Note_Tech

All technological notes.

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Kubernetes

Back

• Kubernetes
  • Cluster
  • Node
  • Master Node / Control plane
  • Worker Node
  • Container
  • Security
  • Configuration
  • Installation
  • CKA

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Cluster

• Fundamental
  • Architecture
  • YAML & Vim
  • kubectl
    • kubectl config
    • kubectl apply
  • kubeadm & init cluster
  • crictl
• Cluster Upgrade

• etcd Backup

• api server & API Object
  • Namespace
  • Label and Selector
  • Annotation
  • Logging & Event
  • Custom Resource Definition(CRD)

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Node

• Node
• Taints and Tolerations
• Cordon & Drain

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Master Node / Control plane

• API Server
• etcd
• Controller Manager
• Scheduler
  • Manual Scheduler
• Install Master Node

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Worker Node

• kubelet
  • Static Pod
• kube-proxy

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Container

• Container
  • Image
  • Back-off Mechanism & Restart Policy
  • Liveness Probe
  • Startup Probe
  • Readiness Probes
  • Lifecycle Hook
  • Command & Arg & ENV
  • Resources Request, Limit, Quota
• Multiple Containers:
  • Co-located Containers
  • Init Containers
  • Sidecar Containers
• Storage:
  • Docker Storage
  • CSI (Container Storage Interface)
  • Pod Volume
  • Common Volume Types
    • emptyDir
    • hostPath
    • Persistent Volume & Persistent Volume Claim
    • Node Local Persistent Volume
    • Dynamic Volume Provisioning & StorageClass
• Injected Data
  • ConfigMap
    • Use ConfigMap as Environment Variable
    • Use ConfigMap as Volume
  • Secret
    • Use Secret as Environment variables
    • Use Secret as Volume
  • Downward API
    • Use Downward API as Environment Variables
    • Use Downward API as Volume
  • Projected Volumes
• Networking
  • Networking Fundamental
  • Container Network Interface (CNI)
  • Cluster DNS
  • Service
    • Endpoint & EndpointSlice
    • Topology-Aware Routing
    • Service Types:
      • ClusterIP
      • NodePort
      • LoadBalancer
      • Headless Service
    • Load Balancing:
      • MetalLB
  • Ingress & IngressClass
    • Lab: nginx server with Ingress
  • Gateway API & GatewayClass
    • Lab: Gateway Use Cases
    • Lab: nginx server with Gateway
  • Lifecycle
  • PriorityClass
  • Affinity
• ReplicaSet
• Deployment
  • Deployment Rollout & Rollback
  • Common Deployment Strategies
• StatefulSets
  • StatefulSets Rollout & Rollback
• DaemonSets
  • DaemonSets Rollout & Rollback
• Job
• CronJob
• Operator

• Troubleshooting

• Scaling
  • Scaling
  • Horizontal Pod Autoscaler (HPA)
  • Vertical Pod Autoscaling (VPA)

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Security

• Security Fundamental

• Admission Controller

• Network Policy
• User
  • ServiceAccount
• Authentication
• Authorization
  • Role-based access control (RBAC)
• Security Context
  • Docker Security
• Pod Security Standards

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Configuration

• Helm Charts
  • Lab: Hello world
• Kustomize

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Installation

• minikube
• minikube Installation: RHEL9
• minikube Installation: Ubuntu
• Windows: Docker Desktop enable Kubernetes

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todo list:

• Cluster
  • Encrypting Confidential Data at Rest
    • ref: https://kubernetes.io/docs/tasks/administer-cluster/encrypt-data/
• Rel:
  • https://kubernetes.io/docs/concepts/overview/components/
• https://scriptwang.github.io/blog/#/blog/2021-06-14_K8S%E5%8E%9F%E7%90%86%E6%9E%B6%E6%9E%84%E4%B8%8E%E5%AE%9E%E6%88%98%EF%BC%88%E5%9F%BA%E7%A1%80%E7%AF%87%EF%BC%89

https://docs.linuxfoundation.org/tc-docs/certification/tips-cka-and-ckad

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CKA

• Curriculum
  • Network
  • Storage
  • Workload
  • Security
  • Cluster
• alias

export do="--dry-run=client -o yaml"
alias k=kubectl
alias kcn="kubectl config set-context --current --namespace"

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• Vim

• until the end of the line:
  • select: v$
  • delete: d$
• from the begining of the line:
  • select: v0
  • delete: d0
• until the end of the file
  • select: vG
  • delete: dG
• :set past

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• troubleshooting: Pending pod
  • describe pod for event
  • get node for status:
    • if node status == SchedulingDisabled, k uncordon
    • if node status == NotReady, kubelet stop
  • kubectl get events -n production --field-selector involvedObject.name=web

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• common errors
  • gateway httproute
    • sectionName
  • pvc
    • storageClassName='': static pv
    • omit storageClassName = default storageClassName
    • storageClassName == PV storageClassName
  • rolebinding
    • k auth can-i get pod --as

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• Command:
  • kubectl set env deployment NAME STORAGE_DIR=/local
  • kubectl set resources deployment NAME -c=nginx --limits=cpu=200m,memory=512Mi
  • kubectl set image deployment/nginx busybox=busybox nginx=nginx:1.9.1
  • kubectl set serviceaccount deployment nginx-deployment serviceaccount1

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