Day 02：CKA簡介

Kubernetes 簡介

Kubernetes是現在最熱門的分散式系統架構。簡單來說，就是將各個伺服器 (Server) 當成節點 (Node) ，使用一套系統來集中管理，在各個節點上部署容器 (Container) 來執行各種任務。而這些任務可大可小，有可能是網站的後端、深度學習用來對資料進行預處理的小程式，甚至只是一個只會定期發送”Hello world!”的腳本。

而早期的版本是以Docker為基礎，使用其當作預設CRI (容器運行時街口, Container Runtime Interface) 來建立容器。 而在版本1.24以後，若是想要繼續使用Docker來建造容器，則需要安裝cri-docker。

CNCF之Kubernetes證照

1. CKA (Certified Kubernetes Admin, Kubernetes 管理員認證)
2. CKAD (Certified Kubernetes Application Developer, Kubernetes 應用程式開發者認證)
3. CKS (Certified Kubernetes Security Specialist, Kubernetes 認證安全專家，須先通過CKA認證)

CKA簡介

• 價格：395美金

  記得去年的時候還是300，到今年我報名的時候漲到375，不過每年都會有好幾次的特價。

• 報名一年內必須考完，66分通過測驗，失敗可重考一次

• 2小時考試時間

• 可以選擇英文或簡體中文

• 線上測驗

• 證照有效期限為三年

• 考試範圍：

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

這些是從CNCF找到的考試範圍，可以發現範圍非常的廣，很多東西都是在準備考試之前根本沒摸過的，像是etcd的備份與還原。

參考資料

https://www.gushiciku.cn/pl/pupM/zh-tw

https://medium.com/@Appletone/cka-考試全攻略流程-3a28d1b73eea

https://training.linuxfoundation.org/certification/certified-kubernetes-administrator-cka/