010.Kubernetes二進制部署kube-controller-manager

一 部署高可用kube-controller-manager

1.1 高可用kube-controller-manager介紹

本實驗部署一個三實例 kube-controller-manager 的集群，啟動后將通過競爭選舉機制產生一個 leader 節點，其它節點為阻塞狀態。當 leader 節點不可用時，阻塞的節點將再次進行選舉產生新的 leader 節點，從而保證服務的可用性。

為保證通信安全，本文檔先生成 x509 證書和私鑰，kube-controller-manager 在如下兩種情況下使用該證書：

• 與 kube-apiserver 的安全端口通信;



• 在安全端口(https，10252) 輸出 prometheus 格式的 metrics。

1.2 創建kube-controller-manager證書和私鑰

  1 [root@k8smaster01 ~]# cd /opt/k8s/work
   2 [root@k8smaster01 work]# cat > kube-controller-manager-csr.json <<EOF
   3 {
   4   "CN": "system:kube-controller-manager",
   5   "hosts": [
   6     "127.0.0.1",
   7     "172.24.8.71",
   8     "172.24.8.72",
   9     "172.24.8.73"
  10   ],
  11   "key": {
  12     "algo": "rsa",
  13     "size": 2048
  14   },
  15   "names": [
  16     {
  17       "C": "CN",
  18       "ST": "Shanghai",
  19       "L": "Shanghai",
  20       "O": "system:kube-controller-manager",
  21       "OU": "System"
  22     }
  23   ]
  24 }
  25 EOF
  26 #創建kube-controller-manager的CA證書請求文件

解釋：

hosts 列表包含所有 kube-controller-manager 節點 IP；

CN 和 O 均為 system:kube-controller-manager，kubernetes 內置的 ClusterRoleBindings system:kube-controller-manager 賦予 kube-controller-manager 工作所需的權限。

  1 [root@k8smaster01 ~]# cd /opt/k8s/work
   2 [root@k8smaster01 work]# cfssl gencert -ca=/opt/k8s/work/ca.pem \
   3 -ca-key=/opt/k8s/work/ca-key.pem -config=/opt/k8s/work/ca-config.json \
   4 -profile=kubernetes kube-controller-manager-csr.json | cfssljson -bare kube-controller-manager	#生成CA密鑰（ca-key.pem）和證書（ca.pem）

1.3 分發證書和私鑰

  1 [root@k8smaster01 ~]# cd /opt/k8s/work
   2 [root@k8smaster01 work]# source /opt/k8s/bin/environment.sh
   3 [root@k8smaster01 work]# for master_ip in ${MASTER_IPS[@]}
   4   do
   5     echo ">>> ${master_ip}"
   6     scp kube-controller-manager*.pem root@${master_ip}:/etc/kubernetes/cert/
   7   done

1.4 創建和分發kubeconfig

kube-controller-manager 使用 kubeconfig 文件訪問 apiserver，該文件提供了 apiserver 地址、嵌入的 CA 證書和 kube-controller-manager 證書：

  1 [root@k8smaster01 ~]# cd /opt/k8s/work
   2 [root@k8smaster01 work]# source /opt/k8s/bin/environment.sh
   3 [root@k8smaster01 work]# kubectl config set-cluster kubernetes \
   4   --certificate-authority=/opt/k8s/work/ca.pem \
   5   --embed-certs=true \
   6   --server=${KUBE_APISERVER} \
   7   --kubeconfig=kube-controller-manager.kubeconfig
   8 
   9 [root@k8smaster01 work]# kubectl config set-credentials system:kube-controller-manager \
  10   --client-certificate=kube-controller-manager.pem \
  11   --client-key=kube-controller-manager-key.pem \
  12   --embed-certs=true \
  13   --kubeconfig=kube-controller-manager.kubeconfig
  14 
  15 [root@k8smaster01 work]# kubectl config set-context system:kube-controller-manager \
  16   --cluster=kubernetes \
  17   --user=system:kube-controller-manager \
  18   --kubeconfig=kube-controller-manager.kubeconfig
  19 
  20 [root@k8smaster01 work]# kubectl config use-context system:kube-controller-manager --kubeconfig=kube-controller-manager.kubeconfig
  21 
  22 [root@k8smaster01 ~]# cd /opt/k8s/work
  23 [root@k8smaster01 work]# source /opt/k8s/bin/environment.sh
  24 [root@k8smaster01 work]# for master_ip in ${MASTER_IPS[@]}
  25   do
  26     echo ">>> ${master_ip}"
  27     scp kube-controller-manager.kubeconfig root@${master_ip}:/etc/kubernetes/
  28   done

1.5 創建kube-controller-manager的systemd

  1 [root@k8smaster01 ~]# cd /opt/k8s/work
   2 [root@k8smaster01 work]# source /opt/k8s/bin/environment.sh
   3 [root@k8smaster01 work]# cat > kube-controller-manager.service.template <<EOF
   4 [Unit]
   5 Description=Kubernetes Controller Manager
   6 Documentation=https://github.com/GoogleCloudPlatform/kubernetes
   7 
   8 [Service]
   9 WorkingDirectory=${K8S_DIR}/kube-controller-manager
  10 ExecStart=/opt/k8s/bin/kube-controller-manager \\
  11   --profiling \\
  12   --cluster-name=kubernetes \\
  13   --controllers=*,bootstrapsigner,tokencleaner \\
  14   --kube-api-qps=1000 \\
  15   --kube-api-burst=2000 \\
  16   --leader-elect \\
  17   --use-service-account-credentials\\
  18   --concurrent-service-syncs=2 \\
  19   --bind-address=##MASTER_IP## \\
  20   --secure-port=10252 \\
  21   --tls-cert-file=/etc/kubernetes/cert/kube-controller-manager.pem \\
  22   --tls-private-key-file=/etc/kubernetes/cert/kube-controller-manager-key.pem \\
  23   --port=0 \\
  24   --authentication-kubeconfig=/etc/kubernetes/kube-controller-manager.kubeconfig \\
  25   --client-ca-file=/etc/kubernetes/cert/ca.pem \\
  26   --requestheader-allowed-names="" \\
  27   --requestheader-client-ca-file=/etc/kubernetes/cert/ca.pem \\
  28   --requestheader-extra-headers-prefix="X-Remote-Extra-" \\
  29   --requestheader-group-headers=X-Remote-Group \\
  30   --requestheader-username-headers=X-Remote-User \\
  31   --authorization-kubeconfig=/etc/kubernetes/kube-controller-manager.kubeconfig \\
  32   --cluster-signing-cert-file=/etc/kubernetes/cert/ca.pem \\
  33   --cluster-signing-key-file=/etc/kubernetes/cert/ca-key.pem \\
  34   --experimental-cluster-signing-duration=8760h \\
  35   --horizontal-pod-autoscaler-sync-period=10s \\
  36   --concurrent-deployment-syncs=10 \\
  37   --concurrent-gc-syncs=30 \\
  38   --node-cidr-mask-size=24 \\
  39   --service-cluster-ip-range=${SERVICE_CIDR} \\
  40   --pod-eviction-timeout=6m \\
  41   --terminated-pod-gc-threshold=10000 \\
  42   --root-ca-file=/etc/kubernetes/cert/ca.pem \\
  43   --service-account-private-key-file=/etc/kubernetes/cert/ca-key.pem \\
  44   --kubeconfig=/etc/kubernetes/kube-controller-manager.kubeconfig \\
  45   --logtostderr=true \\
  46   --v=2
  47 Restart=on-failure
  48 RestartSec=5
  49 
  50 [Install]
  51 WantedBy=multi-user.target
  52 EOF

1.6 分發systemd

  1 [root@k8smaster01 ~]# cd /opt/k8s/work
   2 [root@k8smaster01 work]# source /opt/k8s/bin/environment.sh
   3 [root@k8smaster01 work]# for (( i=0; i < 3; i++ ))
   4   do
   5     sed -e "s/##MASTER_NAME##/${MASTER_NAMES[i]}/" -e "s/##MASTER_IP##/${MASTER_IPS[i]}/" kube-controller-manager.service.template > kube-controller-manager-${MASTER_IPS[i]}.service
   6   done						#修正相應IP
   7 [root@k8smaster01 work]# ls kube-controller-manager*.service
   8 [root@k8smaster01 ~]# cd /opt/k8s/work
   9 [root@k8smaster01 work]# source /opt/k8s/bin/environment.sh
  10 [root@k8smaster01 work]# for master_ip in ${MASTER_IPS[@]}
  11   do
  12     echo ">>> ${master_ip}"
  13     scp kube-controller-manager-${master_ip}.service root@${master_ip}:/etc/systemd/system/kube-controller-manager.service
  14   done						#分發system

二 啟動並驗證

2.1 啟動kube-controller-manager 服務

  1 [root@k8smaster01 ~]# cd /opt/k8s/work
   2 [root@k8smaster01 work]# source /opt/k8s/bin/environment.sh
   3 [root@k8smaster01 work]# for master_ip in ${MASTER_IPS[@]}
   4   do
   5     echo ">>> ${master_ip}"
   6     ssh root@${master_ip} "mkdir -p ${K8S_DIR}/kube-controller-manager"
   7     ssh root@${master_ip} "systemctl daemon-reload && systemctl enable kube-controller-manager && systemctl restart kube-controller-manager"
   8   done

2.2 檢查kube-controller-manager 服務

  1 [root@k8smaster01 ~]# source /opt/k8s/bin/environment.sh
   2 [root@k8smaster01 ~]# for master_ip in ${MASTER_IPS[@]}
   3   do
   4     echo ">>> ${master_ip}"
   5     ssh root@${master_ip} "systemctl status kube-controller-manager|grep Active"
   6   done

2.3 查看輸出的 metrics

  1 [root@k8smaster01 ~]# curl -s --cacert /opt/k8s/work/ca.pem --cert /opt/k8s/work/admin.pem --key /opt/k8s/work/admin-key.pem https://172.24.8.71:10252/metrics |head

注意：以上命令在 kube-controller-manager 節點上執行。

2.4 查看權限

  1 [root@k8smaster01 ~]# kubectl describe clusterrole system:kube-controller-manager

ClusteRole system:kube-controller-manager 的權限很小，只能創建 secret、serviceaccount 等資源對象，各 controller 的權限分散到 ClusterRole system:controller:XXX 中。

當在 kube-controller-manager 的啟動參數中添加 --use-service-account-credentials=true 參數，這樣 main controller 會為各 controller 創建對應的 ServiceAccount XXX-controller。內置的 ClusterRoleBinding system:controller:XXX 將賦予各 XXX-controller ServiceAccount 對應的 ClusterRole system:controller:XXX 權限。

  1 [root@k8smaster01 ~]# kubectl get clusterrole|grep controller

如deployment controller：

  1 [root@k8smaster01 ~]# kubectl describe clusterrole system:controller:deployment-controller

2.5 查看當前leader

  1 [root@k8smaster01 ~]# kubectl get endpoints kube-controller-manager --namespace=kube-system  -o yaml

kubelet 認證和授權：https://kubernetes.io/docs/admin/kubelet-authentication-authorization/#kubelet-authorization
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