Kwok

建立抽象的 node，可以模擬 pod 部署在上面

Install

安裝 mac cli

brew install kwok

Deploy `kwok` in a Cluster

`kwok` in Cluster | KWOK (k8s.io )

# KWOK repository
KWOK_REPO=kubernetes-sigs/kwok
# Get latest
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"

不太清楚為何要有第三步

如果加入第二步

image 1.png

但還是呈現 notReady

image 2.png

就算加入第三步也不行，要一開始就先設定好

Stage

Stages | KWOK (k8s.io )

image 3.png

node, pod 都有自己的 stage，加入 stage 的 api spec，可以模擬 node/pod 的各種過程

像是符合 selector: env=prod，其中的 Finalizers 要不一樣。

Node stages
Pending: The node is being provisioned and is not yet ready for use.
Ready: The node is ready for use and can be scheduled for pods.
Not Ready: The node is not ready for use and cannot be scheduled for pods.
Terminating: The node is being terminated and will be removed from the cluster.
Unknown: The state of the node is unknown.

Pod stages
Pending: The pod is being created and is not yet running.
Running: The pod is running and ready to accept traffic.
Succeeded: The pod has completed its execution and has exited with a zero status code.
Failed: The pod has failed to execute and has exited with a non-zero status code.
Unknown: The state of the pod is unknown.

kind: Stage
apiVersion: kwok.x-k8s.io/v1alpha1
metadata:
  name: <string>
spec:
  resourceRef:
    apiGroup: <string>
    kind: <string>
  selector:
    matchLabels:
      <string>: <string>
    matchAnnotations:
      <string>: <string>
    matchExpressions:
    - key: <expressions-string>
      operator: <string>
      values:
      - <string>
  delay:
    durationMilliseconds: <int>
    durationFrom:
      expressionFrom: <expressions-string>
    jitterDurationMilliseconds: <int>
    jitterDurationFrom:
      expressionFrom: <expressions-string>
  next:
    statusTemplate: <string>
    finalizers:
      add:
      - value: <string>
      remove:
      - value: <string>
      empty: <bool>
    delete: <bool>
  immediateNextStage: <bool>

selector: 滿足的 pod, node 會執行下面的狀態
delay: 可以加入隨機的等待時間
next:
- statusTemplate: 編寫 pod 與內部 container 的狀態
- finalizers: 如何移除相關性的 (Finalizers are namespaced keys that tell Kubernetes to wait until specific conditions are met before it fully deletes resources marked for deletion.)

下面是 pod-ready 為例子

image 4.png

Use as node

# filename: node.yaml
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

kubectl apply -f node.yaml

image 5.png

image 6.png

node 有 taint

image 7.png

image 8.png

加入 pod

# pod.yaml
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

image 9.png

Kwok#

Install#

Deploy kwok in a Cluster#

Stage#

Use as node#

加入 pod#