shadracnicholas / cka

Certified Kubernates Administrator (CKA) Notes

Prerequisite

1. Docker - https://docs.docker.com/get-docker/
2. kubectl - https://kubernetes.io/docs/tasks/tools/
3. kind cluster with 3 nodes - Run make create_cluster or make delete_cluster - https://kind.sigs.k8s.io/

Architectural Overview

Control Plane

Consists of multiple components that manage the cluster itself.

Control Plane Components

kube-api-server - provides k8s API Etcd - provides backend data store kube-scheduler - handles scheduling. Process of selecting available node in cluster kube-controller manager - manages utilities cloud-controller-manager - interfaces with cloud providers

k8s Nodes

The machines where the containers managed by the clusters run.

k8s Nodes Components

kubelet - k8s agent that runs on each node. Comunicates with control plane and ensures containers run as intructed. Also handles container status. container runtime - container software used to run your container. Not included in k8s. kube-proxy - network proxy for networking between nodes

Using namespaces

Its important to note that most commands you might need to specify the namespace. If not specified, the default namespace will be used. To get all namespaces - kubectl get namespaces To create a namespace - kubectl create namespace test To delete a namespace - kubectl delete namespaces test Example - Getting pods from a specific namespace - kubectl get pods -n kube-system or for all pods kubectl get pods --all-namespaces

Examination Areas

I have arranged these in the different folders. Reccomended order is;

1. Cluster Management - high availability, management tools, draining nodes, upgrading k8s with kubeadm, backup and restore etcd