010.Kubernetes二進位部署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，啟動後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 ...

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，啟動後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 的安全埠通信;

在安全埠(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 工作所需的許可權。

  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

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

2.4 查看許可權

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

ClusteRole system:kube-controller-manager 的許可權很小，只能創建 secret、serviceaccount 等資源對象，各 controller 的許可權分散到 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 許可權。

  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