配置条件触发自动切流

为集群安装CPD组件识别集群

在配置自动切流前，您需要在集群中安装CPD（cluster-problem-detector）组件，以自动探测集群CoreDNS域名解析功能是否正常，并进行上报。

CPD会周期性地解析kubernetes.default域名，将解析结果更新到Node对象的conditions中。主CPD Pod会收集各个Node上的conditions，判断集群域名解析功能是否正常，并将该判断结果上报到至集群联邦控制面。

CPD以DaemonSet的形式部署，需要独立部署在每个目标集群的所有节点上。CPD的配置文件示例如下所示，请参见表1中的描述修改相关参数。

kind: DaemonSet
apiVersion: apps/v1
metadata:
  name: cluster-problem-detector
  namespace: kube-system
  labels:
    app: cluster-problem-detector
spec:
  selector:
    matchLabels:
      app: cluster-problem-detector
  template:
    metadata:
      labels:
        app: cluster-problem-detector
    spec:
      containers:
        - image: swr.cn-north-4.myhuaweicloud.com/hwofficial/cluster-problem-detector:<federation-version>
          name: cluster-problem-detector
          command:
            - /bin/sh
            - '-c'
            - /var/paas/cluster-problem-detector/cluster-problem-detector
              --karmada-kubeconfig=/tmp/config
              --karmada-context=federation
              --cluster-name=<your-cluster-name>
              --host-name=${HOST_NAME}
              --bind-address=${POD_ADDRESS}
              --healthz-port=8081
              --detectors=*
              --coredns-detect-period=5s
              --coredns-success-threshold=30s
              --coredns-failure-threshold=30s
              --coredns-stale-threshold=60s
          env:
            - name: POD_ADDRESS
              valueFrom:
                fieldRef:
                  apiVersion: v1
                  fieldPath: status.podIP
            - name: POD_NAME
              valueFrom:
                fieldRef:
                  apiVersion: v1
                  fieldPath: metadata.name
            - name: POD_NAMESPACE
              valueFrom:
                fieldRef:
                  apiVersion: v1
                  fieldPath: metadata.namespace
            - name: HOST_NAME
              valueFrom:
                fieldRef:
                  apiVersion: v1
                  fieldPath: spec.nodeName
          livenessProbe:
            httpGet:
              path: /healthz
              port: 8081
              scheme: HTTP
            initialDelaySeconds: 3
            timeoutSeconds: 3
            periodSeconds: 5
            successThreshold: 1
            failureThreshold: 3
          readinessProbe:
            httpGet:
              path: /healthz
              port: 8081
              scheme: HTTP
            initialDelaySeconds: 3
            timeoutSeconds: 3
            periodSeconds: 5
            successThreshold: 1
            failureThreshold: 3
          volumeMounts:
            - mountPath: /tmp
              name: karmada-config
      serviceAccountName: cluster-problem-detector
      volumes:
        - configMap:
            name: karmada-kubeconfig
            items:
              - key: kubeconfig
                path: config
          name: karmada-config
      securityContext:
        fsGroup: 10000
        runAsUser: 10000
        seccompProfile:
          type: RuntimeDefault
      hostAliases:
        hostnames:
          - <host name of karmada server>
        ip: <ip of host name of karmada server>
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: cluster-problem-detector
  namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: cpd-binding
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: system:cluster-problem-detector
subjects:
  - kind: ServiceAccount
    name: cluster-problem-detector
    namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: system:cluster-problem-detector
rules:
  - apiGroups:
      - ""
    resources:
      - nodes
    verbs:
      - get
      - list
      - watch
  - apiGroups:
      - ""
    resources:
      - nodes/status
    verbs:
      - patch
      - update
  - apiGroups:
      - ""
      - events.k8s.io
    resources:
      - events
    verbs:
      - create
      - patch
      - update
  - apiGroups:
      - coordination.k8s.io
    resources:
      - leases
    verbs:
      - get
      - list
      - watch
      - create
      - update
      - patch
      - delete
---
apiVersion: v1
kind: ConfigMap
metadata:
  name: karmada-kubeconfig
  namespace: kube-system
data:
  kubeconfig: |+
    <kubeconfig-of-karmada>

检查CPD组件是否正常运行

部署CPD组件后，请检查CPD组件是否正常运行。

• 执行以下命令，检查节点的conditions中是否有“ServiceDomainNameResolutionReady”类型的 condition 出现，并检查该condition的“lastHeartBeatTime”是否及时更新。

  kubectl get node <node-name> -oyaml | grep -B4 ServiceDomainNameResolutionReady

  若节点中没有上述类型的condition出现，或者该condition“lastHeartBeatTime”长时间不更新：

  1. 请检查CPD中的pod是否处于Ready状态。
  2. 请检查成员集群中是否有“LoadCorednsConditionFailed”或者“StoreCorednsConditionFailed”类型的事件。若存在，请按事件中的错误提示进行处理。
• 执行以下命令，检查集群联邦cluster对象中是否有“ServiceDomainNameResolutionReady”类型的condition出现。

  kubectl --kubeconfig <kubeconfig-of-federation> get cluster <cluster-name> -oyaml | grep ServiceDomainNameResolutionReady

  若cluster对象中没有上述类型的condition：

  1. 请检查CPD日志中是否出现“failed to sync corendns condition to control plane, requeuing”错误。
  2. 请检查kubeconfig配置是否有误。若kubeconfig有更新，请重新部署CPD。
  3. 请检查CPD所在节点的网络和下载kubeconfig文件所使用的VPC网络是否打通。

配置条件触发自动切流策略

在CPD组件部署成功并正常运行后，您需要创建Remedy对象，以在特定触发条件下执行特定动作，如在集群CoreDNS组件故障后执行MCI切流。

Remedy对象的配置文件示例如下所示。示例YAML定义了一个Remedy对象，可以通过member1或member2集群上的CPD上报CoreDNS解析功能，在功能故障时自动将该集群上的MCI进行切流。详细的Remedy对象参数说明请参见表2。

apiVersion: remedy.karmada.io/v1alpha1
kind: Remedy
metadata:
  name: foo
spec:
  clusterAffinity:
    clusterNames:
      - member1
      - member2
  decisionMatches:
  - clusterConditionMatch:
      conditionType: ServiceDomainNameResolutionReady
      operator: Equal
      conditionStatus: "False"
  actions:
  - TrafficControl