二进制方式部署k8s的work节点

kubernetes worker 节点运行如下组件：

+ docker
+ kubelet
+ kube-proxy
+ flanneld
+ kube-nginx

部署kube-nginx是为了访问 kube-apiserver 集群，kubelet、kube-proxy通过本地的 nginx（监听 127.0.0.1）访问 kube-apiserver，从而实现 kube-apiserver 的高可用

kube-nginx部署请参考：https://www.cnblogs.com/deny/p/12260717.html 里的安装配置nginx代理

CA证书请参考：https://www.cnblogs.com/deny/p/12259778.html

节点信息：

+ zhangjun-k8s01：192.168.1.201
+ zhangjun-k8s02：192.168.1.202
+ zhangjun-k8s03：192.168.1.203

所需的变量存放在/opt/k8s/bin/environment.sh

#!/usr/bin/bash

# 生成 EncryptionConfig 所需的加密 key
export ENCRYPTION_KEY=$(head -c 32 /dev/urandom | base64)

# 集群各机器 IP 数组
export NODE_IPS=(192.168.1.201 192.168.1.202 192.168.1.203)

# 集群各 IP 对应的主机名数组
export NODE_NAMES=(zhangjun-k8s01 zhangjun-k8s02 zhangjun-k8s03)

# etcd 集群服务地址列表
export ETCD_ENDPOINTS="https://192.168.1.201:2379,https://192.168.1.202:2379,https://192.168.1.203:2379"

# etcd 集群间通信的 IP 和端口
export ETCD_NODES="zhangjun-k8s01=https://192.168.1.201:2380,zhangjun-k8s02=https://192.168.1.202:2380,zhangjun-k8s03=https://192.168.1.203:2380"

# kube-apiserver 的反向代理(kube-nginx)地址端口
export KUBE_APISERVER="https://127.0.0.1:8443"

# 节点间互联网络接口名称
export IFACE="ens33"

# etcd 数据目录
export ETCD_DATA_DIR="/data/k8s/etcd/data"

# etcd WAL 目录，建议是 SSD 磁盘分区，或者和 ETCD_DATA_DIR 不同的磁盘分区
export ETCD_WAL_DIR="/data/k8s/etcd/wal"

# k8s 各组件数据目录
export K8S_DIR="/data/k8s/k8s"

# docker 数据目录
export DOCKER_DIR="/data/k8s/docker"

## 以下参数一般不需要修改

# TLS Bootstrapping 使用的 Token，可以使用命令 head -c 16 /dev/urandom | od -An -t x | tr -d ' ' 生成
BOOTSTRAP_TOKEN="41f7e4ba8b7be874fcff18bf5cf41a7c"

# 最好使用 当前未用的网段 来定义服务网段和 Pod 网段

# 服务网段，部署前路由不可达，部署后集群内路由可达(kube-proxy 保证)
SERVICE_CIDR="10.254.0.0/16"

# Pod 网段，建议 /16 段地址，部署前路由不可达，部署后集群内路由可达(flanneld 保证)
CLUSTER_CIDR="172.30.0.0/16"

# 服务端口范围 (NodePort Range)
export NODE_PORT_RANGE="30000-32767"

# flanneld 网络配置前缀
export FLANNEL_ETCD_PREFIX="/kubernetes/network"

# kubernetes 服务 IP (一般是 SERVICE_CIDR 中第一个IP)
export CLUSTER_KUBERNETES_SVC_IP="10.254.0.1"

# 集群 DNS 服务 IP (从 SERVICE_CIDR 中预分配)
export CLUSTER_DNS_SVC_IP="10.254.0.2"

# 集群 DNS 域名（末尾不带点号）
export CLUSTER_DNS_DOMAIN="cluster.local"

# 将二进制目录 /opt/k8s/bin 加到 PATH 中
export PATH=/opt/k8s/bin:$PATH

注意：如果没有特殊指明，本文档的所有操作**均在 zhangjun-k8s01 节点上执行**，然后远程分发文件和执行命令

安装依赖包

source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    ssh root@${node_ip} "yum install -y epel-release"
    ssh root@${node_ip} "yum install -y conntrack ipvsadm ntp ntpdate ipset jq iptables curl sysstat libseccomp && modprobe ip_vs "
  done

一、安装和配置 flanneld

flannel 集群部署请参考：https://www.cnblogs.com/deny/p/12260072.html

二、安装和配置 kube-nginx

kube-nginx部署请参考：https://www.cnblogs.com/deny/p/12260717.html 里的安装配置nginx代理

三、部署 docker 组件

docker 运行和管理容器，kubelet 通过 Container Runtime Interface (CRI) 与它进行交互。

1、安装docker

1）下载和分发 docker 二进制文件

到 [docker 下载页面](https://download.docker.com/linux/static/stable/x86_64/) 下载最新发布包

cd /opt/k8s/work
wget https://download.docker.com/linux/static/stable/x86_64/docker-19.03.5.tgz
tar -xvf docker-19.03.5.tgz

2）分发二进制文件到所有 worker 节点

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    scp docker/*  root@${node_ip}:/opt/k8s/bin/
    ssh root@${node_ip} "chmod +x /opt/k8s/bin/*"
  done

2、创建和分发 systemd unit 文件

1）创建模板文件

cd /opt/k8s/work
cat > docker.service <<"EOF"
[Unit]
Description=Docker Application Container Engine
Documentation=http://docs.docker.io

[Service]
WorkingDirectory=##DOCKER_DIR##
Environment="PATH=/opt/k8s/bin:/bin:/sbin:/usr/bin:/usr/sbin"
EnvironmentFile=-/run/flannel/docker
ExecStart=/opt/k8s/bin/dockerd $DOCKER_NETWORK_OPTIONS
ExecReload=/bin/kill -s HUP $MAINPID
Restart=on-failure
RestartSec=5
LimitNOFILE=infinity
LimitNPROC=infinity
LimitCORE=infinity
Delegate=yes
KillMode=process

[Install]
WantedBy=multi-user.target
EOF

EOF 前后有双引号，这样 bash 不会替换文档中的变量，如 `$DOCKER_NETWORK_OPTIONS` (这些环境变量是 systemd 负责替换的。)；
dockerd 运行时会调用其它 docker 命令，如 docker-proxy，所以需要将 docker 命令所在的目录加到 PATH 环境变量中；
flanneld 启动时将网络配置写入 `/run/flannel/docker` 文件中，dockerd 启动前读取该文件中的环境变量 `DOCKER_NETWORK_OPTIONS` ，然后设置 docker0 网桥网段；
如果指定了多个 `EnvironmentFile` 选项，则必须将 `/run/flannel/docker` 放在最后(确保 docker0 使用 flanneld 生成的 bip 参数)；
docker 需要以 root 用于运行；
docker 从 1.13 版本开始，可能将 **iptables FORWARD chain的默认策略设置为DROP**，从而导致 ping 其它 Node 上的 Pod IP 失败，遇到这种情况时，需要手动设置策略为 `ACCEPT`：iptables -P FORWARD ACCEPT，并且把以下命令写入 `/etc/rc.local` 文件中，防止节点重启**iptables FORWARD chain的默认策略又还原为DROP** ，/sbin/iptables -P FORWARD ACCEPT

2）分发 systemd unit 文件到所有 worker 机器

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
sed -i -e "s|##DOCKER_DIR##|${DOCKER_DIR}|" docker.service
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    scp docker.service root@${node_ip}:/etc/systemd/system/
  done

3、配置和分发 docker 配置文件

1）配置docker-daemon.json

使用国内的仓库镜像服务器以加快 pull image 的速度，同时增加下载的并发数 (需要重启 dockerd 生效)：

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
cat > docker-daemon.json <<EOF
{
    "registry-mirrors": ["https://docker.mirrors.ustc.edu.cn","https://hub-mirror.c.163.com"],
    "insecure-registries": ["docker02:35000"],
    "max-concurrent-downloads": 20,
    "live-restore": true,
    "max-concurrent-uploads": 10,
    "debug": true,
    "data-root": "${DOCKER_DIR}/data",
    "exec-root": "${DOCKER_DIR}/exec",
    "log-opts": {
      "max-size": "100m",
      "max-file": "5"
    }
}
EOF

2）分发 docker 配置文件到所有 worker 节点

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    ssh root@${node_ip} "mkdir -p  /etc/docker/ ${DOCKER_DIR}/{data,exec}"
    scp docker-daemon.json root@${node_ip}:/etc/docker/daemon.json
  done

4、启动 docker 服务

source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    ssh root@${node_ip} "systemctl daemon-reload && systemctl enable docker && systemctl restart docker"
  done

1）检查服务运行状态

source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    ssh root@${node_ip} "systemctl status docker|grep Active"
  done

确保状态为 `active (running)`，否则查看日志，确认原因：journalctl -u docker

2）检查 docker0 网桥

source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    ssh root@${node_ip} "/usr/sbin/ip addr show flannel.1 && /usr/sbin/ip addr show docker0"
  done

确认各 worker 节点的 docker0 网桥和 flannel.1 接口的 IP 处于同一个网段中(如下 172.30.128.0/32 位于 172.30.128.1/21 中)

注意: 如果您的服务安装顺序不对或者机器环境比较复杂, docker服务早于flanneld服务安装，此时 worker 节点的 docker0 网桥和 flannel.1 接口的 IP可能不会同处同一个网段下，这个时候请先停止docker服务, 手工删除docker0网卡，重新启动docker服务后即可修复:

systemctl stop docker
ip link delete docker0
systemctl start docker

3）查看 docker 的状态信息

ps -elfH|grep docker

docker info

四、部署 kubelet 组件

kubelet 运行在每个 worker 节点上，接收 kube-apiserver 发送的请求，管理 Pod 容器，执行交互式命令，如 exec、run、logs 等。

kubelet 启动时自动向 kube-apiserver 注册节点信息，内置的 cadvisor 统计和监控节点的资源使用情况。

为确保安全，部署时关闭了 kubelet 的非安全 http 端口，对请求进行认证和授权，拒绝未授权的访问(如 apiserver、heapster 的请求)。

1、下载和分发 kubelet 二进制文件

1）从 [CHANGELOG 页面](https://github.com/kubernetes/kubernetes/blob/master/CHANGELOG.md) 下载二进制 tar 文件并解压

cd /opt/k8s/work
wget https://dl.k8s.io/v1.14.2/kubernetes-server-linux-amd64.tar.gz
tar -xzvf kubernetes-server-linux-amd64.tar.gz
cd kubernetes
tar -xzvf  kubernetes-src.tar.gz

其他下载链接：

wget https://storage.googleapis.com/kubernetes-release/release/v1.14.2/kubernetes-node-linux-amd64.tar.gz
wget https://storage.googleapis.com/kubernetes-release/release/v1.14.2/kubernetes-server-linux-amd64.tar.gz
wget https://storage.googleapis.com/kubernetes-release/release/v1.14.2/kubernetes-client-linux-amd64.tar.gz
wget https://storage.googleapis.com/kubernetes-release/release/v1.14.2/kubernetes.tar.gz

2）将二进制文件 kubelet拷贝到所有 work 节点

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    scp kubernetes/server/bin/{kubelet,kubectl,kubeadm,kube-proxy} root@${node_ip}:/opt/k8s/bin/
    ssh root@${node_ip} "chmod +x /opt/k8s/bin/*"
  done

2、创建 kubelet bootstrap kubeconfig 文件

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_name in ${NODE_NAMES[@]}
  do
    echo ">>> ${node_name}"

    # 创建 token
    export BOOTSTRAP_TOKEN=$(kubeadm token create 
      --description kubelet-bootstrap-token 
      --groups system:bootstrappers:${node_name} 
      --kubeconfig ~/.kube/config)

    # 设置集群参数
    kubectl config set-cluster kubernetes 
      --certificate-authority=/etc/kubernetes/cert/ca.pem 
      --embed-certs=true 
      --server=${KUBE_APISERVER} 
      --kubeconfig=kubelet-bootstrap-${node_name}.kubeconfig

    # 设置客户端认证参数
    kubectl config set-credentials kubelet-bootstrap 
      --token=${BOOTSTRAP_TOKEN} 
      --kubeconfig=kubelet-bootstrap-${node_name}.kubeconfig

    # 设置上下文参数
    kubectl config set-context default 
      --cluster=kubernetes 
      --user=kubelet-bootstrap 
      --kubeconfig=kubelet-bootstrap-${node_name}.kubeconfig

    # 设置默认上下文
    kubectl config use-context default --kubeconfig=kubelet-bootstrap-${node_name}.kubeconfig
  done

向 kubeconfig 写入的是 token，bootstrap 结束后 kube-controller-manager 为 kubelet 创建 client 和 server 证书

1）查看 kubeadm 为各节点创建的 token

$ kubeadm token list --kubeconfig ~/.kube/config
TOKEN                     TTL       EXPIRES                     USAGES                   DESCRIPTION               EXTRA GROUPS
3gzd53.ahl5unc2d09yjid9   23h       2019-05-27T11:29:57+08:00   authentication,signing   kubelet-bootstrap-token   system:bootstrappers:zhangjun-k8s02
82jfrm.um1mkjkr7w2c7ex9   23h       2019-05-27T11:29:56+08:00   authentication,signing   kubelet-bootstrap-token   system:bootstrappers:zhangjun-k8s01
b1f7np.lwnnzur3i8ymtkur   23h       2019-05-27T11:29:57+08:00   authentication,signing   kubelet-bootstrap-token   system:bootstrappers:zhangjun-k8s03

token 有效期为 1 天，超期后将不能再被用来 boostrap kubelet，且会被 kube-controller-manager 的 token cleaner 清理；
kube-apiserver 接收 kubelet 的 bootstrap token 后，将请求的 user 设置为 `system:bootstrap:<Token ID>`，group 设置为 `system:bootstrappers`，后续将为这个 group 设置 ClusterRoleBinding；

2）查看各 token 关联的 Secret

$ kubectl get secrets  -n kube-system|grep bootstrap-token
bootstrap-token-3gzd53                           bootstrap.kubernetes.io/token         7      33s
bootstrap-token-82jfrm                           bootstrap.kubernetes.io/token         7      34s
bootstrap-token-b1f7np                           bootstrap.kubernetes.io/token         7      33s

3）分发 bootstrap kubeconfig 文件到所有 worker 节点

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_name in ${NODE_NAMES[@]}
  do
    echo ">>> ${node_name}"
    scp kubelet-bootstrap-${node_name}.kubeconfig root@${node_name}:/etc/kubernetes/kubelet-bootstrap.kubeconfig
  done

3、创建和分发 kubelet 参数配置文件

从 v1.10 开始，部分 kubelet 参数需在**配置文件**中配置，`kubelet --help` 会提示：

DEPRECATED: This parameter should be set via the config file specified by the Kubelet's --config flag

创建 kubelet 参数配置文件模板（可配置项参考[代码中注释](https://github.com/kubernetes/kubernetes/blob/master/pkg/kubelet/apis/config/types.go)

1）创建文件

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
cat > kubelet-config.yaml.template <<EOF
kind: KubeletConfiguration
apiVersion: kubelet.config.k8s.io/v1beta1
address: "##NODE_IP##"
staticPodPath: ""
syncFrequency: 1m
fileCheckFrequency: 20s
httpCheckFrequency: 20s
staticPodURL: ""
port: 10250
readOnlyPort: 0
rotateCertificates: true
serverTLSBootstrap: true
authentication:
  anonymous:
    enabled: false
  webhook:
    enabled: true
  x509:
    clientCAFile: "/etc/kubernetes/cert/ca.pem"
authorization:
  mode: Webhook
registryPullQPS: 0
registryBurst: 20
eventRecordQPS: 0
eventBurst: 20
enableDebuggingHandlers: true
enableContentionProfiling: true
healthzPort: 10248
healthzBindAddress: "##NODE_IP##"
clusterDomain: "${CLUSTER_DNS_DOMAIN}"
clusterDNS:
  - "${CLUSTER_DNS_SVC_IP}"
nodeStatusUpdateFrequency: 10s
nodeStatusReportFrequency: 1m
imageMinimumGCAge: 2m
imageGCHighThresholdPercent: 85
imageGCLowThresholdPercent: 80
volumeStatsAggPeriod: 1m
kubeletCgroups: ""
systemCgroups: ""
cgroupRoot: ""
cgroupsPerQOS: true
cgroupDriver: cgroupfs
runtimeRequestTimeout: 10m
hairpinMode: promiscuous-bridge
maxPods: 220
podCIDR: "${CLUSTER_CIDR}"
podPidsLimit: -1
resolvConf: /etc/resolv.conf
maxOpenFiles: 1000000
kubeAPIQPS: 1000
kubeAPIBurst: 2000
serializeImagePulls: false
evictionHard:
  memory.available:  "100Mi"
  nodefs.available:  "10%"
  nodefs.inodesFree: "5%"
  imagefs.available: "15%"
evictionSoft: {}
enableControllerAttachDetach: true
failSwapOn: true
containerLogMaxSize: 20Mi
containerLogMaxFiles: 10
systemReserved: {}
kubeReserved: {}
systemReservedCgroup: ""
kubeReservedCgroup: ""
enforceNodeAllocatable: ["pods"]
EOF

address：kubelet 安全端口（https，10250）监听的地址，不能为 127.0.0.1，否则 kube-apiserver、heapster 等不能调用 kubelet 的 API；
readOnlyPort=0：关闭只读端口(默认 10255)，等效为未指定；
authentication.anonymous.enabled：设置为 false，不允许匿名访问 10250 端口；
authentication.x509.clientCAFile：指定签名客户端证书的 CA 证书，开启 HTTP 证书认证；
authentication.webhook.enabled=true：开启 HTTPs bearer token 认证；
对于未通过 x509 证书和 webhook 认证的请求(kube-apiserver 或其他客户端)，将被拒绝，提示 Unauthorized；
authroization.mode=Webhook：kubelet 使用 SubjectAccessReview API 查询 kube-apiserver 某 user、group 是否具有操作资源的权限(RBAC)；
featureGates.RotateKubeletClientCertificate、featureGates.RotateKubeletServerCertificate：自动 rotate 证书，证书的有效期取决于 kube-controller-manager 的 --experimental-cluster-signing-duration 参数；
需要 root 账户运行；

2）为各节点创建和分发 kubelet 配置文件

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do 
    echo ">>> ${node_ip}"
    sed -e "s/##NODE_IP##/${node_ip}/" kubelet-config.yaml.template > kubelet-config-${node_ip}.yaml.template
    scp kubelet-config-${node_ip}.yaml.template root@${node_ip}:/etc/kubernetes/kubelet-config.yaml
  done

4、创建和分发 kubelet systemd unit 文件

1）创建 kubelet systemd unit 文件模板

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
cat > kubelet.service.template <<EOF
[Unit]
Description=Kubernetes Kubelet
Documentation=https://github.com/GoogleCloudPlatform/kubernetes
After=docker.service
Requires=docker.service

[Service]
WorkingDirectory=${K8S_DIR}/kubelet
ExecStart=/opt/k8s/bin/kubelet \
  --allow-privileged=true \
  --bootstrap-kubeconfig=/etc/kubernetes/kubelet-bootstrap.kubeconfig \
  --cert-dir=/etc/kubernetes/cert \
  --cni-conf-dir=/etc/cni/net.d \
  --container-runtime=docker \
  --container-runtime-endpoint=unix:///var/run/dockershim.sock \
  --root-dir=${K8S_DIR}/kubelet \
  --kubeconfig=/etc/kubernetes/kubelet.kubeconfig \
  --config=/etc/kubernetes/kubelet-config.yaml \
  --hostname-override=##NODE_NAME## \
  --pod-infra-container-image=registry.cn-beijing.aliyuncs.com/images_k8s/pause-amd64:3.1 \
  --image-pull-progress-deadline=15m \
  --volume-plugin-dir=${K8S_DIR}/kubelet/kubelet-plugins/volume/exec/ \
  --logtostderr=true \
  --v=2
Restart=always
RestartSec=5
StartLimitInterval=0

[Install]
WantedBy=multi-user.target
EOF

+ 如果设置了 `--hostname-override` 选项，则 `kube-proxy` 也需要设置该选项，否则会出现找不到 Node 的情况；
+ `--bootstrap-kubeconfig`：指向 bootstrap kubeconfig 文件，kubelet 使用该文件中的用户名和 token 向 kube-apiserver 发送 TLS Bootstrapping 请求；
+ K8S approve kubelet 的 csr 请求后，在 `--cert-dir` 目录创建证书和私钥文件，然后写入 `--kubeconfig` 文件；
+ `--pod-infra-container-image` 不使用 redhat 的 `pod-infrastructure:latest` 镜像，它不能回收容器的僵尸；

2）为各节点创建和分发 kubelet systemd unit 文件

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_name in ${NODE_NAMES[@]}
  do 
    echo ">>> ${node_name}"
    sed -e "s/##NODE_NAME##/${node_name}/" kubelet.service.template > kubelet-${node_name}.service
    scp kubelet-${node_name}.service root@${node_name}:/etc/systemd/system/kubelet.service
  done

5、Bootstrap Token Auth 和授予权限

kubelet 启动时查找 `--kubeletconfig` 参数对应的文件是否存在，如果不存在则使用 `--bootstrap-kubeconfig` 指定的 kubeconfig 文件向 kube-apiserver 发送证书签名请求 (CSR)。

kube-apiserver 收到 CSR 请求后，对其中的 Token 进行认证，认证通过后将请求的 user 设置为 `system:bootstrap:<Token ID>`，group 设置为 `system:bootstrappers`，这一过程称为 Bootstrap Token Auth。

默认情况下，这个 user 和 group 没有创建 CSR 的权限，kubelet 启动失败，错误日志如下：

$ sudo journalctl -u kubelet -a |grep -A 2 'certificatesigningrequests'
May 26 12:13:41 zhangjun-k8s01 kubelet[128468]: I0526 12:13:41.798230  128468 certificate_manager.go:366] Rotating certificates
May 26 12:13:41 zhangjun-k8s01 kubelet[128468]: E0526 12:13:41.801997  128468 certificate_manager.go:385] Failed while requesting a signed certificate from the master: cannot cre
ate certificate signing request: certificatesigningrequests.certificates.k8s.io is forbidden: User "system:bootstrap:82jfrm" cannot create resource "certificatesigningrequests" i
n API group "certificates.k8s.io" at the cluster scope
May 26 12:13:42 zhangjun-k8s01 kubelet[128468]: E0526 12:13:42.044828  128468 kubelet.go:2244] node "zhangjun-k8s01" not found
May 26 12:13:42 zhangjun-k8s01 kubelet[128468]: E0526 12:13:42.078658  128468 reflector.go:126] k8s.io/kubernetes/pkg/kubelet/kubelet.go:442: Failed to list *v1.Service: Unauthor
ized
May 26 12:13:42 zhangjun-k8s01 kubelet[128468]: E0526 12:13:42.079873  128468 reflector.go:126] k8s.io/kubernetes/pkg/kubelet/kubelet.go:451: Failed to list *v1.Node: Unauthorize
d
May 26 12:13:42 zhangjun-k8s01 kubelet[128468]: E0526 12:13:42.082683  128468 reflector.go:126] k8s.io/client-go/informers/factory.go:133: Failed to list *v1beta1.CSIDriver: Unau
thorized
May 26 12:13:42 zhangjun-k8s01 kubelet[128468]: E0526 12:13:42.084473  128468 reflector.go:126] k8s.io/kubernetes/pkg/kubelet/config/apiserver.go:47: Failed to list *v1.Pod: Unau
thorized
May 26 12:13:42 zhangjun-k8s01 kubelet[128468]: E0526 12:13:42.088466  128468 reflector.go:126] k8s.io/client-go/informers/factory.go:133: Failed to list *v1beta1.RuntimeClass: U
nauthorized

解决办法是：创建一个 clusterrolebinding，将 group system:bootstrappers 和 clusterrole system:node-bootstrapper 绑定：

$ kubectl create clusterrolebinding kubelet-bootstrap --clusterrole=system:node-bootstrapper --group=system:bootstrappers

6、启动 kubelet 服务

source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    ssh root@${node_ip} "mkdir -p ${K8S_DIR}/kubelet/kubelet-plugins/volume/exec/"
    ssh root@${node_ip} "/usr/sbin/swapoff -a"
    ssh root@${node_ip} "systemctl daemon-reload && systemctl enable kubelet && systemctl restart kubelet"
  done

+ 启动服务前必须先创建工作目录；
+ 关闭 swap 分区，否则 kubelet 会启动失败；

$ journalctl -u kubelet |tail
8月 15 12:16:49 zhangjun-k8s01 kubelet[7807]: I0815 12:16:49.578598    7807 feature_gate.go:230] feature gates: &{map[RotateKubeletClientCertificate:true RotateKubeletServerCertificate:true]}
8月 15 12:16:49 zhangjun-k8s01 kubelet[7807]: I0815 12:16:49.578698    7807 feature_gate.go:230] feature gates: &{map[RotateKubeletClientCertificate:true RotateKubeletServerCertificate:true]}
8月 15 12:16:50 zhangjun-k8s01 kubelet[7807]: I0815 12:16:50.205871    7807 mount_linux.go:214] Detected OS with systemd
8月 15 12:16:50 zhangjun-k8s01 kubelet[7807]: I0815 12:16:50.205939    7807 server.go:408] Version: v1.11.2
8月 15 12:16:50 zhangjun-k8s01 kubelet[7807]: I0815 12:16:50.206013    7807 feature_gate.go:230] feature gates: &{map[RotateKubeletClientCertificate:true RotateKubeletServerCertificate:true]}
8月 15 12:16:50 zhangjun-k8s01 kubelet[7807]: I0815 12:16:50.206101    7807 feature_gate.go:230] feature gates: &{map[RotateKubeletServerCertificate:true RotateKubeletClientCertificate:true]}
8月 15 12:16:50 zhangjun-k8s01 kubelet[7807]: I0815 12:16:50.206217    7807 plugins.go:97] No cloud provider specified.
8月 15 12:16:50 zhangjun-k8s01 kubelet[7807]: I0815 12:16:50.206237    7807 server.go:524] No cloud provider specified: "" from the config file: ""
8月 15 12:16:50 zhangjun-k8s01 kubelet[7807]: I0815 12:16:50.206264    7807 bootstrap.go:56] Using bootstrap kubeconfig to generate TLS client cert, key and kubeconfig file
8月 15 12:16:50 zhangjun-k8s01 kubelet[7807]: I0815 12:16:50.208628    7807 bootstrap.go:86] No valid private key and/or certificate found, reusing existing private key or creating a new one

kubelet 启动后使用 --bootstrap-kubeconfig 向 kube-apiserver 发送 CSR 请求，当这个 CSR 被 approve 后，kube-controller-manager 为 kubelet 创建 TLS 客户端证书、私钥和 --kubeletconfig 文件。

注意：kube-controller-manager 需要配置 `--cluster-signing-cert-file` 和 `--cluster-signing-key-file` 参数，才会为 TLS Bootstrap 创建证书和私钥。

TLS bootstrapping相关概念请参考：https://www.cnblogs.com/deny/p/12268224.html

$ kubectl get csr
NAME                                                   AGE       REQUESTOR                 CONDITION
csr-5f4vh   31s   system:bootstrap:82jfrm   Pending
csr-5rw7s   29s   system:bootstrap:b1f7np   Pending
csr-m29fm   31s   system:bootstrap:3gzd53   Pending

$ kubectl get nodes
No resources found.

三个 worker 节点的 csr 均处于 pending 状态；

1）自动 approve CSR 请求

创建三个 ClusterRoleBinding，分别用于自动 approve client、renew client、renew server 证书

cd /opt/k8s/work
cat > csr-crb.yaml <<EOF
 # Approve all CSRs for the group "system:bootstrappers"
 kind: ClusterRoleBinding
 apiVersion: rbac.authorization.k8s.io/v1
 metadata:
   name: auto-approve-csrs-for-group
 subjects:
 - kind: Group
   name: system:bootstrappers
   apiGroup: rbac.authorization.k8s.io
 roleRef:
   kind: ClusterRole
   name: system:certificates.k8s.io:certificatesigningrequests:nodeclient
   apiGroup: rbac.authorization.k8s.io
---
 # To let a node of the group "system:nodes" renew its own credentials
 kind: ClusterRoleBinding
 apiVersion: rbac.authorization.k8s.io/v1
 metadata:
   name: node-client-cert-renewal
 subjects:
 - kind: Group
   name: system:nodes
   apiGroup: rbac.authorization.k8s.io
 roleRef:
   kind: ClusterRole
   name: system:certificates.k8s.io:certificatesigningrequests:selfnodeclient
   apiGroup: rbac.authorization.k8s.io
---
# A ClusterRole which instructs the CSR approver to approve a node requesting a
# serving cert matching its client cert.
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: approve-node-server-renewal-csr
rules:
- apiGroups: ["certificates.k8s.io"]
  resources: ["certificatesigningrequests/selfnodeserver"]
  verbs: ["create"]
---
 # To let a node of the group "system:nodes" renew its own server credentials
 kind: ClusterRoleBinding
 apiVersion: rbac.authorization.k8s.io/v1
 metadata:
   name: node-server-cert-renewal
 subjects:
 - kind: Group
   name: system:nodes
   apiGroup: rbac.authorization.k8s.io
 roleRef:
   kind: ClusterRole
   name: approve-node-server-renewal-csr
   apiGroup: rbac.authorization.k8s.io
EOF
kubectl apply -f csr-crb.yaml

+ auto-approve-csrs-for-group：自动 approve node 的第一次 CSR；注意第一次 CSR 时，请求的 Group 为 system:bootstrappers；
+ node-client-cert-renewal：自动 approve node 后续过期的 client 证书，自动生成的证书 Group 为 system:nodes;
+ node-server-cert-renewal：自动 approve node 后续过期的 server 证书，自动生成的证书 Group 为 system:nodes;

2）查看 kubelet 的情况

等待一段时间(1-10 分钟)，三个节点的 CSR 都被自动 approved：

$ kubectl get csr
NAME                                                   AGE       REQUESTOR                 CONDITION
csr-5f4vh   7m59s   system:bootstrap:82jfrm      Approved,Issued
csr-5r7j7   4m45s   system:node:zhangjun-k8s03   Pending
csr-5rw7s   7m57s   system:bootstrap:b1f7np      Approved,Issued
csr-9snww   6m37s   system:bootstrap:82jfrm      Approved,Issued
csr-c7z56   4m46s   system:node:zhangjun-k8s02   Pending
csr-j55lh   4m46s   system:node:zhangjun-k8s01   Pending
csr-m29fm   7m59s   system:bootstrap:3gzd53      Approved,Issued
csr-rc8w7   6m37s   system:bootstrap:3gzd53      Approved,Issued
csr-vd52r   6m36s   system:bootstrap:b1f7np      Approved,Issued

Pending 的 CSR 用于创建 kubelet server 证书，需要手动 approve，参考后文。

所有节点均 ready：

[root@zhangjun-k8s01 ~]# kubectl get nodes
NAME             STATUS   ROLES    AGE    VERSION
zhangjun-k8s01   Ready    <none>   2d1h   v1.14.2
zhangjun-k8s02   Ready    <none>   2d1h   v1.14.2
zhangjun-k8s03   Ready    <none>   2d1h   v1.14.2

kube-controller-manager 为各 node 生成了 kubeconfig 文件和公私钥：

[root@zhangjun-k8s01 ~]# ls -l /etc/kubernetes/kubelet.kubeconfig
-rw------- 1 root root 2310 2月   3 14:44 /etc/kubernetes/kubelet.kubeconfig
[root@zhangjun-k8s01 ~]# ls -l /etc/kubernetes/cert/|grep kubelet
-rw------- 1 root root 1281 2月   3 14:45 kubelet-client-2020-02-03-14-45-30.pem
lrwxrwxrwx 1 root root   59 2月   3 14:45 kubelet-client-current.pem -> /etc/kubernetes/cert/kubelet-client-2020-02-03-14-45-30.pem
-rw------- 1 root root 1330 2月   3 14:47 kubelet-server-2020-02-03-14-47-02.pem
lrwxrwxrwx 1 root root   59 2月   3 14:47 kubelet-server-current.pem -> /etc/kubernetes/cert/kubelet-server-2020-02-03-14-47-02.pem

没有自动生成 kubelet server 证书；

3）手动 approve server cert csr

基于[安全性考虑](https://kubernetes.io/docs/reference/command-line-tools-reference/kubelet-tls-bootstrapping/#kubelet-configuration)，CSR approving controllers 不会自动 approve kubelet server 证书签名请求，需要手动 approve

$ kubectl get csr
NAME        AGE     REQUESTOR                    CONDITION
csr-5f4vh   9m25s   system:bootstrap:82jfrm      Approved,Issued
csr-5r7j7   6m11s   system:node:zhangjun-k8s03   Pending
csr-5rw7s   9m23s   system:bootstrap:b1f7np      Approved,Issued
csr-9snww   8m3s    system:bootstrap:82jfrm      Approved,Issued
csr-c7z56   6m12s   system:node:zhangjun-k8s02   Pending
csr-j55lh   6m12s   system:node:zhangjun-k8s01   Pending
csr-m29fm   9m25s   system:bootstrap:3gzd53      Approved,Issued
csr-rc8w7   8m3s    system:bootstrap:3gzd53      Approved,Issued
csr-vd52r   8m2s    system:bootstrap:b1f7np      Approved,Issued

$ kubectl certificate approve csr-5r7j7
certificatesigningrequest.certificates.k8s.io/csr-5r7j7 approved

$ kubectl certificate approve csr-c7z56
certificatesigningrequest.certificates.k8s.io/csr-c7z56 approved

$ kubectl certificate approve csr-j55lh
certificatesigningrequest.certificates.k8s.io/csr-j55lh approved

$  ls -l /etc/kubernetes/cert/kubelet-*
-rw------- 1 root root 1281 May 26 12:19 /etc/kubernetes/cert/kubelet-client-2019-05-26-12-19-25.pem
lrwxrwxrwx 1 root root   59 May 26 12:19 /etc/kubernetes/cert/kubelet-client-current.pem -> /etc/kubernetes/cert/kubelet-client-2019-05-26-12-19-25.pem
-rw------- 1 root root 1326 May 26 12:26 /etc/kubernetes/cert/kubelet-server-2019-05-26-12-26-39.pem
lrwxrwxrwx 1 root root   59 May 26 12:26 /etc/kubernetes/cert/kubelet-server-current.pem -> /etc/kubernetes/cert/kubelet-server-2019-05-26-12-26-39.pem

7、kubelet 提供的 API 接口

kubelet 启动后监听多个端口，用于接收 kube-apiserver 或其它客户端发送的请求：

[root@zhangjun-k8s01 ~]# netstat -lnpt|grep kubelet
tcp        0      0 127.0.0.1:46758         0.0.0.0:*               LISTEN      1505/kubelet
tcp        0      0 192.168.1.201:10248     0.0.0.0:*               LISTEN      1505/kubelet
tcp        0      0 192.168.1.201:10250     0.0.0.0:*               LISTEN      1505/kubelet

+ 10248: healthz http 服务；
+ 10250: https 服务，访问该端口时需要认证和授权（即使访问 /healthz 也需要）；
+ 未开启只读端口 10255；
+ 从 K8S v1.10 开始，去除了 `--cadvisor-port` 参数（默认 4194 端口），不支持访问 cAdvisor UI & API。

例如执行 `kubectl exec -it nginx-ds-5rmws -- sh` 命令时，kube-apiserver 会向 kubelet 发送如下请求：

POST /exec/default/nginx-ds-5rmws/my-nginx?command=sh&input=1&output=1&tty=1

kubelet 接收 10250 端口的 https 请求，可以访问如下资源：

+ /pods、/runningpods
+ /metrics、/metrics/cadvisor、/metrics/probes
+ /spec
+ /stats、/stats/container
+ /logs
+ /run/、/exec/, /attach/, /portForward/, /containerLogs/

详情参考：https://github.com/kubernetes/kubernetes/blob/master/pkg/kubelet/server/server.go#L434:3

由于关闭了匿名认证，同时开启了 webhook 授权，所有访问 10250 端口 https API 的请求都需要被认证和授权。

预定义的 ClusterRole system:kubelet-api-admin 授予访问 kubelet 所有 API 的权限(kube-apiserver 使用的 kubernetes 证书 User 授予了该权限)：

[root@zhangjun-k8s01 ~]# kubectl describe clusterrole system:kubelet-api-admin
Name:         system:kubelet-api-admin
Labels:       kubernetes.io/bootstrapping=rbac-defaults
Annotations:  rbac.authorization.kubernetes.io/autoupdate: true
PolicyRule:
  Resources      Non-Resource URLs  Resource Names  Verbs
  ---------      -----------------  --------------  -----
  nodes/log      []                 []              [*]
  nodes/metrics  []                 []              [*]
  nodes/proxy    []                 []              [*]
  nodes/spec     []                 []              [*]
  nodes/stats    []                 []              [*]
  nodes          []                 []              [get list watch proxy]

8、kubelet api 认证和授权

kubelet 配置了如下认证参数：

+ authentication.anonymous.enabled：设置为 false，不允许匿名访问 10250 端口；
+ authentication.x509.clientCAFile：指定签名客户端证书的 CA 证书，开启 HTTPs 证书认证；
+ authentication.webhook.enabled=true：开启 HTTPs bearer token 认证；

同时配置了如下授权参数：

+ authroization.mode=Webhook：开启 RBAC 授权；

kubelet 收到请求后，使用 clientCAFile 对证书签名进行认证，或者查询 bearer token 是否有效。如果两者都没通过，则拒绝请求，提示 Unauthorized：

$ curl -s --cacert /etc/kubernetes/cert/ca.pem https://192.168.1.201:10250/metrics
Unauthorized

$ curl -s --cacert /etc/kubernetes/cert/ca.pem -H "Authorization: Bearer 123456" https://192.168.1.201:10250/metrics
Unauthorized

通过认证后，kubelet 使用 SubjectAccessReview API 向 kube-apiserver 发送请求，查询证书或 token 对应的 user、group 是否有操作资源的权限(RBAC)；

1）证书认证和授权

curl -s --cacert /etc/kubernetes/cert/ca.pem --cert /etc/kubernetes/cert/kube-controller-manager.pem --key /etc/kubernetes/cert/kube-controller-manager-key.pem https://192.168.1.201:10250/metrics

Forbidden (user=system:kube-controller-manager, verb=get, resource=nodes, subresource=metrics)

2）使用部署 kubectl 命令行工具时创建的、具有最高权限的 admin 证书；

curl -s --cacert /etc/kubernetes/cert/ca.pem --cert /opt/k8s/work/admin.pem --key /opt/k8s/work/admin-key.pem https://192.168.1.201:10250/metrics|head

+ `--cacert`、`--cert`、`--key` 的参数值必须是文件路径，如上面的 `./admin.pem` 不能省略 `./`，否则返回 `401 Unauthorized`；

3）bear token 认证和授权

创建一个 ServiceAccount，将它和 ClusterRole system:kubelet-api-admin 绑定，从而具有调用 kubelet API 的权限：

kubectl create sa kubelet-api-test
kubectl create clusterrolebinding kubelet-api-test --clusterrole=system:kubelet-api-admin --serviceaccount=default:kubelet-api-test
SECRET=$(kubectl get secrets | grep kubelet-api-test | awk '{print $1}')
TOKEN=$(kubectl describe secret ${SECRET} | grep -E '^token' | awk '{print $2}')
echo ${TOKEN}

curl -s --cacert /etc/kubernetes/cert/ca.pem -H "Authorization: Bearer ${TOKEN}" https://192.168.1.201:10250/metrics|head

9、cadvisor 和 metrics

cadvisor 是内嵌在 kubelet 二进制中的，统计所在节点各容器的资源(CPU、内存、磁盘、网卡)使用情况的服务。

浏览器访问 https://192.168.1.201:10250/metrics 和 https://192.168.1.201:10250/metrics/cadvisor 分别返回 kubelet 和 cadvisor 的 metrics。

注意：

+ kubelet.config.json 设置 authentication.anonymous.enabled 为 false，不允许匿名证书访问 10250 的 https 服务；
+ 参考浏览器访问 kube-apiserver 安全端口 https://www.cnblogs.com/deny/p/12264757.html，创建和导入相关证书，然后访问上面的 10250 端口；

10、获取 kubelet 的配置

从 kube-apiserver 获取各节点 kubelet 的配置，使用部署 kubectl 命令行工具时创建的、具有最高权限的 admin 证书

curl -sSL --cacert /etc/kubernetes/cert/ca.pem --cert /opt/k8s/work/admin.pem --key /opt/k8s/work/admin-key.pem ${KUBE_APISERVER}/api/v1/nodes/zhangjun-k8s01/proxy/configz | jq  '.kubeletconfig|.kind="KubeletConfiguration"|.apiVersion="kubelet.config.k8s.io/v1beta1"'

kubelet 认证和授权：https://kubernetes.io/docs/reference/command-line-tools-reference/kubelet-authentication-authorization/

五、部署 kube-proxy 组件

1、创建 kube-proxy 证书

1）创建证书签名请求

cd /opt/k8s/work
cat > kube-proxy-csr.json <<EOF
{
  "CN": "system:kube-proxy",
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "CN",
      "ST": "BeiJing",
      "L": "BeiJing",
      "O": "k8s",
      "OU": "4Paradigm"
    }
  ]
}
EOF

+ CN：指定该证书的 User 为 `system:kube-proxy`；
+ 预定义的 RoleBinding `system:node-proxier` 将User `system:kube-proxy` 与 Role `system:node-proxier` 绑定，该 Role 授予了调用 `kube-apiserver` Proxy 相关 API 的权限；
+ 该证书只会被 kube-proxy 当做 client 证书使用，所以 hosts 字段为空；

2）生成证书和私钥

cd /opt/k8s/work
cfssl gencert -ca=/opt/k8s/work/ca.pem 
  -ca-key=/opt/k8s/work/ca-key.pem 
  -config=/opt/k8s/work/ca-config.json 
  -profile=kubernetes  kube-proxy-csr.json | cfssljson -bare kube-proxy
ls kube-proxy*

2、创建和分发 kubeconfig 文件

1）创建文件

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
kubectl config set-cluster kubernetes 
  --certificate-authority=/opt/k8s/work/ca.pem 
  --embed-certs=true 
  --server=${KUBE_APISERVER} 
  --kubeconfig=kube-proxy.kubeconfig

kubectl config set-credentials kube-proxy 
  --client-certificate=kube-proxy.pem 
  --client-key=kube-proxy-key.pem 
  --embed-certs=true 
  --kubeconfig=kube-proxy.kubeconfig

kubectl config set-context default 
  --cluster=kubernetes 
  --user=kube-proxy 
  --kubeconfig=kube-proxy.kubeconfig

kubectl config use-context default --kubeconfig=kube-proxy.kubeconfig

--embed-certs=true`：将 ca.pem 和 admin.pem 证书内容嵌入到生成的 kubectl-proxy.kubeconfig 文件中(不加时，写入的是证书文件路径)；

2）分发 kubeconfig 文件

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_name in ${NODE_NAMES[@]}
  do
    echo ">>> ${node_name}"
    scp kube-proxy.kubeconfig root@${node_name}:/etc/kubernetes/
  done

3、创建 kube-proxy 配置文件

从 v1.10 开始，kube-proxy **部分参数**可以配置文件中配置。可以使用 `--write-config-to` 选项生成该配置文件，或者参考 [源代码的注释](https://github.com/kubernetes/kubernetes/blob/release-1.14/pkg/proxy/apis/config/types.go)。

1）创建 kube-proxy config 文件模板

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
cat > kube-proxy-config.yaml.template <<EOF
kind: KubeProxyConfiguration
apiVersion: kubeproxy.config.k8s.io/v1alpha1
clientConnection:
  burst: 200
  kubeconfig: "/etc/kubernetes/kube-proxy.kubeconfig"
  qps: 100
bindAddress: ##NODE_IP##
healthzBindAddress: ##NODE_IP##:10256
metricsBindAddress: ##NODE_IP##:10249
enableProfiling: true
clusterCIDR: ${CLUSTER_CIDR}
hostnameOverride: ##NODE_NAME##
mode: "ipvs"
portRange: ""
iptables:
  masqueradeAll: false
ipvs:
  scheduler: rr
  excludeCIDRs: []
EOF

+ `bindAddress`: 监听地址；
+ `clientConnection.kubeconfig`: 连接 apiserver 的 kubeconfig 文件；
+ `clusterCIDR`: kube-proxy 根据 `--cluster-cidr` 判断集群内部和外部流量，指定 `--cluster-cidr` 或 `--masquerade-all` 选项后 kube-proxy 才会对访问 Service IP 的请求做 SNAT；
+ `hostnameOverride`: 参数值必须与 kubelet 的值一致，否则 kube-proxy 启动后会找不到该 Node，从而不会创建任何 ipvs 规则；
+ `mode`: 使用 ipvs 模式；

2）为各节点创建和分发 kube-proxy 配置文件

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for (( i=0; i < 3; i++ ))
  do 
    echo ">>> ${NODE_NAMES[i]}"
    sed -e "s/##NODE_NAME##/${NODE_NAMES[i]}/" -e "s/##NODE_IP##/${NODE_IPS[i]}/" kube-proxy-config.yaml.template > kube-proxy-config-${NODE_NAMES[i]}.yaml.template
    scp kube-proxy-config-${NODE_NAMES[i]}.yaml.template root@${NODE_NAMES[i]}:/etc/kubernetes/kube-proxy-config.yaml
  done

4、创建和分发 kube-proxy systemd unit 文件

1）创建模板文件

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
cat > kube-proxy.service <<EOF
[Unit]
Description=Kubernetes Kube-Proxy Server
Documentation=https://github.com/GoogleCloudPlatform/kubernetes
After=network.target

[Service]
WorkingDirectory=${K8S_DIR}/kube-proxy
ExecStart=/opt/k8s/bin/kube-proxy \
  --config=/etc/kubernetes/kube-proxy-config.yaml \
  --logtostderr=true \
  --v=2
Restart=on-failure
RestartSec=5
LimitNOFILE=65536

[Install]
WantedBy=multi-user.target
EOF

2）分发 kube-proxy systemd unit 文件

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_name in ${NODE_NAMES[@]}
  do 
    echo ">>> ${node_name}"
    scp kube-proxy.service root@${node_name}:/etc/systemd/system/
  done

5、启动 kube-proxy 服务

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    ssh root@${node_ip} "mkdir -p ${K8S_DIR}/kube-proxy"
    ssh root@${node_ip} "modprobe ip_vs_rr"
    ssh root@${node_ip} "systemctl daemon-reload && systemctl enable kube-proxy && systemctl restart kube-proxy"
  done

1）检查启动结果

source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    ssh root@${node_ip} "systemctl status kube-proxy|grep Active"
  done

确保状态为 `active (running)`，否则查看日志，确认原因：journalctl -u kube-proxy

2）查看监听端口

[root@zhangjun-k8s01 ~]# netstat -lnpt|grep kube-prox
tcp        0      0 192.168.1.201:10249     0.0.0.0:*               LISTEN      899/kube-proxy
tcp        0      0 192.168.1.201:10256     0.0.0.0:*               LISTEN      899/kube-proxy
tcp6       0      0 :::31424                :::*                    LISTEN      899/kube-proxy
tcp6       0      0 :::31205                :::*                    LISTEN      899/kube-proxy
tcp6       0      0 :::31789                :::*                    LISTEN      899/kube-proxy
[root@zhangjun-k8s01 ~]#

+ 10249：http prometheus metrics port;
+ 10256：http healthz port;

3）查看 ipvs 路由规则

source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    ssh root@${node_ip} "/usr/sbin/ipvsadm -ln"
  done

可见所有通过 https 访问 K8S SVC kubernetes 的请求都转发到 kube-apiserver 节点的 6443 端口