4.3 Kubernetes-The-Hard-Way - 部署控制节点

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2023-12-01

本部分将会在三台控制节点上部署 Kubernetes 控制服务，并配置高可用的集群架构。并且还会创建一个用于外部访问的负载均衡器。每个控制节点上需要部署的服务包括：Kubernetes API Server、Scheduler 以及 Controller Manager 等。

事前准备

以下命令需要在每台控制节点上面都运行一遍，包括 controller-0、controller-1 和 controller-2。可以使用 gcloud 命令登录每个控制节点。例如:

gcloud compute ssh controller-0

部署 Kubernetes 控制平面

下载并安装 Kubernetes Controller 二进制文件

wget -q --show-progress --https-only --timestamping 
  "https://storage.googleapis.com/kubernetes-release/release/v1.9.0/bin/linux/amd64/kube-apiserver" 
  "https://storage.googleapis.com/kubernetes-release/release/v1.9.0/bin/linux/amd64/kube-controller-manager" 
  "https://storage.googleapis.com/kubernetes-release/release/v1.9.0/bin/linux/amd64/kube-scheduler" 
  "https://storage.googleapis.com/kubernetes-release/release/v1.9.0/bin/linux/amd64/kubectl"
chmod +x kube-apiserver kube-controller-manager kube-scheduler kubectl
sudo mv kube-apiserver kube-controller-manager kube-scheduler kubectl /usr/local/bin/

配置 Kubernetes API Server

sudo mkdir -p /var/lib/kubernetes/
sudo mv ca.pem ca-key.pem kubernetes-key.pem kubernetes.pem encryption-config.yaml /var/lib/kubernetes/

使用节点的内网 IP 地址作为 API server 与集群内部成员的广播地址。首先查询当前节点的内网 IP 地址：

INTERNAL_IP=$(curl -s -H "Metadata-Flavor: Google" 
  http://metadata.google.internal/computeMetadata/v1/instance/network-interfaces/0/ip)

生成 kube-apiserver.service systemd 配置文件：

cat > kube-apiserver.service <<EOF
[Unit]
Description=Kubernetes API Server
Documentation=https://github.com/kubernetes/kubernetes
[Service]
ExecStart=/usr/local/bin/kube-apiserver \
  --admission-control=Initializers,NamespaceLifecycle,NodeRestriction,LimitRanger,ServiceAccount,DefaultStorageClass,ResourceQuota \
  --advertise-address=${INTERNAL_IP} \
  --allow-privileged=true \
  --apiserver-count=3 \
  --audit-log-maxage=30 \
  --audit-log-maxbackup=3 \
  --audit-log-maxsize=100 \
  --audit-log-path=/var/log/audit.log \
  --authorization-mode=Node,RBAC \
  --bind-address=0.0.0.0 \
  --client-ca-file=/var/lib/kubernetes/ca.pem \
  --enable-swagger-ui=true \
  --etcd-cafile=/var/lib/kubernetes/ca.pem \
  --etcd-certfile=/var/lib/kubernetes/kubernetes.pem \
  --etcd-keyfile=/var/lib/kubernetes/kubernetes-key.pem \
  --etcd-servers=https://10.240.0.10:2379,https://10.240.0.11:2379,https://10.240.0.12:2379 \
  --event-ttl=1h \
  --experimental-encryption-provider-config=/var/lib/kubernetes/encryption-config.yaml \
  --insecure-bind-address=127.0.0.1 \
  --kubelet-certificate-authority=/var/lib/kubernetes/ca.pem \
  --kubelet-client-certificate=/var/lib/kubernetes/kubernetes.pem \
  --kubelet-client-key=/var/lib/kubernetes/kubernetes-key.pem \
  --kubelet-https=true \
  --runtime-config=api/all \
  --service-account-key-file=/var/lib/kubernetes/ca-key.pem \
  --service-cluster-ip-range=10.32.0.0/24 \
  --service-node-port-range=30000-32767 \
  --tls-ca-file=/var/lib/kubernetes/ca.pem \
  --tls-cert-file=/var/lib/kubernetes/kubernetes.pem \
  --tls-private-key-file=/var/lib/kubernetes/kubernetes-key.pem \
  --v=2
Restart=on-failure
RestartSec=5
[Install]
WantedBy=multi-user.target
EOF

配置 Kubernetes Controller Manager

生成 kube-controller-manager.service systemd 配置文件：

cat > kube-controller-manager.service <<EOF
[Unit]
Description=Kubernetes Controller Manager
Documentation=https://github.com/kubernetes/kubernetes
[Service]
ExecStart=/usr/local/bin/kube-controller-manager \
  --address=0.0.0.0 \
  --cluster-cidr=10.200.0.0/16 \
  --cluster-name=kubernetes \
  --cluster-signing-cert-file=/var/lib/kubernetes/ca.pem \
  --cluster-signing-key-file=/var/lib/kubernetes/ca-key.pem \
  --leader-elect=true \
  --master=http://127.0.0.1:8080 \
  --root-ca-file=/var/lib/kubernetes/ca.pem \
  --service-account-private-key-file=/var/lib/kubernetes/ca-key.pem \
  --service-cluster-ip-range=10.32.0.0/24 \
  --v=2
Restart=on-failure
RestartSec=5
[Install]
WantedBy=multi-user.target
EOF

配置 Kubernetes Scheduler

生成 kube-scheduler.service systemd 配置文件：

cat > kube-scheduler.service <<EOF
[Unit]
Description=Kubernetes Scheduler
Documentation=https://github.com/kubernetes/kubernetes
[Service]
ExecStart=/usr/local/bin/kube-scheduler \
  --leader-elect=true \
  --master=http://127.0.0.1:8080 \
  --v=2
Restart=on-failure
RestartSec=5
[Install]
WantedBy=multi-user.target
EOF

启动控制器服务

sudo mv kube-apiserver.service kube-scheduler.service kube-controller-manager.service /etc/systemd/system/
sudo systemctl daemon-reload
sudo systemctl enable kube-apiserver kube-controller-manager kube-scheduler
sudo systemctl start kube-apiserver kube-controller-manager kube-scheduler

请等待 10 秒以便 Kubernetes API Server 初始化。

验证

kubectl get componentstatuses

将输出结果

NAME                 STATUS    MESSAGE              ERROR
controller-manager   Healthy   ok
scheduler            Healthy   ok
etcd-2               Healthy   {"health": "true"}
etcd-0               Healthy   {"health": "true"}
etcd-1               Healthy   {"health": "true"}

记得在每台控制节点上面都运行一遍，包括 controller-0、controller-1 和 controller-2。

Kubelet RBAC 授权

本节将会配置 API Server 访问 Kubelet API 的 RBAC 授权。访问 Kubelet API 是获取 metrics、日志以及执行容器命令所必需的。

这里设置 Kubeket --authorization-mode 为 Webhook 模式。Webhook 模式使用 SubjectAccessReview API 来决定授权。

gcloud compute ssh controller-0

创建 system:kube-apiserver-to-kubelet ClusterRole 以允许请求 Kubelet API 和执行许用来管理 Pods 的任务:

cat <<EOF | kubectl apply -f -
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRole
metadata:
  annotations:
    rbac.authorization.kubernetes.io/autoupdate: "true"
  labels:
    kubernetes.io/bootstrapping: rbac-defaults
  name: system:kube-apiserver-to-kubelet
rules:
  - apiGroups:
      - ""
    resources:
      - nodes/proxy
      - nodes/stats
      - nodes/log
      - nodes/spec
      - nodes/metrics
    verbs:
      - "*"
EOF

Kubernetes API Server 使用客户端凭证授权 Kubelet 为 kubernetes 用户，此凭证用 --kubelet-client-certificate flag 来定义。

绑定 system:kube-apiserver-to-kubelet ClusterRole 到 kubernetes 用户:

cat <<EOF | kubectl apply -f -
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
  name: system:kube-apiserver
  namespace: ""
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: system:kube-apiserver-to-kubelet
subjects:
  - apiGroup: rbac.authorization.k8s.io
    kind: User
    name: kubernetes
EOF

Kubernetes 前端负载均衡器

本节将会建立一个位于 Kubernetes API Servers 前端的外部负载均衡器。 kubernetes-the-hard-way 静态 IP 地址将会配置在这个负载均衡器上。

本指南创建的虚拟机内部并没有操作负载均衡器的权限，需要到创建这些虚拟机的那台机器上去做下面的操作。

创建外部负载均衡器网络资源：

gcloud compute target-pools create kubernetes-target-pool
gcloud compute target-pools add-instances kubernetes-target-pool 
  --instances controller-0,controller-1,controller-2
KUBERNETES_PUBLIC_ADDRESS=$(gcloud compute addresses describe kubernetes-the-hard-way 
  --region $(gcloud config get-value compute/region) 
  --format 'value(name)')
gcloud compute forwarding-rules create kubernetes-forwarding-rule 
  --address ${KUBERNETES_PUBLIC_ADDRESS} 
  --ports 6443 
  --region $(gcloud config get-value compute/region) 
  --target-pool kubernetes-target-pool

验证

查询 kubernetes-the-hard-way 静态 IP 地址:

KUBERNETES_PUBLIC_ADDRESS=$(gcloud compute addresses describe kubernetes-the-hard-way 
  --region $(gcloud config get-value compute/region) 
  --format 'value(address)')

发送一个查询 Kubernetes 版本信息的 HTTP 请求

curl --cacert ca.pem https://${KUBERNETES_PUBLIC_ADDRESS}:6443/version

结果为

{
  "major": "1",
  "minor": "9",
  "gitVersion": "v1.9.0",
  "gitCommit": "925c127ec6b946659ad0fd596fa959be43f0cc05",
  "gitTreeState": "clean",
  "buildDate": "2017-12-15T20:55:30Z",
  "goVersion": "go1.9.2",
  "compiler": "gc",
  "platform": "linux/amd64"
}