二進制安裝kubernetes v1.11.2 （第九章 controller-manager部署）

繼續上一章部署。

9、controller-manager部署

9.1 下載二進制文件，參考 第三章

9.2  建立 kube-controller-manager 證書和私鑰

cat > kube-controller-manager-csr.json <<EOF
{
    "CN": "system:kube-controller-manager",
    "key": {
        "algo": "rsa",
        "size": 2048
    },
    "hosts": [
      "127.0.0.1",
      "192.168.56.20",
      "192.168.56.21"
    ],
    "names": [
      {
        "C": "CN",
        "ST": "BeiJing",
        "L": "BeiJing",
        "O": "system:kube-controller-manager",
        "OU": "4Paradigm"
      }
    ]
}
EOF

• hosts 列表包含全部 kube-controller-manager 節點 IP
• CN 爲 system:kube-controller-manager、O 爲 system:kube-controller-manager，kubernetes 內置的 ClusterRoleBindings system:kube-controller-manager 賦予 kube-controller-manager 工做所需的權限

生成證書和私鑰：

cfssl gencert -ca=/etc/kubernetes/cert/ca.pem \
  -ca-key=/etc/kubernetes/cert/ca-key.pem \
  -config=/etc/kubernetes/cert/ca-config.json \
  -profile=kubernetes kube-controller-manager-csr.json | cfssljson -bare kube-controller-manager
ls kube-controller-manager*.pem

分發證書到其餘master節點：

source /opt/k8s/bin/environment.sh
for master_ip in ${MASTER_IPS[@]}
  do
    echo ">>> ${master_ip}"
    scp kube-controller-manager*.pem k8s@${master_ip}:/etc/kubernetes/cert/
done

9.3 建立和分發 kubeconfig 文件

source /opt/k8s/bin/environment.sh
kubectl config set-cluster kubernetes \
  --certificate-authority=/etc/kubernetes/cert/ca.pem \
  --embed-certs=true \
  --server=${KUBE_APISERVER} \
  --kubeconfig=kube-controller-manager.kubeconfig

kubectl config set-credentials system:kube-controller-manager \
  --client-certificate=kube-controller-manager.pem \
  --client-key=kube-controller-manager-key.pem \
  --embed-certs=true \
  --kubeconfig=kube-controller-manager.kubeconfig

kubectl config set-context system:kube-controller-manager \
  --cluster=kubernetes \
  --user=system:kube-controller-manager \
  --kubeconfig=kube-controller-manager.kubeconfig

kubectl config use-context system:kube-controller-manager --kubeconfig=kube-controller-manager.kubeconfig

分發 kubeconfig 文件到全部 master 節點：

source /opt/k8s/bin/environment.sh
for master_ip in ${MASTER_IPS[@]}
  do
    echo ">>> ${master_ip}"
    scp kube-controller-manager.kubeconfig k8s@${master_ip}:/etc/kubernetes/
done

9.4 建立和分發 kube-controller-manager systemd unit 文件

source /opt/k8s/bin/environment.sh
cat > kube-controller-manager.service <<EOF
[Unit]
Description=Kubernetes Controller Manager
Documentation=https://github.com/GoogleCloudPlatform/kubernetes

[Service]
ExecStart=/opt/k8s/bin/kube-controller-manager \\
  --port=0 \\
  --secure-port=10252 \\
  --bind-address=127.0.0.1 \\
  --kubeconfig=/etc/kubernetes/kube-controller-manager.kubeconfig \\
  --service-cluster-ip-range=${SERVICE_CIDR} \\
  --cluster-name=kubernetes \\
  --cluster-signing-cert-file=/etc/kubernetes/cert/ca.pem \\
  --cluster-signing-key-file=/etc/kubernetes/cert/ca-key.pem \\
  --experimental-cluster-signing-duration=8760h \\
  --root-ca-file=/etc/kubernetes/cert/ca.pem \\
  --service-account-private-key-file=/etc/kubernetes/cert/ca-key.pem \\
  --leader-elect=true \\
  --feature-gates=RotateKubeletServerCertificate=true \\
  --controllers=*,bootstrapsigner,tokencleaner \\
  --horizontal-pod-autoscaler-use-rest-clients=true \\
  --horizontal-pod-autoscaler-sync-period=10s \\
  --tls-cert-file=/etc/kubernetes/cert/kube-controller-manager.pem \\
  --tls-private-key-file=/etc/kubernetes/cert/kube-controller-manager-key.pem \\
  --use-service-account-credentials=true \\
  --alsologtostderr=true \\
  --logtostderr=false \\
  --log-dir=/var/log/kubernetes \\
  --v=2
Restart=on
Restart=on-failure
RestartSec=5
User=k8s

[Install]
WantedBy=multi-user.target
EOF

• --port=0：關閉監聽 http /metrics 的請求，同時 --address 參數無效，--bind-address 參數有效
• --secure-port=1025二、--bind-address=0.0.0.0: 在全部網絡接口監聽 10252 端口的 https /metrics 請求
• --kubeconfig：指定 kubeconfig 文件路徑，kube-controller-manager 使用它鏈接和驗證 kube-apiserver
• --cluster-signing-*-file：簽名 TLS Bootstrap 建立的證書
• --experimental-cluster-signing-duration：指定 TLS Bootstrap 證書的有效期
• --root-ca-file：放置到容器 ServiceAccount 中的 CA 證書，用來對 kube-apiserver 的證書進行校驗
• --service-account-private-key-file：簽名 ServiceAccount 中 Token 的私鑰文件，必須和 kube-apiserver 的 --service-account-key-file 指定的公鑰文件配對使用
• --service-cluster-ip-range ：指定 Service Cluster IP 網段，必須和 kube-apiserver 中的同名參數一致
• --leader-elect=true：集羣運行模式，啓用選舉功能被選爲 leader 的節點負責處理工做，其它節點爲阻塞狀態
• --feature-gates=RotateKubeletServerCertificate=true：開啓 kublet server 證書的自動更新特性
• --controllers=*,bootstrapsigner,tokencleaner：啓用的控制器列表，tokencleaner 用於自動清理過時的 Bootstrap token
• --horizontal-pod-autoscaler-*：custom metrics 相關參數，支持 autoscaling/v2alpha1
• --tls-cert-file、--tls-private-key-file：使用 https 輸出 metrics 時使用的 Server 證書和祕鑰
• --use-service-account-credentials=true:
• User=k8s：使用 k8s 帳戶運行

kube-controller-manager 不對請求 https metrics 的 Client 證書進行校驗，故不須要指定 --tls-ca-file 參數，並且該參數已被淘汰

分發 systemd unit 文件到全部master節點：

source /opt/k8s/bin/environment.sh
for master_ip in ${MASTER_IPS[@]}
  do
    echo ">>> ${master_ip}"
    scp kube-controller-manager.service root@${master_ip}:/etc/systemd/system/
done

kube-controller-manager 的權限

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

須要在 kube-controller-manager 的啓動參數中添加 --use-service-account-credentials=true 參數，這樣 main controller 會爲各 controller 建立對應的 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。

9.5 啓動 kube-controller-manager 服務

source /opt/k8s/bin/environment.sh
for master_ip in ${MASTER_IPS[@]}
  do
    echo ">>> ${master_ip}"
    ssh root@${master_ip} "mkdir -p /var/log/kubernetes && chown -R k8s /var/log/kubernetes"
    ssh root@${master_ip} "systemctl daemon-reload && systemctl enable kube-controller-manager && systemctl restart kube-controller-manager"
done

檢查 kube-controller-manager 服務狀態

source /opt/k8s/bin/environment.sh
for master_ip in ${MASTER_IPS[@]}
  do
    echo ">>> ${master_ip}"
    ssh k8s@${master_ip} "systemctl status kube-controller-manager|grep Active"
done

確保都是  Active: active (running) 狀態

查看日誌：journalctl -u kube-controller-manager

9.6 查看輸出的 Metric

注：下面的命令在 kube-controller-manager 上執行

kube-controller-manager 監聽10252端口，接收 https 請求

[root@k8s-m1 template]# sudo netstat -lnpt|grep kube-controll
tcp        0      0 127.0.0.1:10252         0.0.0.0:*               LISTEN      23543/kube-controll 
[root@k8s-m1 template]# curl -s --cacert /etc/kubernetes/cert/ca.pem https://127.0.0.1:10252/metrics |head
# HELP ClusterRoleAggregator_adds Total number of adds handled by workqueue: ClusterRoleAggregator
# TYPE ClusterRoleAggregator_adds counter
ClusterRoleAggregator_adds 7
# HELP ClusterRoleAggregator_depth Current depth of workqueue: ClusterRoleAggregator
# TYPE ClusterRoleAggregator_depth gauge
ClusterRoleAggregator_depth 0
# HELP ClusterRoleAggregator_queue_latency How long an item stays in workqueueClusterRoleAggregator before being requested.
# TYPE ClusterRoleAggregator_queue_latency summary
ClusterRoleAggregator_queue_latency{quantile="0.5"} NaN
ClusterRoleAggregator_queue_latency{quantile="0.9"} NaN

• curl --cacert CA 證書用來驗證 kube-controller-manager https server 證書

9.7 測試 kube-controller-manager 高可用

停掉一個節點的 kube-controller-manager 服務，觀察其餘節點的日誌，看是否獲取了 leader 權限

查看當前的 leader：

[root@k8s-m1 template]# kubectl get endpoints kube-controller-manager --namespace=kube-system  -o yaml
apiVersion: v1
kind: Endpoints
metadata:
  annotations:
    control-plane.alpha.kubernetes.io/leader: '{"holderIdentity":"k8s-m1_1a33e4f7-d83a-11e8-92ec-080027675bc1","leaseDurationSeconds":15,"acquireTime":"2018-10-25T09:41:09Z","renewTime":"2018-10-25T10:09:32Z","leaderTransitions":0}'
  creationTimestamp: 2018-10-25T09:41:09Z
  name: kube-controller-manager
  namespace: kube-system
  resourceVersion: "4022"
  selfLink: /api/v1/namespaces/kube-system/endpoints/kube-controller-manager
  uid: 1a397e61-d83a-11e8-a1d2-080027675bc1

當前 leader 是 k8s-m1 

 

參考：

• 關於 controller 權限和 use-service-account-credentials 參數：https://github.com/kubernetes/kubernetes/issues/48208
• kublet 認證和受權：https://kubernetes.io/docs/admin/kubelet-authentication-authorization/#kubelet-authorization