K8s

Created by Remy Rojas

Control Mgmnt

Monitor for changes to desired state. Controllers vary by resource type:

• ReplicaSet
• Deployment
• StatefulSet
• Job
• CronJob
• DeamonSet

Though can be run outside Master Node & be bespoke

Scheduler

Puts pods into available nodes

Monitors HW resources

etcd

KV store

• # instances
• DNS
• scalability
• etc

sit behind

Articles

The main idea behind Kubernetes is declarative infrastructure management, not running containers

API Server

Handles incoming requests from eg kubectl

https://nikhiljha.com/posts/kubernetes-intro/

Control Plane (Master Node)

deploy

talks to

Docker?

K8s cluster

Applications

run

Kubelet (agent)

Worker Node

1..n

physical machine or VM

containerd?

Kube-Proxy

Container Runtime

Replica set

Capacity

Available resources

Disk, Mem, Pods

type

• ClusterIP(default) - internal IP
• NodePort - NAT on Node port -> pod
• LoadBalancer - Create LB (cloud)
• ExternalName - relies on kube-dns, creates CNAME 

Properties

service - 1..n pods

Make the pod available outside the k8s virtual network.

Gives the pod a dns resolvable name within the cluster (node?)

Conditions

Ready?

Pressures

- PID

- Disk

- Memory

- NW

Pods

Addresses

External/Internal IP

Hostname

selector

chooses which pods are pointed at by the service

Containers + shared resources

label (of a pod)