom)
•Kops (part of core kubernetes.iogithub)
•Kubespray(Ansible+ Terraform)
•Etc, etc…
•Cloud
•Google Container Engine (GKE J)
•Azure Container Service
•Amazon EKS
•Etc…
Installation options

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•Step-by-step tutorial of how to assemble a kubernetescluster
•https://github.com/kelseyhightower/kubernetes-the-hard-way
Sidebar: K8S the hard way

12. Source: http://x-team.com/2016/07/introduction-kubernetes-architecture/

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Kubernetes Components

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Kubernetes main Features
PodsDeploymentsServicesIngress

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•Group of one or more containers, shared storage, and options for
how to run the containers
•Share IP address and port space
•Atomic unit of management
Pods
Source: http://kubernetes.io/docs/user-guide/pods/

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•Rolling upgrades
•Declare intent: How many replicas should be running of a given
pod?
•Namespace
•Labels
•Ports that should be exposed
Deployments

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•Abstraction for the mortality of Pods
•Provide single stable name and address for a set of pods inside the
cluster (aka service discovery).
Services
Source: http://kubernetes.io/docs/user-guide/services/

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•Abstraction for services
•An Ingressis a set of rules for directing inbound traffic to a service.
•An Ingress Controller is a service that listens for the creation of new
services and does reverse proxy (nginx, traefik, f5 loadbalancer)
Ingress
See: http://kubernetes.io/docs/user-guide/ingress/

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K8S templates: deployment
# k8s/dev/api-deployment.yaml
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: rest-api-swagger
spec:
replicas: 2
template:
metadata:
labels:
app: rest-api-swagger
spec:
containers:
-name: rest-api-swagger
image: ciscodevnet/rest-api-swagger:latest
ports:
-containerPort: 10010

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K8S templates: service
# k8s/services/api-service-lb.yaml
kind: Service
apiVersion: v1
metadata:
name: rest-api-swagger
spec:
type: LoadBalancer# or NodePort, etc.
ports:
-name: http
port: 8080
targetPort: 10010
protocol: TCP
selector:
app: rest-api-swagger

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Manual kubectldeployment
$ kubectlapply -f k8s/dev/api-deployment.yaml
$ kubectlapply -f k8s/services/api-service-lb.yaml
$ kubectldescribe deployment
$ kubectldescribe service rest-api-swagger
$ kubectldelete -f k8s/dev/api-deployment.yaml
$ kubectldelete -f k8s/services/api-service-lb.yaml