部署 Kubernetes 控制节点
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
可以使用 tmux 同时登录到三点控制节点上，加快部署步骤。
部署 Kubernetes 控制平面
创建 Kubernetes 配置目录
sudo mkdir -p /etc/kubernetes/config
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/v1.18.6/bin/linux/amd64/kube-apiserver" \
"https://storage.googleapis.com/kubernetes-release/release/v1.18.6/bin/linux/amd64/kube-controller-manager" \
"https://storage.googleapis.com/kubernetes-release/release/v1.18.6/bin/linux/amd64/kube-scheduler" \
"https://storage.googleapis.com/kubernetes-release/release/v1.18.6/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 \
service-account-key.pem service-account.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=$(curl -s -H "Metadata-Flavor: Google" \
http://metadata.google.internal/computeMetadata/v1/instance/network-interfaces/0/ip)
生成 kube-apiserver.service systemd 配置文件：
cat <<EOF | sudo tee /etc/systemd/system/kube-apiserver.service
[Unit]
Description=Kubernetes API Server
Documentation=https://github.com/kubernetes/kubernetes
[Service]
ExecStart=/usr/local/bin/kube-apiserver \\
--advertise-address=${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-admission-plugins=NamespaceLifecycle,NodeRestriction,LimitRanger,ServiceAccount,DefaultStorageClass,ResourceQuota \\
--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 \\
--encryption-provider-config=/var/lib/kubernetes/encryption-config.yaml \\
--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=true' \\
--service-account-key-file=/var/lib/kubernetes/service-account.pem \\
--service-cluster-ip-range=10.32.0.0/24 \\
--service-node-port-range=30000-32767 \\
--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：
sudo mv kube-controller-manager.kubeconfig /var/lib/kubernetes/
cat <<EOF | sudo tee /etc/systemd/system/kube-controller-manager.service
[Unit]
Description=Kubernetes Controller Manager
Documentation=https://github.com/kubernetes/kubernetes
[Service]
ExecStart=/usr/local/bin/kube-controller-manager \\
--bind-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 \\
--kubeconfig=/var/lib/kubernetes/kube-controller-manager.kubeconfig \\
--leader-elect=true \\
--root-ca-file=/var/lib/kubernetes/ca.pem \\
--service-account-private-key-file=/var/lib/kubernetes/service-account-key.pem \\
--service-cluster-ip-range=10.32.0.0/24 \\
--use-service-account-credentials=true \\
--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：
sudo mv kube-scheduler.kubeconfig /var/lib/kubernetes/
cat <<EOF | sudo tee /etc/kubernetes/config/kube-scheduler.yaml
apiVersion: kubescheduler.config.k8s.io/v1alpha1
kind: KubeSchedulerConfiguration
clientConnection:
kubeconfig: "/var/lib/kubernetes/kube-scheduler.kubeconfig"
leaderElection:
leaderElect: true
EOF
cat <<EOF | sudo tee /etc/systemd/system/kube-scheduler.service
[Unit]
Description=Kubernetes Scheduler
Documentation=https://github.com/kubernetes/kubernetes
[Service]
ExecStart=/usr/local/bin/kube-scheduler \\
--config=/etc/kubernetes/config/kube-scheduler.yaml \\
--v=2
Restart=on-failure
RestartSec=5
[Install]
WantedBy=multi-user.target
EOF
启动控制器服务
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。
开启 HTTP 健康检查
Google Network Load Balancer 将用在在三个 API Server 之前作负载均衡，并可以终止 TLS 并验证客户端证书。但是该负载均衡仅支持 HTTP 健康检查，因而这里部署 nginx 来代理 API Server 的 /healthz 连接。
/healthzAPI 默认不需要认证。
sudo apt-get update
sudo apt-get install -y nginx
cat > kubernetes.default.svc.cluster.local <<EOF
server {
listen 80;
server_name kubernetes.default.svc.cluster.local;
location /healthz {
proxy_pass https://127.0.0.1:6443/healthz;
proxy_ssl_trusted_certificate /var/lib/kubernetes/ca.pem;
}
}
EOF
{
sudo mv kubernetes.default.svc.cluster.local \
/etc/nginx/sites-available/kubernetes.default.svc.cluster.local
sudo ln -s /etc/nginx/sites-available/kubernetes.default.svc.cluster.local /etc/nginx/sites-enabled/
}
sudo systemctl restart nginx
sudo systemctl enable nginx
验证
kubectl get componentstatuses --kubeconfig admin.kubeconfig
将输出结果
NAME STATUS MESSAGE ERROR
scheduler Healthy ok
controller-manager Healthy ok
etcd-0 Healthy {"health":"true"}
etcd-1 Healthy {"health":"true"}
etcd-2 Healthy {"health":"true"}
验证 Nginx HTTP 健康检查
curl -H "Host: kubernetes.default.svc.cluster.local" -i http://127.0.0.1/healthz
将输出
HTTP/1.1 200 OK
Server: nginx/1.18.0 (Ubuntu)
Date: Sat, 18 Jul 2020 06:20:48 GMT
Content-Type: text/plain; charset=utf-8
Content-Length: 2
Connection: keep-alive
Cache-Control: no-cache, private
X-Content-Type-Options: nosniff
ok
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 --kubeconfig admin.kubeconfig -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 --kubeconfig admin.kubeconfig -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：
{
KUBERNETES_PUBLIC_ADDRESS=$(gcloud compute addresses describe kubernetes-the-hard-way \
--region $(gcloud config get-value compute/region) \
--format 'value(address)')
gcloud compute http-health-checks create kubernetes \
--description "Kubernetes Health Check" \
--host "kubernetes.default.svc.cluster.local" \
--request-path "/healthz"
gcloud compute firewall-rules create kubernetes-the-hard-way-allow-health-check \
--network kubernetes-the-hard-way \
--source-ranges 209.85.152.0/22,209.85.204.0/22,35.191.0.0/16 \
--allow tcp
gcloud compute target-pools create kubernetes-target-pool \
--http-health-check kubernetes
gcloud compute target-pools add-instances kubernetes-target-pool \
--instances controller-0,controller-1,controller-2
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": "18",
"gitVersion": "v1.18.6",
"gitCommit": "dff82dc0de47299ab66c83c626e08b245ab19037",
"gitTreeState": "clean",
"buildDate": "2020-07-15T16:51:04Z",
"goVersion": "go1.13.9",
"compiler": "gc",
"platform": "linux/amd64"
}