在 Kubernetes 集群中，将 Pod 调度到指定节点有多种实现方案，其中使用 Label 标签配合 NodeSelector 节点选择器是最直观且广泛应用的方法。操作前，需要先为节点添加标签，这相当于为服务器设置一个“身份标识”，调度器会根据该标识精准分配 Pod 到目标节点。

执行以下命令即可为节点添加标签：

$ kubectl label node master nodename=master

该命令为 master 节点赋予一个 nodename=master 的标签。其他节点可参照此方式，按照自定义命名规范打上类似 nodename=worker1、nodename=worker2 等标签，后续在 Pod 配置中直接引用即可实现精准调度。

YAML 配置文件示例

节点标签设置完成后，即可编写 YAML 配置文件。以下提供一套完整的资源定义，包含 RBAC 权限、通过 DaemonSet 部署 Traefik 作为 Ingress Controller、Service 端口暴露、Deployment 部署 Jenkins 并指定调度至 master 节点，以及 Ingress 路由规则。用户可直接复制使用，仅需根据实际环境调整 host 域名和访问路径即可。

---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: traefik-ingress-controller
rules:
  - apiGroups:
      - ""
    resources:
      - services
      - endpoints
      - secrets
    verbs:
      - get
      - list
      - watch
  - apiGroups:
      - extensions
    resources:
      - ingresses
    verbs:
      - get
      - list
      - watch
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: traefik-ingress-controller
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: traefik-ingress-controller
subjects:
  - kind: ServiceAccount
    name: traefik-ingress-controller
    namespace: kube-system
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: traefik-ingress-controller
  namespace: kube-system
---
kind: DaemonSet
apiVersion: extensions/v1beta1
metadata:
  name: traefik-ingress-controller
  namespace: kube-system
  labels:
    k8s-app: traefik-ingress-lb
spec:
  template:
    metadata:
      labels:
        k8s-app: traefik-ingress-lb
        name: traefik-ingress-lb
    spec:
      serviceAccountName: traefik-ingress-controller
      terminationGracePeriodSeconds: 60
      hostNetwork: true
      containers:
      - image: traefik
        name: traefik-ingress-lb
        ports:
        - name: http
          containerPort: 80
          hostPort: 80
        - name: admin
          containerPort: 8080
        securityContext:
          capabilities:
            drop:
              - ALL
            add:
              - NET_BIND_SERVICE
        args:
        - --api
        - --kubernetes
        - --logLevel=INFO
---
apiVersion: v1
kind: Service
metadata:
  name: traefik-web-ui
  namespace: kube-system
spec:
  selector:
    k8s-app: traefik-ingress-lb
  ports:
  - name: web
    port: 80
    targetPort: 8080
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: jenkins-deployment
  namespace: kube-system
  labels:
    app: jenkins
spec:
  replicas: 1
  selector:
    matchLabels:
      app: jenkins
  template:
    metadata:
      labels:
        app: jenkins
    spec:
      terminationGracePeriodSeconds: 60
      containers:
      - name: jenkins
        image: jenkins/jenkins:lts
        imagePullPolicy: IfNotPresent
        env:
        - name: JENKINS_OPTS
          value: "--prefix=/jenkins"
        ports:
        - name: web
          containerPort: 8080
          protocol: TCP
        - name: agent
          containerPort: 50000
          protocol: TCP
        volumeMounts:
        - name: jenkins-home
          mountPath: /var/jenkins_home
      volumes:
      - name: jenkins-home
        hostPath:
          path: /root/jenkins-home
      nodeSelector:
        nodename: master
---
apiVersion: v1
kind: Service
metadata:
  name: jenkins-service
  namespace: kube-system
  labels:
    app: jenkins
spec:
  ports:
  - port: 8888
    targetPort: 8080
    name: web
  - port: 50000
    targetPort: 50000
    name: agent
  selector:
    app: jenkins
---
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: traefik-web-ui
  namespace: kube-system
  annotations:
    kubernetes.io/ingress.class: traefik
    traefik.frontend.rule.type: PathPrefixStrip
spec:
  rules:
  - host: c4.k8s.com
    https:
      paths:
      - path: /
        backend:
          serviceName: traefik-web-ui
          servicePort: web
---
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: jenkins-ingress
  namespace: kube-system
  annotations:
    kubernetes.io/ingress.class: traefik
    traefik.ingress.kubernetes.io/app-root: /jenkins
    traefik.ingress.kubernetes.io/rule-type: PathPrefix
    traefik.frontend.passHostHeader: "true"
spec:
  rules:
  - host: c4.k8s.com
    https:
      paths:
      - path: /jenkins
        backend:
          serviceName: jenkins-service
          servicePort: web

该整套配置的核心逻辑为：首先利用 DaemonSet 在每个节点上运行一个 Traefik 实例（采用 hostNetwork: true 模式直接占用宿主机端口），随后通过 Deployment 部署 Jenkins 服务，并在 Pod 的 spec 中设置 nodeSelector: nodename: master，确保 Jenkins 仅被调度到含有 nodename=master 标签的节点。最后，通过两个 Ingress 资源分别暴露 Traefik 管理界面与 Jenkins 服务，统一使用域名 c4.k8s.com 进行访问。

需要注意：hostNetwork: true 表示容器将直接复用宿主机网络栈，因此需确保宿主机端口不与其它服务冲突。此外，Jenkins 的数据卷使用 hostPath 类型，在生产环境中建议替换为 PV/PVC 以保障数据持久化与可迁移性。本示例仅作演示用途，旨在帮助快速验证功能。