Everything you want to know about Kubernetes

(preferably before using it)

Guillaume Gelin 

ramnes.eu 🇪🇺 🇫🇷

Chapter 1

The origins

Where we are coming from

Kubernetes overview

apiVersion: apps/v1
kind: Deployment
metadata:
  name: hello
spec:
  selector:
    matchLabels:
      app: hello
  replicas: 1
  template:
    metadata:
      labels:
        app: hello
    spec:
      containers:
      - name: hello
        image: numberly/hello
deployment.yaml
$ kubectl apply -f deployment.yaml
$ kubectl scale --replicas=4 deployment hello
apiVersion: v1
kind: Service
metadata:
  name: hello
spec:
  ports:
  - protocol: TCP
    port: 80
    targetPort: 8000
  selector:
    app: hello
  type: ClusterIP

service.yaml
$ kubectl apply -f service.yaml
$ kubectl get all
NAME                         READY   STATUS    RESTARTS   AGE
pod/hello-5688899d46-9nmzb   1/1     Running   0          23s

NAME            TYPE        CLUSTER-IP    EXTERNAL-IP   PORT(S)   AGE
service/hello   ClusterIP   10.16.0.122   <none>        80/TCP    19s

NAME                    READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/hello   1/1     1            1           24s

NAME                               DESIRED   CURRENT   READY   AGE
replicaset.apps/hello-5688899d46   1         1         1       24s

Why Kubernetes?

  • Developers autonomy

  • Same tooling for everyone

  • Same vocabulary for everyone

  • Write once, apply everywhere (e.g. observability)

  • Transparent self-healing

  • Resources isolation

Software engineers

Infrastructure engineers

Chapter 2

Minimum viable cluster

Requirements we settled on

  • On-premise

  • Simple networking component

  • Highly available

Choices we made

  • On-premise

  • Simple networking component

  • Highly available

https://github.com/cloudnativelabs/kube-router​

What you get or miss
at this point

Kubernetes is a platform for building platforms. It's a better place to start; not the endgame.

Kelsey Hightower

Chapter 3

Going further

A few more choices

Security

  • Encrypted etcd

  • Google sign-in + RBAC

  • Each team in its own namespace

  • "mustRunAsNonRoot" Pod Security Policy

  • "readOnlyRootFilesystem" Pod Security Policy

  • Default Network Policy ("deny *" by default)

  • Default Limit Ranges and Quotas

Developer-first experience

  • Automating as much as possible

  • Tutorials, templates, documentation

  • Certification

Tools we decided to use

https://github.com/heptiolabs/gangway 

https://github.com/danderson/metallb

https://github.com/kubernetes/ingress-nginx

https://github.com/kubernetes-sigs/external-dns

https://github.com/jetstack/cert-manager

Tools we developed ourselves

https://github.com/numberly/gitlab2rbac

https://github.com/numberly/kubemen

👀

Chapter 4

Nowadays

Current platform status

  • 14 teams

  • 100 users

  • 400 pods

Live demo?

Next steps

  • Development workflows (Continuous Delivery?)

  • A “real” storage system

  • Vertical and horizontal auto-scaling

  • Distributed tracing (with a “service mesh”)

  • Chaos monkeys

  • More nodes

Chapter 5

Step back

Our opinion on Kubernetes

  • Becoming an industry standard

  • Really solved most of our problems

  • Operating Kubernetes is complex, using it is not

  • Still has a few missing pieces

Recommendations

  • Try the “user-side” with a free cluster (e.g. KubeSail)

  • For production, use Google Kubernetes Engine

  • Operate Kubernetes only if you can dedicate people

Thank you!

https://slides.com/ramnes/everything-kubernetes

https://github.com/numberly

Everything you want to know about Kubernetes, preferably before using it

By Guillaume Gelin

Made with Slides.com

Everything you want to know about Kubernetes, preferably before using it

There is a lot of hype about Kubernetes those days, but do you know what Kubernetes really gives you, out of the box? Not as much as you might expect. « Kubernetes is a platform for building platforms. It's a better place to start; not the endgame. » Kelsey Hightower (Developer Advocate at Google) In this talk, I will present my experience as a software engineer who started building a bare-metal Kubernetes cluster without much knowledge in networking or other low-level infrastructure concepts, but with a developer background and mindset that ended up being quite useful.

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