k8s vs cfThrough the eyes of the user

HELLO!Ivan BorshukovChaosGroup@botu6aa

What is it?

k8sopen-source system for automating deployment, scaling, and management of containerized applications

What is it?

cfcode-centric platform thatruns code in any language or framework in the cloud and manages its lifecycle

k8s● Open-source● Lifecycle● Containers

What is it?

cf

● Open-source● Lifecycle● Applications

Abstractions

k8sContainerPodReplica SetDeploymentDaemon SetVolume

Abstractions

cfApplicationService

● Container● Pod - group of one or more containers with

shared storage/network● Replication Controller - ensures that a

specified number of pod replicas are running at any one time

● Deployment - provides declarative updates for Pods and Replica Sets.

Kubernetes Abstractions 101

● Service - defines a logical set of Pods and a policy by which to access them

● Volume● ConfigMap - configuration key/value pairs● Secret - sensitive data● Label & Label selector● And more...

Kubernetes Abstractions 101 (continued)

Kubernetes Abstractions 101

User Interaction

● CLI - both CF and k8s● Web interface (limited functionality) - k8s

User Interaction

K8s

Hello, World!

$ kubectl run hello-k8s --image=hello

# or

$ kubectl apply -f descriptor.yml

# or

$ kubectl create -f descriptor.yml

CF

Hello, World!

$ cf push

Running your application

cf● Blocks until app is

started● Gives you logs

k8s● Eventually starts your

containers● You need to take care

of what’s happening

k8s● Container image● ConfigMap● Secret● Volume

Configuring your application

cf● Env variables

k8s● Creating a Service

○ ENV variables○ DNS

● IaaS specific

Accessing your application

cf● https://myapp.cfapps.i

o

k8s● Direct● Using a Service

App to App communication

cf● https://myapp.cfapps.i

o

k8s● Volumes (IaaS-specific)● User-provided service● Self-hosted service

Storing state

cf● Marketplace● User-provided service

Storing state

k8s

Viewing logs

cf

$ kubectl logs $ cf logs

k8s

Attaching to your Application (ssh)

cf

$ kubectl exec

$ kubectl \ port-forward

$ cf ssh

k8s● Labels

○ env=test○ env=prod○ env=prod

● Namespaces

Environment isolation

cf● Organizations and

spaces

K8s Labels

k8s● Global or namespace● User-described, based

on rules

Role-based access control

cf● Global, org or space● Predefined roles

K8s roles example

rules:- apiGroups: [""] resources: ["pods"] verbs: ["get", "list", "watch"]

- apiGroups: [""] resources: ["configmaps"] resourceNames: ["my-config"] verbs: ["get"]

k8s● Memory & CPU● Request resources● Limit resources

Resource restriction

cf● Memory

K8s resource: request & limit

containers: - name: frontend image: wordpress resources: requests: memory: "64Mi" cpu: "250m" limits: memory: "128Mi" cpu: "500m"

k8s● Restart on crash with

backoff● Liveness probes - is app alive● Readiness probes - is app

ready to serve requests● Customizable - TCP, HTTP,

custom command

Health management

cf● Restart on crash● Health checks - TCP, HTTP,

PID

Readiness & Liveness

livenessProbe: exec: command: - cat - /tmp/healthy initialDelaySeconds: 5 periodSeconds: 2

Running locally

k8s

$ minikube start

$ minikube addons \ enable efk

Attaching to your Application (ssh)

cf

$ vagrant up$ bosh target$ bosh deploy

Containers

k8s● User provided● Privileged● Root● Stateless or stateful

Containers

cf

● Platform-created● Non-privileged● Rootless● Stateless

Usage Scenarios

k8s● Out of the box support● 3rd party components

integration (e.g. Prometheus)

Application Monitoring using PULL

cf

● Different URL for each app instance (hack)

Multiple processes

cf

● Multiple processes?

k8s● Pods - group of one or

more containers with shared storage & network

● Sidecar - extend and enhance the "main" container

K8s Sidecar

● Ambassador - proxy a local connection to the world

K8s Ambassador

● Adapter - standardize and normalize output

K8s Adapters

k8sStateful & Feature-rich

cfStateless & Simple

THANKS!Any questions?

Credits

Special thanks to all the people who made and released these awesome resources for free:✘ Presentation template by SlidesCarnival✘ Photographs by Unsplash