Kubernetes Architecture and Fundamentals April 21, 2014 Null Bangalore Public Puliya 

Who am I? ● DevOps Engineer at Razorpay ○ AWS VPCs ○ Self-hosted Kubernetes ○ CI ○ Datastores @hashfyre 

Objective ● Understand the problem K8S tries to solve ● Delve into K8S architecture, to decipher how does it do this. ● Dissect K8S API Server to understand it’s components ● Understand user-space interactions with K8S ● Touch upon K8S resources that builds your application stack ● Deploy a local K8S Cluster with Minikube ● Deploy basic apps on it 

Materials ● Kubernetes Learning Materials: https://goo.gl/Rywkpd 

10 mins Introduction to K8S 10 mins K8S Architecture 10 mins Control Plane components overview 20 mins Get minikube up and running on localhost 40 mins Deploying K8S manifests on minikube 

K8S: Introduction 

Orchestration Platform & Toolkit ● Abstractions on top of containers ○ Pods ● Pod Scheduling and Lifecycle ● Cluster Networking ○ Pod-to-Pod ○ Host-to-Pod ● Service Load Balancing ● Service DNS ● Storage Volume Management ○ Persistent Layer ● Microservice centric ● Organize your workload as desired ● Composable building blocks for your app ● Platform and toolkit ○ Build on top of Open APIs 

Architecture 

Source: http://k8s.info/cs.html#cs-menu Kubernetes Architecture: Physical Layout 

Source: http://k8s.info/cs.html#cs-menu Kubernetes Architecture: Abstractions Overview 

Source: http://k8s.info/cs.html#cs-menu Kubernetes Architecture: Detailed Abstractions 

How Kubelet Schedules Containers 

Source: Kubernetes - a comprehensive Overview Kubernetes Stack on Cloud Providers 

Getting Things Running... 

Minikube Setup ● macOS ○ brew cask install minikube ● Linux ○ curl -Lo minikube https://storage.googleapis.com/minikube /releases/latest/minikube-linux-amd64 && ○ chmod +x minikube && sudo mv minikube /usr/local/bin/ ● Windows ○ minikube-windows-amd64.exe 

macOS with xhyve OSX ● Download [Docker for Mac] ( https://docs.docker.com/docker-for-mac/ ) ● Install [minikube] ( https://github.com/kubernetes/minikube/releases ) ● Install xhyve driver brew install docker-machine-driver-xhyve ● docker-machine-driver-xhyve need root owner and uid ● sudo chown root:wheel $(brew --prefix)/opt/docker-machine-driver-xhyve/bin/docker-machine-driver-xhyve ● sudo chmod u+s $(brew --prefix)/opt/docker-machine-driver-xhyve/bin/docker-machine-driver-xhyve ● Set minikube to use xhyve minikube config set vm-driver xhyve ● Install kubectl - brew install kubectl ● Start minikube minikube start ● Set kubectl to use minikube kubectl config use-context minikube ● Confirm its working kubectl get services --all-namespaces ● Share Docker Daemon with minikube eval $(minikube docker-env) 

Familiarizing K8S Objects / Kinds 

Hands On: Pods, Deployments, Services Expose a Pod as a Service ● Redis-service encapsulating a redis pod ● A web-service depending on the redis-service as backend Expose a Deployment as a Service ● Redis-service encapsulating a redis pod ● A web-service depending on the redis-service as backend ○ Encapsulating multiple running replicas https://github.com/hashfyre/k8s-tutes 

Hands On: Statefulsets Web Deployment with Redis HA Statefulset ● Primary and Secondary Redis-services with Sentinel and Statefulsets ● A web-service depending on the redis-service as backend ○ Encapsulating multiple running replicas https://github.com/corybuecker/redis-stateful-set 

Hands On: Daemonset Deploy Prometheus + Grafana + nodeexporter ● Node-exporter daemonset ● Prometheus deployment + service ● Grafana deployment + service https://github.com/bakins/minikube-prometheus-demo 

Thanks. @hashfyre /Hashfyre