二进制方式部署k8s的master集群

kubernetes master 节点运行如下组件：

+ kube-apiserver
+ kube-scheduler
+ kube-controller-manager
+ kube-nginx

kube-apiserver、kube-scheduler 和 kube-controller-manager 均以多实例模式运行：

kube-scheduler 和 kube-controller-manager 会自动选举产生一个 leader 实例，其它实例处于阻塞模式，当 leader 挂了后，重新选举产生新的 leader，从而保证服务可用性；
kube-apiserver 是无状态的，需要通过 kube-nginx 进行代理访问，从而保证服务可用性；

## 基于 nginx 代理的 kube-apiserver 高可用方案

控制节点的 kube-controller-manager、kube-scheduler 是多实例部署，所以只要有一个实例正常，就可以保证高可用；
集群内的 Pod 使用 K8S 服务域名 kubernetes 访问 kube-apiserver， kube-dns 会自动解析出多个 kube-apiserver 节点的 IP，所以也是高可用的；
在每个节点起一个 nginx 进程，后端对接多个 apiserver 实例，nginx 对它们做健康检查和负载均衡；
kubelet、kube-proxy、controller-manager、scheduler 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；

本章讲解使用 nginx 4 层透明代理功能实现 K8S 节点( master 节点和 worker 节点)高可用访问 kube-apiserver 的步骤。

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

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

etcd集群安装请参考：https://www.cnblogs.com/deny/p/12260025.html

flannel 集群请参考：https://www.cnblogs.com/deny/p/12260072.html

kubectl命令行工具部署请参考：https://www.cnblogs.com/deny/p/12260515.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

一、部署 master 节点

1、下载最新版本二进制文件

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、将二进制文件拷贝到所有 master 节点

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

二、安装配置nginx代理

1、下载安装模板nginx

yum install -y gcc gcc-c++ make
cd /opt/k8s/work
wget http://nginx.org/download/nginx-1.15.3.tar.gz
tar -xzvf nginx-1.15.3.tar.gz
cd /opt/k8s/work/nginx-1.15.3
mkdir nginx-prefix
./configure --with-stream --without-http --prefix=$(pwd)/nginx-prefix --without-http_uwsgi_module --without-http_scgi_module --without-http_fastcgi_module
make && make install

`--with-stream`：开启 4 层透明转发(TCP Proxy)功能；
`--without-xxx`：关闭所有其他功能，这样生成的动态链接二进制程序依赖最小；

查看 nginx 动态链接的库

cd /opt/k8s/work/nginx-1.15.3
ldd ./nginx-prefix/sbin/nginx

由于只开启了 4 层透明转发功能，所以除了依赖 libc 等操作系统核心 lib 库外，没有对其它 lib 的依赖(如 libz、libssl 等)，这样可以方便部署到各版本操作系统中

2、安装和部署 nginx

1）创建目录结构

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 /opt/k8s/kube-nginx/{conf,logs,sbin}"
  done

2）拷贝二进制程序

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 /opt/k8s/kube-nginx/{conf,logs,sbin}"
    scp /opt/k8s/work/nginx-1.15.3/nginx-prefix/sbin/nginx  root@${node_ip}:/opt/k8s/kube-nginx/sbin/kube-nginx
    ssh root@${node_ip} "chmod a+x /opt/k8s/kube-nginx/sbin/*"
  done

重命名二进制文件为 kube-nginx

3）配置 nginx，开启 4 层透明转发功能

cd /opt/k8s/work
cat > kube-nginx.conf << EOF
worker_processes 1;

events {
    worker_connections  1024;
}

stream {
    upstream backend {
        hash $remote_addr consistent;
        server 192.168.1.201:6443        max_fails=3 fail_timeout=30s;
        server 192.168.1.202:6443        max_fails=3 fail_timeout=30s;
        server 192.168.1.203:6443        max_fails=3 fail_timeout=30s;
    }

    server {
        listen 127.0.0.1:8443;
        proxy_connect_timeout 1s;
        proxy_pass backend;
    }
}
EOF

需要根据集群 kube-apiserver 的实际情况，替换 backend 中 server 列表

4）分发配置文件

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    scp kube-nginx.conf  root@${node_ip}:/opt/k8s/kube-nginx/conf/kube-nginx.conf
  done

5）配置 systemd unit 文件，启动服务

配置 kube-nginx systemd unit 文件

cd /opt/k8s/work
cat > kube-nginx.service <<EOF
[Unit]
Description=kube-apiserver nginx proxy
After=network.target
After=network-online.target
Wants=network-online.target

[Service]
Type=forking
ExecStartPre=/opt/k8s/kube-nginx/sbin/kube-nginx -c /opt/k8s/kube-nginx/conf/kube-nginx.conf -p /opt/k8s/kube-nginx -t
ExecStart=/opt/k8s/kube-nginx/sbin/kube-nginx -c /opt/k8s/kube-nginx/conf/kube-nginx.conf -p /opt/k8s/kube-nginx
ExecReload=/opt/k8s/kube-nginx/sbin/kube-nginx -c /opt/k8s/kube-nginx/conf/kube-nginx.conf -p /opt/k8s/kube-nginx -s reload
PrivateTmp=true
Restart=always
RestartSec=5
StartLimitInterval=0
LimitNOFILE=65536

[Install]
WantedBy=multi-user.target
EOF

6）分发 systemd unit 文件

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

7）启动 kube-nginx 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} "systemctl daemon-reload && systemctl enable kube-nginx && systemctl restart kube-nginx"
  done

8）检查 kube-nginx 服务运行状态

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

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

三、部署高可用 kube-apiserver 集群

1、创建 kubernetes 证书和私钥

1）创建证书签名请求

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
cat > kubernetes-csr.json <<EOF
{
  "CN": "kubernetes",
  "hosts": [
    "127.0.0.1",
    "192.168.1.201",
    "192.168.1.202",
    "192.168.1.203",
    "${CLUSTER_KUBERNETES_SVC_IP}",
    "kubernetes",
    "kubernetes.default",
    "kubernetes.default.svc",
    "kubernetes.default.svc.cluster",
    "kubernetes.default.svc.cluster.local."
  ],
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "CN",
      "ST": "BeiJing",
      "L": "BeiJing",
      "O": "k8s",
      "OU": "4Paradigm"
    }
  ]
}
EOF

hosts 字段指定授权使用该证书的 IP 和域名列表，这里列出了 master 节点 IP、kubernetes 服务的 IP 和域名；
kubernetes 服务 IP 是 apiserver 自动创建的，一般是 `--service-cluster-ip-range` 参数指定的网段的第一个IP**，后续可以通过下面命令获取：

kubectl get svc kubernetes

2）生成证书和私钥

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 kubernetes-csr.json | cfssljson -bare kubernetes
ls kubernetes*pem

3）将生成的证书和私钥文件拷贝到所有 master 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/kubernetes/cert"
    scp kubernetes*.pem root@${node_ip}:/etc/kubernetes/cert/
  done

2、创建加密配置文件

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
cat > encryption-config.yaml <<EOF
kind: EncryptionConfig
apiVersion: v1
resources:
  - resources:
      - secrets
    providers:
      - aescbc:
          keys:
            - name: key1
              secret: ${ENCRYPTION_KEY}
      - identity: {}
EOF

将加密配置文件拷贝到 master 节点的 `/etc/kubernetes` 目录下

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

3、创建审计策略文件

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
cat > audit-policy.yaml <<EOF
apiVersion: audit.k8s.io/v1beta1
kind: Policy
rules:
  # The following requests were manually identified as high-volume and low-risk, so drop them.
  - level: None
    resources:
      - group: ""
        resources:
          - endpoints
          - services
          - services/status
    users:
      - 'system:kube-proxy'
    verbs:
      - watch

  - level: None
    resources:
      - group: ""
        resources:
          - nodes
          - nodes/status
    userGroups:
      - 'system:nodes'
    verbs:
      - get

  - level: None
    namespaces:
      - kube-system
    resources:
      - group: ""
        resources:
          - endpoints
    users:
      - 'system:kube-controller-manager'
      - 'system:kube-scheduler'
      - 'system:serviceaccount:kube-system:endpoint-controller'
    verbs:
      - get
      - update

  - level: None
    resources:
      - group: ""
        resources:
          - namespaces
          - namespaces/status
          - namespaces/finalize
    users:
      - 'system:apiserver'
    verbs:
      - get

  # Don't log HPA fetching metrics.
  - level: None
    resources:
      - group: metrics.k8s.io
    users:
      - 'system:kube-controller-manager'
    verbs:
      - get
      - list

  # Don't log these read-only URLs.
  - level: None
    nonResourceURLs:
      - '/healthz*'
      - /version
      - '/swagger*'

  # Don't log events requests.
  - level: None
    resources:
      - group: ""
        resources:
          - events

  # node and pod status calls from nodes are high-volume and can be large, don't log responses for expected updates from nodes
  - level: Request
    omitStages:
      - RequestReceived
    resources:
      - group: ""
        resources:
          - nodes/status
          - pods/status
    users:
      - kubelet
      - 'system:node-problem-detector'
      - 'system:serviceaccount:kube-system:node-problem-detector'
    verbs:
      - update
      - patch

  - level: Request
    omitStages:
      - RequestReceived
    resources:
      - group: ""
        resources:
          - nodes/status
          - pods/status
    userGroups:
      - 'system:nodes'
    verbs:
      - update
      - patch

  # deletecollection calls can be large, don't log responses for expected namespace deletions
  - level: Request
    omitStages:
      - RequestReceived
    users:
      - 'system:serviceaccount:kube-system:namespace-controller'
    verbs:
      - deletecollection

  # Secrets, ConfigMaps, and TokenReviews can contain sensitive & binary data,
  # so only log at the Metadata level.
  - level: Metadata
    omitStages:
      - RequestReceived
    resources:
      - group: ""
        resources:
          - secrets
          - configmaps
      - group: authentication.k8s.io
        resources:
          - tokenreviews
  # Get repsonses can be large; skip them.
  - level: Request
    omitStages:
      - RequestReceived
    resources:
      - group: ""
      - group: admissionregistration.k8s.io
      - group: apiextensions.k8s.io
      - group: apiregistration.k8s.io
      - group: apps
      - group: authentication.k8s.io
      - group: authorization.k8s.io
      - group: autoscaling
      - group: batch
      - group: certificates.k8s.io
      - group: extensions
      - group: metrics.k8s.io
      - group: networking.k8s.io
      - group: policy
      - group: rbac.authorization.k8s.io
      - group: scheduling.k8s.io
      - group: settings.k8s.io
      - group: storage.k8s.io
    verbs:
      - get
      - list
      - watch

  # Default level for known APIs
  - level: RequestResponse
    omitStages:
      - RequestReceived
    resources:
      - group: ""
      - group: admissionregistration.k8s.io
      - group: apiextensions.k8s.io
      - group: apiregistration.k8s.io
      - group: apps
      - group: authentication.k8s.io
      - group: authorization.k8s.io
      - group: autoscaling
      - group: batch
      - group: certificates.k8s.io
      - group: extensions
      - group: metrics.k8s.io
      - group: networking.k8s.io
      - group: policy
      - group: rbac.authorization.k8s.io
      - group: scheduling.k8s.io
      - group: settings.k8s.io
      - group: storage.k8s.io
      
  # Default level for all other requests.
  - level: Metadata
    omitStages:
      - RequestReceived
EOF

2）分发审计策略文件

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    scp audit-policy.yaml root@${node_ip}:/etc/kubernetes/audit-policy.yaml
  done

4、创建后续访问 metrics-server 使用的证书

1）创建证书签名请求

cat > proxy-client-csr.json <<EOF
{
  "CN": "aggregator",
  "hosts": [],
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "CN",
      "ST": "BeiJing",
      "L": "BeiJing",
      "O": "k8s",
      "OU": "4Paradigm"
    }
  ]
}
EOF

CN 名称需要位于 kube-apiserver 的 `--requestheader-allowed-names` 参数中，否则后续访问 metrics 时会提示权限不足

2）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 proxy-client-csr.json | cfssljson -bare proxy-client
ls proxy-client*.pem

3）将生成的证书和私钥文件拷贝到所有 master 节点

source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    scp proxy-client*.pem root@${node_ip}:/etc/kubernetes/cert/
  done

5、创建 kube-apiserver systemd文件

1）创建 kube-apiserver systemd unit 模板文件

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

[Service]
WorkingDirectory=${K8S_DIR}/kube-apiserver
ExecStart=/opt/k8s/bin/kube-apiserver \
  --advertise-address=##NODE_IP## \
  --default-not-ready-toleration-seconds=360 \
  --default-unreachable-toleration-seconds=360 \
  --feature-gates=DynamicAuditing=true \
  --max-mutating-requests-inflight=2000 \
  --max-requests-inflight=4000 \
  --default-watch-cache-size=200 \
  --delete-collection-workers=2 \
  --encryption-provider-config=/etc/kubernetes/encryption-config.yaml \
  --etcd-cafile=/etc/kubernetes/cert/ca.pem \
  --etcd-certfile=/etc/kubernetes/cert/kubernetes.pem \
  --etcd-keyfile=/etc/kubernetes/cert/kubernetes-key.pem \
  --etcd-servers=${ETCD_ENDPOINTS} \
  --bind-address=##NODE_IP## \
  --secure-port=6443 \
  --tls-cert-file=/etc/kubernetes/cert/kubernetes.pem \
  --tls-private-key-file=/etc/kubernetes/cert/kubernetes-key.pem \
  --insecure-port=0 \
  --audit-dynamic-configuration \
  --audit-log-maxage=15 \
  --audit-log-maxbackup=3 \
  --audit-log-maxsize=100 \
  --audit-log-truncate-enabled \
  --audit-log-path=${K8S_DIR}/kube-apiserver/audit.log \
  --audit-policy-file=/etc/kubernetes/audit-policy.yaml \
  --profiling \
  --anonymous-auth=false \
  --client-ca-file=/etc/kubernetes/cert/ca.pem \
  --enable-bootstrap-token-auth \
  --requestheader-allowed-names="aggregator" \
  --requestheader-client-ca-file=/etc/kubernetes/cert/ca.pem \
  --requestheader-extra-headers-prefix="X-Remote-Extra-" \
  --requestheader-group-headers=X-Remote-Group \
  --requestheader-username-headers=X-Remote-User \
  --service-account-key-file=/etc/kubernetes/cert/ca.pem \
  --authorization-mode=Node,RBAC \
  --runtime-config=api/all=true \
  --enable-admission-plugins=NodeRestriction \
  --allow-privileged=true \
  --apiserver-count=3 \
  --event-ttl=168h \
  --kubelet-certificate-authority=/etc/kubernetes/cert/ca.pem \
  --kubelet-client-certificate=/etc/kubernetes/cert/kubernetes.pem \
  --kubelet-client-key=/etc/kubernetes/cert/kubernetes-key.pem \
  --kubelet-https=true \
  --kubelet-timeout=10s \
  --proxy-client-cert-file=/etc/kubernetes/cert/proxy-client.pem \
  --proxy-client-key-file=/etc/kubernetes/cert/proxy-client-key.pem \
  --service-cluster-ip-range=${SERVICE_CIDR} \
  --service-node-port-range=${NODE_PORT_RANGE} \
  --logtostderr=true \
  --v=2
Restart=on-failure
RestartSec=10
Type=notify
LimitNOFILE=65536

[Install]
WantedBy=multi-user.target
EOF

`--advertise-address`：apiserver 对外通告的 IP（kubernetes 服务后端节点 IP）；
`--default-*-toleration-seconds`：设置节点异常相关的阈值；
`--max-*-requests-inflight`：请求相关的最大阈值；
`--etcd-*`：访问 etcd 的证书和 etcd 服务器地址；
`--experimental-encryption-provider-config`：指定用于加密 etcd 中 secret 的配置；
`--bind-address`： https 监听的 IP，不能为 `127.0.0.1`，否则外界不能访问它的安全端口 6443；
`--secret-port`：https 监听端口；
`--insecure-port=0`：关闭监听 http 非安全端口(8080)；
`--tls-*-file`：指定 apiserver 使用的证书、私钥和 CA 文件；
`--audit-*`：配置审计策略和审计日志文件相关的参数；
`--client-ca-file`：验证 client (kue-controller-manager、kube-scheduler、kubelet、kube-proxy 等)请求所带的证书；
`--enable-bootstrap-token-auth`：启用 kubelet bootstrap 的 token 认证；
`--requestheader-*`：kube-apiserver 的 aggregator layer 相关的配置参数，proxy-client & HPA 需要使用；
`--requestheader-client-ca-file`：用于签名 `--proxy-client-cert-file` 和 `--proxy-client-key-file` 指定的证书；在启用了 metric aggregator 时使用；
`--requestheader-allowed-names`：不能为空，值为逗号分割的 `--proxy-client-cert-file` 证书的 CN 名称，这里设置为 "aggregator"；
`--service-account-key-file`：签名 ServiceAccount Token 的公钥文件，kube-controller-manager 的 `--service-account-private-key-file` 指定私钥文件，两者配对使用；
`--runtime-config=api/all=true`：启用所有版本的 APIs，如 autoscaling/v2alpha1；
`--authorization-mode=Node,RBAC`、`--anonymous-auth=false`：开启 Node 和 RBAC 授权模式，拒绝未授权的请求；
`--enable-admission-plugins`：启用一些默认关闭的 plugins；
`--allow-privileged`：运行执行 privileged 权限的容器；
`--apiserver-count=3`：指定 apiserver 实例的数量；
`--event-ttl`：指定 events 的保存时间；
`--kubelet-*`：如果指定，则使用 https 访问 kubelet APIs；需要为证书对应的用户(上面 kubernetes*.pem 证书的用户为 kubernetes) 用户定义 RBAC 规则，否则访问 kubelet API 时提示未授权；
`--proxy-client-*`：apiserver 访问 metrics-server 使用的证书；
`--service-cluster-ip-range`：指定 Service Cluster IP 地址段；
`--service-node-port-range`：指定 NodePort 的端口范围；

如果 kube-apiserver 机器**没有**运行 kube-proxy，则还需要添加 `--enable-aggregator-routing=true` 参数；

注意：
1. requestheader-client-ca-file 指定的 CA 证书，必须具有 client auth and server auth；
2. 如果 `--requestheader-allowed-names` 不为空，且 `--proxy-client-cert-file` 证书的 CN 名称不在 allowed-names 中，则后续查看 node 或 pods 的 metrics 失败，提示：

[root@zhangjun-k8s01 1.8+]# kubectl top nodes
Error from server (Forbidden): nodes.metrics.k8s.io is forbidden: User "aggregator" cannot list resource "nodes" in API group "metrics.k8s.io" at the cluster scope

2）为各节点创建和分发 kube-apiserver systemd unit 文件

替换模板文件中的变量，为各节点生成 systemd unit 文件

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for (( i=0; i < 3; i++ ))
  do
    sed -e "s/##NODE_NAME##/${NODE_NAMES[i]}/" -e "s/##NODE_IP##/${NODE_IPS[i]}/" kube-apiserver.service.template > kube-apiserver-${NODE_IPS[i]}.service 
  done
ls kube-apiserver*.service

NODE_NAMES 和 NODE_IPS 为相同长度的 bash 数组，分别为节点名称和对应的 IP

3）分发生成的 systemd unit 文件

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

文件重命名为 kube-apiserver.service

4）启动 kube-apiserver 服务

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

启动时可能报错，可能是 kube-apiserver 机器没有运行 kube-proxy，则在kube-apiserver.service还需要添加 `--enable-aggregator-routing=true` 参数；

如果不行audit-policy.yaml可改为如下：

# Log all requests at the Metadata level.
apiVersion: audit.k8s.io/v1
kind: Policy
rules:
- level: Metadata

5）检查 kube-apiserver 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 kube-apiserver |grep 'Active:'"
  done

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

6、查看状态

1）打印 kube-apiserver 写入 etcd 的数据

source /opt/k8s/bin/environment.sh
ETCDCTL_API=3 etcdctl 
    --endpoints=${ETCD_ENDPOINTS} 
    --cacert=/opt/k8s/work/ca.pem 
    --cert=/opt/k8s/work/etcd.pem 
    --key=/opt/k8s/work/etcd-key.pem 
    get /registry/ --prefix --keys-only

2）检查集群信息

``` bash
$ kubectl cluster-info
Kubernetes master is running at https://127.0.0.1:8443

To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.

$ kubectl get all --all-namespaces
NAMESPACE   NAME                 TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
default     service/kubernetes   ClusterIP   10.254.0.1   <none>        443/TCP   12m

$ kubectl get componentstatuses
NAME                 STATUS      MESSAGE                                                                                     ERROR
controller-manager   Unhealthy   Get http://127.0.0.1:10252/healthz: dial tcp 127.0.0.1:10252: connect: connection refused
scheduler            Unhealthy   Get http://127.0.0.1:10251/healthz: dial tcp 127.0.0.1:10251: connect: connection refused
etcd-0               Healthy     {"health":"true"}
etcd-2               Healthy     {"health":"true"}
etcd-1               Healthy     {"health":"true"}

1. 如果执行 kubectl 命令式时输出如下错误信息，则说明使用的 `~/.kube/config` 文件不对，请切换到正确的账户后再执行该命令：

`The connection to the server localhost:8080 was refused - did you specify the right host or port?`

2. 执行 `kubectl get componentstatuses` 命令时，apiserver 默认向 127.0.0.1 发送请求。当 controller-manager、scheduler 以集群模式运行时，有可能和 kube-apiserver **不在一台机器**上，这时 controller-manager 或 scheduler 的状态为 Unhealthy，但实际上它们工作**正常**。

3）检查 kube-apiserver 监听的端口

[root@zhangjun-k8s02 work]# netstat -lnpt|grep kube-ap
tcp        0      0 192.168.1.202:6443      0.0.0.0:*               LISTEN      903/kube-apiserver

6443: 接收 https 请求的安全端口，对所有请求做认证和授权；
由于关闭了非安全端口，故没有监听 8080；

7、授予 kube-apiserver 访问 kubelet API 的权限

在执行 kubectl exec、run、logs 等命令时，apiserver 会将请求转发到 kubelet 的 https 端口。这里定义 RBAC 规则，授权 apiserver 使用的证书（kubernetes.pem）用户名（CN：kuberntes）访问 kubelet API 的权限

kubectl create clusterrolebinding kube-apiserver:kubelet-apis --clusterrole=system:kubelet-api-admin --user kubernetes

四、部署高可用 kube-controller-manager 集群

本章介绍部署高可用 kube-controller-manager 集群的步骤。

该集群包含 3 个节点，启动后将通过竞争选举机制产生一个 leader 节点，其它节点为阻塞状态。当 leader 节点不可用时，阻塞的节点将再次进行选举产生新的 leader 节点，从而保证服务的可用性。

为保证通信安全，本文档先生成 x509 证书和私钥，kube-controller-manager 在如下两种情况下使用该证书：

与 kube-apiserver 的安全端口通信;
在**安全端口**(https，10252) 输出 prometheus 格式的 metrics；

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

1、创建 kube-controller-manager 证书和私钥

1）创建证书签名请求

cd /opt/k8s/work
cat > kube-controller-manager-csr.json <<EOF
{
    "CN": "system:kube-controller-manager",
    "key": {
        "algo": "rsa",
        "size": 2048
    },
    "hosts": [
      "127.0.0.1",
      "192.168.1.201",
      "192.168.1.202",
      "192.168.1.203"
    ],
    "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 和 O 均为 `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。

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-controller-manager-csr.json | cfssljson -bare kube-controller-manager
ls kube-controller-manager*pem

3）将生成的证书和私钥分发到所有 master 节点

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

2、创建和分发 kubeconfig 文件

kube-controller-manager 使用 kubeconfig 文件访问 apiserver，该文件提供了 apiserver 地址、嵌入的 CA 证书和 kube-controller-manager 证书：

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-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 到所有 master 节点

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

3、 kube-controller-manager systemd unit配置

1）创建 kube-controller-manager systemd unit 模板文件

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

[Service]
WorkingDirectory=${K8S_DIR}/kube-controller-manager
ExecStart=/opt/k8s/bin/kube-controller-manager \
  --profiling \
  --cluster-name=kubernetes \
  --controllers=*,bootstrapsigner,tokencleaner \
  --kube-api-qps=1000 \
  --kube-api-burst=2000 \
  --leader-elect \
  --use-service-account-credentials\
  --concurrent-service-syncs=2 \
  --bind-address=##NODE_IP## \
  --secure-port=10252 \
  --tls-cert-file=/etc/kubernetes/cert/kube-controller-manager.pem \
  --tls-private-key-file=/etc/kubernetes/cert/kube-controller-manager-key.pem \
  --port=0 \
  --authentication-kubeconfig=/etc/kubernetes/kube-controller-manager.kubeconfig \
  --client-ca-file=/etc/kubernetes/cert/ca.pem \
  --requestheader-allowed-names="" \
  --requestheader-client-ca-file=/etc/kubernetes/cert/ca.pem \
  --requestheader-extra-headers-prefix="X-Remote-Extra-" \
  --requestheader-group-headers=X-Remote-Group \
  --requestheader-username-headers=X-Remote-User \
  --authorization-kubeconfig=/etc/kubernetes/kube-controller-manager.kubeconfig \
  --cluster-signing-cert-file=/etc/kubernetes/cert/ca.pem \
  --cluster-signing-key-file=/etc/kubernetes/cert/ca-key.pem \
  --experimental-cluster-signing-duration=876000h \
  --horizontal-pod-autoscaler-sync-period=10s \
  --concurrent-deployment-syncs=10 \
  --concurrent-gc-syncs=30 \
  --node-cidr-mask-size=24 \
  --service-cluster-ip-range=${SERVICE_CIDR} \
  --pod-eviction-timeout=6m \
  --terminated-pod-gc-threshold=10000 \
  --root-ca-file=/etc/kubernetes/cert/ca.pem \
  --service-account-private-key-file=/etc/kubernetes/cert/ca-key.pem \
  --kubeconfig=/etc/kubernetes/kube-controller-manager.kubeconfig \
  --logtostderr=true \
  --v=2
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target
EOF

`--port=0`：关闭监听非安全端口（http），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；
`--authentication-kubeconfig` 和 `--authorization-kubeconfig`：kube-controller-manager 使用它连接 apiserver，对 client 的请求进行认证和授权。`kube-controller-manager` 不再使用 `--tls-ca-file` 对请求 https metrics 的 Client 证书进行校验。如果没有配置这两个 kubeconfig 参数，则 client 连接 kube-controller-manager https 端口的请求会被拒绝(提示权限不足)。
`--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；
`--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`: kube-controller-manager 中各 controller 使用 serviceaccount 访问 kube-apiserver；

2）为各节点创建和分发 kube-controller-mananger systemd unit 文件

替换模板文件中的变量，为各节点创建 systemd unit 文件

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for (( i=0; i < 3; i++ ))
  do
    sed -e "s/##NODE_NAME##/${NODE_NAMES[i]}/" -e "s/##NODE_IP##/${NODE_IPS[i]}/" kube-controller-manager.service.template > kube-controller-manager-${NODE_IPS[i]}.service 
  done
ls kube-controller-manager*.service

NODE_NAMES 和 NODE_IPS 为相同长度的 bash 数组，分别为节点名称和对应的 IP

3）分发到所有 master 节点

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

文件重命名为 kube-controller-manager.service;

4、启动 kube-controller-manager 服务

source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    ssh root@${node_ip} "mkdir -p ${K8S_DIR}/kube-controller-manager"
    ssh root@${node_ip} "systemctl daemon-reload && systemctl enable kube-controller-manager && systemctl restart kube-controller-manager"
  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 kube-controller-manager|grep Active"
  done

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

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

$ sudo netstat -lnpt | grep kube-cont
tcp        0      0 172.27.137.240:10252    0.0.0.0:*               LISTEN      108977/kube-control

2）查看输出的 metrics

注意：以下命令在 kube-controller-manager 节点上执行

curl -s --cacert /opt/k8s/work/ca.pem --cert /opt/k8s/work/admin.pem --key /opt/k8s/work/admin-key.pem https://192.168.1.201:10252/metrics |head

3）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：

kubectl describe clusterrole system:kube-controller-manager

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。

kubectl get clusterrole|grep controller

以 deployment controller 为例：

kubectl describe clusterrole system:controller:deployment-controller

4）查看当前的 leader

kubectl get endpoints kube-controller-manager --namespace=kube-system  -o yaml

可见，当前的 leader 为 zhangjun-k8s02 节点。

五、部署高可用 kube-scheduler 集群

该集群包含 3 个节点，启动后将通过竞争选举机制产生一个 leader 节点，其它节点为阻塞状态。当 leader 节点不可用后，剩余节点将再次进行选举产生新的 leader 节点，从而保证服务的可用性。

为保证通信安全，本文档先生成 x509 证书和私钥，kube-scheduler 在如下两种情况下使用该证书：

与 kube-apiserver 的安全端口通信;
在**安全端口**(https，10251) 输出 prometheus 格式的 metrics；

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。

1、创建 kube-scheduler 证书和私钥

1）创建证书签名请求

cd /opt/k8s/work
cat > kube-scheduler-csr.json <<EOF
{
    "CN": "system:kube-scheduler",
    "hosts": [
      "127.0.0.1",
      "192.168.1.201",
      "192.168.1.202",
      "192.168.1.203"
    ],
    "key": {
        "algo": "rsa",
        "size": 2048
    },
    "names": [
      {
        "C": "CN",
        "ST": "BeiJing",
        "L": "BeiJing",
        "O": "system:kube-scheduler",
        "OU": "4Paradigm"
      }
    ]
}
EOF

hosts 列表包含**所有** kube-scheduler 节点 IP；
CN 和 O 均为 `system:kube-scheduler`，kubernetes 内置的 ClusterRoleBindings `system:kube-scheduler` 将赋予 kube-scheduler 工作所需的权限；

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-scheduler-csr.json | cfssljson -bare kube-scheduler
ls kube-scheduler*pem

3）将生成的证书和私钥分发到所有 master 节点

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    scp kube-scheduler*.pem root@${node_ip}:/etc/kubernetes/cert/
  done

2、创建和分发 kubeconfig 文件

kube-scheduler 使用 kubeconfig 文件访问 apiserver，该文件提供了 apiserver 地址、嵌入的 CA 证书和 kube-scheduler 证书：

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-scheduler.kubeconfig

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

kubectl config set-context system:kube-scheduler 
  --cluster=kubernetes 
  --user=system:kube-scheduler 
  --kubeconfig=kube-scheduler.kubeconfig

kubectl config use-context system:kube-scheduler --kubeconfig=kube-scheduler.kubeconfig

分发 kubeconfig 到所有 master 节点

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

3、创建 kube-scheduler 配置文件

1）创建模板文件

cd /opt/k8s/work
cat >kube-scheduler.yaml.template <<EOF
apiVersion: kubescheduler.config.k8s.io/v1alpha1
kind: KubeSchedulerConfiguration
bindTimeoutSeconds: 600
clientConnection:
  burst: 200
  kubeconfig: "/etc/kubernetes/kube-scheduler.kubeconfig"
  qps: 100
enableContentionProfiling: false
enableProfiling: true
hardPodAffinitySymmetricWeight: 1
healthzBindAddress: ##NODE_IP##:10251
leaderElection:
  leaderElect: true
metricsBindAddress: ##NODE_IP##:10251
EOF

--kubeconfig`：指定 kubeconfig 文件路径，kube-scheduler 使用它连接和验证 kube-apiserver；
--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；

替换模板文件中的变量：

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for (( i=0; i < 3; i++ ))
  do
    sed -e "s/##NODE_NAME##/${NODE_NAMES[i]}/" -e "s/##NODE_IP##/${NODE_IPS[i]}/" kube-scheduler.yaml.template > kube-scheduler-${NODE_IPS[i]}.yaml
  done
ls kube-scheduler*.yaml

NODE_NAMES 和 NODE_IPS 为相同长度的 bash 数组，分别为节点名称和对应的 IP；

2）分发 kube-scheduler 配置文件到所有 master 节点

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
  do
    echo ">>> ${node_ip}"
    scp kube-scheduler-${node_ip}.yaml root@${node_ip}:/etc/kubernetes/kube-scheduler.yaml
  done

重命名为 kube-scheduler.yaml

4、创建 kube-scheduler systemd unit 文件

1）创建模板文件

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
cat > kube-scheduler.service.template <<EOF
[Unit]
Description=Kubernetes Scheduler
Documentation=https://github.com/GoogleCloudPlatform/kubernetes

[Service]
WorkingDirectory=${K8S_DIR}/kube-scheduler
ExecStart=/opt/k8s/bin/kube-scheduler \
  --config=/etc/kubernetes/kube-scheduler.yaml \
  --bind-address=##NODE_IP## \
  --secure-port=10259 \
  --port=0 \
  --tls-cert-file=/etc/kubernetes/cert/kube-scheduler.pem \
  --tls-private-key-file=/etc/kubernetes/cert/kube-scheduler-key.pem \
  --authentication-kubeconfig=/etc/kubernetes/kube-scheduler.kubeconfig \
  --client-ca-file=/etc/kubernetes/cert/ca.pem \
  --requestheader-allowed-names="" \
  --requestheader-client-ca-file=/etc/kubernetes/cert/ca.pem \
  --requestheader-extra-headers-prefix="X-Remote-Extra-" \
  --requestheader-group-headers=X-Remote-Group \
  --requestheader-username-headers=X-Remote-User \
  --authorization-kubeconfig=/etc/kubernetes/kube-scheduler.kubeconfig \
  --logtostderr=true \
  --v=2
Restart=always
RestartSec=5
StartLimitInterval=0

[Install]
WantedBy=multi-user.target
EOF

2）为各节点创建和分发 kube-scheduler systemd unit 文件

替换模板文件中的变量，为各节点创建 systemd unit 文件：

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for (( i=0; i < 3; i++ ))
  do
    sed -e "s/##NODE_NAME##/${NODE_NAMES[i]}/" -e "s/##NODE_IP##/${NODE_IPS[i]}/" kube-scheduler.service.template > kube-scheduler-${NODE_IPS[i]}.service 
  done
ls kube-scheduler*.service

NODE_NAMES 和 NODE_IPS 为相同长度的 bash 数组，分别为节点名称和对应的 IP

3）分发 systemd unit 文件到所有 master 节点

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

重命名为 kube-scheduler.service

5、启动 kube-scheduler 服务

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

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

2）查看输出的 metrics

注意：以下命令在 kube-scheduler 节点上执行

kube-scheduler 监听 10251 和 10259 端口：

10251：接收 http 请求，非安全端口，不需要认证授权；
10259：接收 https 请求，安全端口，需要认证授权；

两个接口都对外提供 `/metrics` 和 `/healthz` 的访问。

netstat -lnpt |grep kube-sch

curl -s http://192.168.1.201:10251/metrics |head

curl -s --cacert /opt/k8s/work/ca.pem --cert /opt/k8s/work/admin.pem --key /opt/k8s/work/admin-key.pem https://192.168.1.201:10259/metrics |head

3）查看当前的 leader

kubectl get endpoints kube-scheduler --namespace=kube-system  -o yaml

可见，当前的 leader 为 zhangjun-k8s01 节点