CKA vs CKAD vs CKS
======
###### tags: `k8s` `certification`
> CNCF和Linux基金會聯合推出的K8S考試認證。委託給 PSI 來進行監督考試[color=#907bf7]
> > All the exam costs $399, with one free retake.
> > 難易度：CKAD -> CKA -> CKS

## CKA
> Have the skills, knowledge, and competency to perform the responsibilities of Kubernetes administrators.
+ **Certified Kubernetes Administrator**
+ focuses on testing the **knowledge** and **skills** of a candidate in the field of `all aspects of Kubernetes cluster concepts`
+ ==managing and operating== the Kubernetes cluster
+ it involves everything from **`creating`**, **`managing`**, and **`troubleshooting`** a cluster
+ Now, after September 2020 CNCF has reduced the course curriculum and has decreased the duration to **2 hours**.
+ The exam is based on Kubernetes **v1.28**
+ Certification Valid for 3 Years

### cka curriculum
+ *==25%==* - ***Cluster Architecture, Installation & Configuration***
+ Manage role based access control (RBAC)
+ Use Kubeadm to install a basic cluster
+ Manage a highly-available Kubernetes cluster
+ Provision underlying infrastructure to deploy a Kubernetes cluster
+ Perform a version upgrade on a Kubernetes cluster using Kubeadm
+ Implement etcd backup and restore
+ *==15%==* - ***Workloads & Scheduling***
+ Understand deployments and how to perform rolling update and rollbacks
+ Use ConfigMaps and Secrets to configure applications
+ Know how to scale applications
+ Understand the primitives used to create robust, self-healing, application deployments
+ Understand how resource limits can affect Pod scheduling
+ Awareness of manifest management and common templating tools
+ *==20%==* - ***Services & Networking***
+ Understand host networking configuration on the cluster nodes
+ Understand connectivity between Pods
+ Understand ClusterIP, NodePort, LoadBalancer service types and endpoints
+ Know how to use Ingress controllers and Ingress resources
+ Know how to configure and use CoreDNS
+ Choose an appropriate container network interface plugin
+ *==10%==* - ***Storage***
+ Understand storage classes, persistent volumes
+ Understand volume mode, access modes and reclaim policies for volumes
+ Understand persistent volume claims primitive
+ Know how to configure applications with persistent storage
+ *==30%==* - ***Troubleshooting***
+ Evaluate cluster and node logging
+ Understand how to monitor applications
+ Manage container stdout & stderr logs
+ Troubleshoot application failure
+ Troubleshoot cluster component failure
+ Troubleshoot networking

## CKAD
> Can design, build and deploy cloud-native applications for Kubernetes.
+ **Certified Kubernetes Application Developer**
+ ==managing and deploying== applications to the Kubernetes cluster
+ It emphasizes only the topics required for application **`development`**, **`deployment`**, and **`management`**

### ckad curriculum
+ *==20%==* - ***Application Design and Build***
+ Define, build and modify container images
+ Choose and use the right workload resource (Deployment, DaemonSet, CronJob, etc.)
+ Understand multi-container Pod design patterns (e.g. sidecar, init and others)
+ Utilize persistent and ephemeral volumes
+ *==20%==* - ***Application Deployment***
+ Use Kubernetes primitives to implement common deployment strategies (e.g. blue/green or canary)
+ Understand Deployments and how to perform rolling updates
+ Use the Helm package manager to deploy existing packages
+ Kustomize
+ *==15%==* - ***Application Observability and Maintenance***
+ Understand API deprecations
+ Implement probes and health checks
+ Use built-in CLI tools to monitor Kubernetes applications
+ Utilize container logs
+ Debugging in Kubernetes
+ *==25%==* - ***Application Environment, Configuration and Security***
+ Discover and use resources that extend Kubernetes (CRD, Operators)
+ Understand authentication, authorization and admission control
+ Understand requests, limits, quotas
+ Understand ConfigMaps
+ Define resource requirements
+ Create & consume Secrets
+ Understand ServiceAccounts
+ Understand Application Security (SecurityContexts, Capabilities, etc.)
+ *==20%==* - ***Services and Networking***
+ Demonstrate basic understanding of NetworkPolicies
+ Provide and troubleshoot access to applications via services
+ Use Ingress rules to expose applications

## CKS
> has the skills, knowledge, and competence on a broad range of best practices for securing container-based applications and Kubernetes platforms during build, deployment and runtime
+ **Certified Kubernetes Security Specialis**
+ consist of a **`performance-based`** certification exam and
+ has the skills, knowledge, and competence on a broad range of best practices for **`securing`** container-based applications and Kubernetes platforms during **`build`**, **`deployment`**, and **`runtime`**.

### cks curriculum
+ *==10%==* - ***Cluster Setup***
+ *==15%==* - ***Cluster Hardening***
+ *==15%==* - ***System Hardening***
+ *==20%==* - ***Minimize Microservice Vulnerabilities***
+ *==20%==* - ***Supply Chain Security***
+ *==20%==* - ***Monitoring, Logging and Runtime Security***

## 考生心得
+ CKA會考etcd和k8s部署相關的內容，CKAD不會涉及
+ CKAD會有cronjob和ha的內容，CKA不會涉及
+ CKAD比CKA難度更大一些

## resource
+ [CKA vs CKAD vs CKS – What is the Difference](https://k21academy.com/docker-kubernetes/cka-v-s-ckad-v-s-cks/)
+ [cncf/curriculum](https://github.com/cncf/curriculum)