設定 Konnectivity 服務

Konnectivity 服務為控制平面到叢集通訊提供 TCP 層級的代理。

準備開始

您需要有一個 Kubernetes 叢集，並且必須將 kubectl 命令列工具設定為與您的叢集通訊。建議在至少有兩個節點且未充當控制平面主機的叢集上執行本教學課程。如果您還沒有叢集，可以使用 minikube 建立一個。

設定 Konnectivity 服務

以下步驟需要出口 (egress) 組態，例如

admin/konnectivity/egress-selector-configuration.yaml 
apiVersion: apiserver.k8s.io/v1beta1
kind: EgressSelectorConfiguration
egressSelections:
# Since we want to control the egress traffic to the cluster, we use the
# "cluster" as the name. Other supported values are "etcd", and "controlplane".
- name: cluster
  connection:
    # This controls the protocol between the API Server and the Konnectivity
    # server. Supported values are "GRPC" and "HTTPConnect". There is no
    # end user visible difference between the two modes. You need to set the
    # Konnectivity server to work in the same mode.
    proxyProtocol: GRPC
    transport:
      # This controls what transport the API Server uses to communicate with the
      # Konnectivity server. UDS is recommended if the Konnectivity server
      # locates on the same machine as the API Server. You need to configure the
      # Konnectivity server to listen on the same UDS socket.
      # The other supported transport is "tcp". You will need to set up TLS 
      # config to secure the TCP transport.
      uds:
        udsName: /etc/kubernetes/konnectivity-server/konnectivity-server.socket

您需要設定 API 伺服器以使用 Konnectivity 服務，並將網路流量導向叢集節點

  1. 請確認您的叢集已啟用服務帳戶權杖磁碟區投影功能。自 Kubernetes v1.20 起，預設為啟用。
  2. 建立出口組態檔，例如 admin/konnectivity/egress-selector-configuration.yaml。
  3. 將 API 伺服器的 --egress-selector-config-file 標誌設定為您的 API 伺服器出口組態檔的路徑。
  4. 如果您使用 UDS 連線，請將磁碟區組態新增至 kube-apiserver
    spec:
  containers:
    volumeMounts:
    - name: konnectivity-uds
      mountPath: /etc/kubernetes/konnectivity-server
      readOnly: false
  volumes:
  - name: konnectivity-uds
    hostPath:
      path: /etc/kubernetes/konnectivity-server
      type: DirectoryOrCreate

為 konnectivity-server 產生或取得憑證與 kubeconfig。例如，您可以使用 OpenSSL 命令列工具發行 X.509 憑證，並使用來自控制平面主機的叢集 CA 憑證 /etc/kubernetes/pki/ca.crt。

openssl req -subj "/CN=system:konnectivity-server" -new -newkey rsa:2048 -nodes -out konnectivity.csr -keyout konnectivity.key
openssl x509 -req -in konnectivity.csr -CA /etc/kubernetes/pki/ca.crt -CAkey /etc/kubernetes/pki/ca.key -CAcreateserial -out konnectivity.crt -days 375 -sha256
SERVER=$(kubectl config view -o jsonpath='{.clusters..server}')
kubectl --kubeconfig /etc/kubernetes/konnectivity-server.conf config set-credentials system:konnectivity-server --client-certificate konnectivity.crt --client-key konnectivity.key --embed-certs=true
kubectl --kubeconfig /etc/kubernetes/konnectivity-server.conf config set-cluster kubernetes --server "$SERVER" --certificate-authority /etc/kubernetes/pki/ca.crt --embed-certs=true
kubectl --kubeconfig /etc/kubernetes/konnectivity-server.conf config set-context system:konnectivity-server@kubernetes --cluster kubernetes --user system:konnectivity-server
kubectl --kubeconfig /etc/kubernetes/konnectivity-server.conf config use-context system:konnectivity-server@kubernetes
rm -f konnectivity.crt konnectivity.key konnectivity.csr

接下來，您需要部署 Konnectivity 伺服器與代理程式。kubernetes-sigs/apiserver-network-proxy 是一個參考實作。

在您的控制平面節點上部署 Konnectivity 伺服器。提供的 konnectivity-server.yaml 清單檔假設 Kubernetes 元件是以靜態 Pod部署在您的叢集中。如果不是，您可以將 Konnectivity 伺服器部署為 DaemonSet。

admin/konnectivity/konnectivity-server.yaml 
apiVersion: v1
kind: Pod
metadata:
  name: konnectivity-server
  namespace: kube-system
spec:
  priorityClassName: system-cluster-critical
  hostNetwork: true
  containers:
  - name: konnectivity-server-container
    image: registry.k8s.io/kas-network-proxy/proxy-server:v0.0.37
    command: ["/proxy-server"]
    args: [
            "--logtostderr=true",
            # This needs to be consistent with the value set in egressSelectorConfiguration.
            "--uds-name=/etc/kubernetes/konnectivity-server/konnectivity-server.socket",
            "--delete-existing-uds-file",
            # The following two lines assume the Konnectivity server is
            # deployed on the same machine as the apiserver, and the certs and
            # key of the API Server are at the specified location.
            "--cluster-cert=/etc/kubernetes/pki/apiserver.crt",
            "--cluster-key=/etc/kubernetes/pki/apiserver.key",
            # This needs to be consistent with the value set in egressSelectorConfiguration.
            "--mode=grpc",
            "--server-port=0",
            "--agent-port=8132",
            "--admin-port=8133",
            "--health-port=8134",
            "--agent-namespace=kube-system",
            "--agent-service-account=konnectivity-agent",
            "--kubeconfig=/etc/kubernetes/konnectivity-server.conf",
            "--authentication-audience=system:konnectivity-server"
            ]
    livenessProbe:
      httpGet:
        scheme: HTTP
        host: 127.0.0.1
        port: 8134
        path: /healthz
      initialDelaySeconds: 30
      timeoutSeconds: 60
    ports:
    - name: agentport
      containerPort: 8132
      hostPort: 8132
    - name: adminport
      containerPort: 8133
      hostPort: 8133
    - name: healthport
      containerPort: 8134
      hostPort: 8134
    volumeMounts:
    - name: k8s-certs
      mountPath: /etc/kubernetes/pki
      readOnly: true
    - name: kubeconfig
      mountPath: /etc/kubernetes/konnectivity-server.conf
      readOnly: true
    - name: konnectivity-uds
      mountPath: /etc/kubernetes/konnectivity-server
      readOnly: false
  volumes:
  - name: k8s-certs
    hostPath:
      path: /etc/kubernetes/pki
  - name: kubeconfig
    hostPath:
      path: /etc/kubernetes/konnectivity-server.conf
      type: FileOrCreate
  - name: konnectivity-uds
    hostPath:
      path: /etc/kubernetes/konnectivity-server
      type: DirectoryOrCreate

然後在您的叢集中部署 Konnectivity 代理程式

admin/konnectivity/konnectivity-agent.yaml 
apiVersion: apps/v1
# Alternatively, you can deploy the agents as Deployments. It is not necessary
# to have an agent on each node.
kind: DaemonSet
metadata:
  labels:
    addonmanager.kubernetes.io/mode: Reconcile
    k8s-app: konnectivity-agent
  namespace: kube-system
  name: konnectivity-agent
spec:
  selector:
    matchLabels:
      k8s-app: konnectivity-agent
  template:
    metadata:
      labels:
        k8s-app: konnectivity-agent
    spec:
      priorityClassName: system-cluster-critical
      tolerations:
        - key: "CriticalAddonsOnly"
          operator: "Exists"
      containers:
        - image: us.gcr.io/k8s-artifacts-prod/kas-network-proxy/proxy-agent:v0.0.37
          name: konnectivity-agent
          command: ["/proxy-agent"]
          args: [
                  "--logtostderr=true",
                  "--ca-cert=/var/run/secrets/kubernetes.io/serviceaccount/ca.crt",
                  # Since the konnectivity server runs with hostNetwork=true,
                  # this is the IP address of the master machine.
                  "--proxy-server-host=35.225.206.7",
                  "--proxy-server-port=8132",
                  "--admin-server-port=8133",
                  "--health-server-port=8134",
                  "--service-account-token-path=/var/run/secrets/tokens/konnectivity-agent-token"
                  ]
          volumeMounts:
            - mountPath: /var/run/secrets/tokens
              name: konnectivity-agent-token
          livenessProbe:
            httpGet:
              port: 8134
              path: /healthz
            initialDelaySeconds: 15
            timeoutSeconds: 15
      serviceAccountName: konnectivity-agent
      volumes:
        - name: konnectivity-agent-token
          projected:
            sources:
              - serviceAccountToken:
                  path: konnectivity-agent-token
                  audience: system:konnectivity-server

最後，如果您的叢集中已啟用 RBAC，請建立相關的 RBAC 規則

admin/konnectivity/konnectivity-rbac.yaml 
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: system:konnectivity-server
  labels:
    kubernetes.io/cluster-service: "true"
    addonmanager.kubernetes.io/mode: Reconcile
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: system:auth-delegator
subjects:
  - apiGroup: rbac.authorization.k8s.io
    kind: User
    name: system:konnectivity-server
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: konnectivity-agent
  namespace: kube-system
  labels:
    kubernetes.io/cluster-service: "true"
    addonmanager.kubernetes.io/mode: Reconcile
上次修改時間：2023 年 12 月 28 日下午 9:39 PST：fix serviceaccount-token-volume-projection link (6a7240f55b)