二进制安装kubernetes v1.11.2 （第九章 controller-manager部署）

继续上一章部署。

九、controller-manager部署

9.1 下载二进制文件，参考 第三章

9.2  创建 kube-controller-manager 证书和私钥

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 列表包含所有 kube-controller-manager 节点 IP
• CN 为 system:kube-controller-manager、O 为 system:kube-controller-manager，kubernetes 内置的 ClusterRoleBindings system:kube-controller-manager 赋予 kube-controller-manager 工作所需的权限

生成证书和私钥：

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

分发证书到其他master节点：

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 创建和分发 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

分发 kubeconfig 文件到所有 master 节点：

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 创建和分发 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：关闭监听 http /metrics 的请求，同时 --address 参数无效，--bind-address 参数有效
• --secure-port=10252、--bind-address=0.0.0.0: 在所有网络接口监听 10252 端口的 https /metrics 请求
• --kubeconfig：指定 kubeconfig 文件路径，kube-controller-manager 使用它连接和验证 kube-apiserver
• --cluster-signing-*-file：签名 TLS Bootstrap 创建的证书
• --experimental-cluster-signing-duration：指定 TLS Bootstrap 证书的有效期
• --root-ca-file：放置到容器 ServiceAccount 中的 CA 证书，用来对 kube-apiserver 的证书进行校验
• --service-account-private-key-file：签名 ServiceAccount 中 Token 的私钥文件，必须和 kube-apiserver 的 --service-account-key-file 指定的公钥文件配对使用
• --service-cluster-ip-range ：指定 Service Cluster IP 网段，必须和 kube-apiserver 中的同名参数一致
• --leader-elect=true：集群运行模式，启用选举功能被选为 leader 的节点负责处理工作，其它节点为阻塞状态
• --feature-gates=RotateKubeletServerCertificate=true：开启 kublet server 证书的自动更新特性
• --controllers=*,bootstrapsigner,tokencleaner：启用的控制器列表，tokencleaner 用于自动清理过期的 Bootstrap token
• --horizontal-pod-autoscaler-*：custom metrics 相关参数，支持 autoscaling/v2alpha1
• --tls-cert-file、--tls-private-key-file：使用 https 输出 metrics 时使用的 Server 证书和秘钥
• --use-service-account-credentials=true:
• User=k8s：使用 k8s 账户运行

kube-controller-manager 不对请求 https metrics 的 Client 证书进行校验，故不需要指定 --tls-ca-file 参数，而且该参数已被淘汰

分发 systemd unit 文件到所有master节点：

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 的权限

ClusteRole: system:kube-controller-manager 的权限很小，只能创建 secret、serviceaccount 等资源对象，各 controller 的权限分散到 ClusterRole system:controller:XXX 中。

需要在 kube-controller-manager 的启动参数中添加 --use-service-account-credentials=true 参数，这样 main controller 会为各 controller 创建对应的 ServiceAccount XXX-controller。

内置的 ClusterRoleBinding system:controller:XXX 将赋予各 XXX-controller ServiceAccount 对应的 ClusterRole system:controller:XXX 权限。

9.5 启动 kube-controller-manager 服务

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

检查 kube-controller-manager 服务状态

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

确保都是  Active: active (running) 状态

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

9.6 查看输出的 Metric

注：下面的命令在 kube-controller-manager 上执行

kube-controller-manager 监听10252端口，接收 https 请求

[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 证书用来验证 kube-controller-manager https server 证书

9.7 测试 kube-controller-manager 高可用

停掉一个节点的 kube-controller-manager 服务，观察其他节点的日志，看是否获取了 leader 权限

查看当前的 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

当前 leader 是 k8s-m1 

 

参考：

• 关于 controller 权限和 use-service-account-credentials 参数：https://github.com/kubernetes/kubernetes/issues/48208
• kublet 认证和授权：https://kubernetes.io/docs/admin/kubelet-authentication-authorization/#kubelet-authorization