Kubernetes CKA Prep Notes

CKA Curriculum

This page will be a living document to help me prepare for the CKA (Certified Kubernetes Administrator) exam.

The CKA curriculum can be found on github. As of 2022-02-13 it is targetting kubernetes 1.22. It looks intense.

CKA Curriculum

https://raw.githubusercontent.com/cncf/curriculum/master/CKA_Curriculum_v1.22.pdf

25% - Cluster Architecture, Installation & Configuration

Manage role based access control (RBAC)
- https://kubernetes.io/docs/reference/access-authn-authz/rbac/
Use Kubeadm to install a basic cluster
- swapoff -a
  - nano /etc/fstab and comment out the swap line
- install containerd
- apt update && apt install containerd
- https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/install-kubeadm/
- all the other stuff
- kubeadm init –pod-network-cidr=192.168.0.0/16 –config kubeadm-config.yaml
  - make sure cgroup driver is systemd

# kubeadm-config.yaml
kind: ClusterConfiguration
apiVersion: kubeadm.k8s.io/v1beta3
kubernetesVersion: v1.23.4
networking:
  podSubnet: "192.168.0.0/16" # --pod-network-cidr
---
kind: KubeletConfiguration
apiVersion: kubelet.config.k8s.io/v1beta1
cgroupDriver: systemd

* cni, install calico
    * https://projectcalico.docs.tigera.io/getting-started/kubernetes/quickstart
    * are there docs on the kubernetes site?


* older docker stuff
    * [switch docker to systemd cgroup driver](https://kubernetes.io/docs/setup/production-environment/container-runtimes/)
    * Seriously ???
    * /etc/docker/daemon.json 

{
  "exec-opts": ["native.cgroupdriver=systemd"]
}

Manage a highly-available Kubernetes cluster
- https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/high-availability/
Provision underlying infrastructure to deploy a Kubernetes cluster
- Does this mean installing docker or cri-o?
- https://kubernetes.io/docs/setup/production-environment/container-runtimes/ ??????
Perform a version upgrade on a Kubernetes cluster using Kubeadm
- https://kubernetes.io/docs/tasks/administer-cluster/kubeadm/kubeadm-upgrade/
Implement etcd backup and restore
- https://kubernetes.io/docs/tasks/administer-cluster/configure-upgrade-etcd/#backing-up-an-etcd-cluster

15% - Workloads & Scheduling

Understand deployments and how to perform rolling update and rollbacks
- https://kubernetes.io/docs/concepts/workloads/controllers/deployment/
Use ConfigMaps and Secrets to configure applications
- https://kubernetes.io/docs/concepts/configuration/configmap/
- https://kubernetes.io/docs/concepts/configuration/secret/
Know how to scale applications
- Increase the replica set? Or horizontal pod audoscaler? Something else?
- https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale-walkthrough/
- https://kubernetes.io/docs/concepts/workloads/controllers/deployment/ - set the replicas, increase for more deployments
Understand the primitives used to create robust, self-healing, application deployments
Understand how resource limits can affect Pod scheduling
- https://kubernetes.io/docs/concepts/configuration/manage-resources-containers/
Awareness of manifest management and common templating tools
- operators? helm? kustomize?

20% - Services & Networking

Understand host networking configuration on the cluster nodes
- https://kubernetes.io/docs/concepts/cluster-administration/networking/
Understand connectivity between Pods
Understand ClusterIP, NodePort, LoadBalancer service types and endpoints
Know how to use Ingress controllers and Ingress resources
- https://kubernetes.io/docs/concepts/services-networking/ingress/
- https://kubernetes.io/docs/concepts/services-networking/ingress-controllers/
Know how to configure and use CoreDNS
- https://kubernetes.io/docs/tasks/administer-cluster/dns-custom-nameservers/
Choose an appropriate container network interface plugin

10% - Storage

Understand storage classes, persistent volumes
- https://kubernetes.io/docs/concepts/storage/storage-classes/
- https://kubernetes.io/docs/concepts/storage/persistent-volumes/
Understand volume mode, access modes and reclaim policies for volumes
Understand persistent volume claims primitive
- https://kubernetes.io/docs/concepts/storage/volumes/#persistentvolumeclaim
Know how to configure applications with persistent storage
- https://kubernetes.io/docs/concepts/storage/storage-classes/#local - manual
- https://kubernetes.io/docs/concepts/storage/storage-classes/#gce-pd - google cloud

30% - Troubleshooting

Evaluate cluster and node logging
- https://kubernetes.io/docs/tasks/debug-application-cluster/debug-cluster/#looking-at-logs
Understand how to monitor applications
- https://kubernetes.io/docs/tasks/debug-application-cluster/debug-application-introspection/
Manage container stdout & stderr logs
Troubleshoot application failure
- https://kubernetes.io/docs/tasks/debug-application-cluster/debug-application/
Troubleshoot cluster component failure
- https://kubernetes.io/docs/tasks/debug-application-cluster/debug-cluster/#a-general-overview-of-cluster-failure-modes
Troubleshoot networking
- https://kubernetes.io/docs/tasks/administer-cluster/dns-debugging-resolution/