k8s大集群仿真

背景

当k8s集群规模大时候会有很多问题,比如调度问题

安装kwok

brew install kwok
KWOK_REPO=kubernetes-sigs/kwok
KWOK_LATEST_RELEASE=$(curl "https://api.github.com/repos/${KWOK_REPO}/releases/latest" | jq -r '.tag_name')
kubectl apply -f "https://github.com/${KWOK_REPO}/releases/download/${KWOK_LATEST_RELEASE}/kwok.yaml"
kubectl apply -f "https://github.com/${KWOK_REPO}/releases/download/${KWOK_LATEST_RELEASE}/stage-fast.yaml"

创建集群

kwokctl create cluster --name=demo
kubectl config use-context kwok-demo

创建node

kubectl apply -f - <<EOF
apiVersion: v1
kind: Node
metadata:
  annotations:
    node.alpha.kubernetes.io/ttl: "0"
    kwok.x-k8s.io/node: fake
  labels:
    beta.kubernetes.io/arch: amd64
    beta.kubernetes.io/os: linux
    kubernetes.io/arch: amd64
    kubernetes.io/hostname: kwok-node-0
    kubernetes.io/os: linux
    kubernetes.io/role: agent
    node-role.kubernetes.io/agent: ""
    type: kwok
  name: kwok-node-0
spec:
  taints: # Avoid scheduling actual running pods to fake Node
  - effect: NoSchedule
    key: kwok.x-k8s.io/node
    value: fake
status:
  allocatable:
    cpu: 32
    memory: 256Gi
    pods: 110
  capacity:
    cpu: 32
    memory: 256Gi
    pods: 110
  nodeInfo:
    architecture: amd64
    bootID: ""
    containerRuntimeVersion: ""
    kernelVersion: ""
    kubeProxyVersion: fake
    kubeletVersion: fake
    machineID: ""
    operatingSystem: linux
    osImage: ""
    systemUUID: ""
  phase: Running
EOF

创建pod

kubectl apply -f - <<EOF
apiVersion: apps/v1
kind: Deployment
metadata:
  name: fake-pod
  namespace: default
spec:
  replicas: 10
  selector:
    matchLabels:
      app: fake-pod
  template:
    metadata:
      labels:
        app: fake-pod
    spec:
      affinity:
        nodeAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            nodeSelectorTerms:
            - matchExpressions:
              - key: type
                operator: In
                values:
                - kwok
      # A taints was added to an automatically created Node.
      # You can remove taints of Node or add this tolerations.
      tolerations:
      - key: "kwok.x-k8s.io/node"
        operator: "Exists"
        effect: "NoSchedule"
      containers:
      - name: fake-container
        image: fake-image
EOF

补充

获取集群
kwokctl get clusters
删除集群
kwokctl delete cluster --name=demo