二进制安装部署k8s高可用集群V1.20

一、环境准备

1.1、部署k8s的两种方式

1）方式一：kubeadm部署

Kubeadm是一个K8s部署工具，提供kubeadm init和kubeadm join，用于快速部署Kubernetes集群。

2）方式二：二进制软件包

从github下载发行版的二进制包，手动部署每个组件，组成Kubernetes集群

3）两种方式对比

Kubeadm降低部署门槛，但屏蔽了很多细节，遇到问题很难排查。如果想更容易可控，推荐使用二进制包部署Kubernetes集群，虽然手动部署麻烦点，期间可以学习很多工作原理，也利于后期维护

1.2、准备环境

1.2.1、服务器要求

1）建议最小硬件配置：2核CPU、2G内存、30G硬盘

2）服务器最好可以访问外网，会有从网上拉取镜像需求，如果服务器不能上网，需要提前下载对应镜像并导入节点

1.2.2、软件环境

软件	版本
操作系统	CentOS7.x_x64
容器引擎	Docker CE 19
Kubernetes	Kubernetes v1.20

1.2.3、服务器整体规划 

角色	IP	组件
k8s-master1	172.17.87.0	kube-apiserver，kube-controller-manager，kube-scheduler，kubelet，kube-proxy，docker，etcd，nginx，keepalived
k8s-master2	172.17.87.1	kube-apiserver，kube-controller-manager，kube-scheduler，kubelet，kube-proxy，docker，etcd，nginx，keepalived
k8s-master3	172.17.87.2	kube-apiserver，kube-controller-manager，kube-scheduler，kubelet，kube-proxy，docker，etcd，nginx，keepalived
k8s-node1	172.17.87.3	kubelet，kube-proxy，docker
k8s-node2	172.17.86.255	kubelet，kube-proxy，docker
k8s-node3	172.17.86.254	kubelet，kube-proxy，docker
负载均衡器IP	10.0.0.88 (VIP)	虚拟VIP，可填写任意地址，由keepalived生成，建议与小编保持一致

搭建这套K8s高可用集群分两部分实施，先部署一套单Master架构（3台），再扩容为多Master架构（4台或6台）

单Master架构图：

单Master服务器规划：

角色	IP	组件
k8s-master1	172.17.87.0	kube-apiserver，kube-controller-manager，kube-scheduler，etcd（k8s-master1，k8s-master2, k8s-master3），kubelet，kube-proxy，docker
k8s-node1	172.17.87.3	kubelet，kube-proxy，docker
k8s-node2	172.17.86.255	kubelet，kube-proxy，docker

1.2.4、节点访问免密设置（只在k8s-master1执行 ）

目标：实现 k8s-master1 到集群内任意节点免密访问

cd /root/.ssh/

ssh-keygen -t rsa -b 2048

# 此处，手动粘贴密码即可
for i in  k8s-master2 k8s-master3 k8s-node1 k8s-node2 k8s-node3;do ssh-copy-id -p 22 root@$i  ;done

1.2.5、操作系统初始化配置（所有节点执行）

# 1、关闭防火墙 
systemctl stop firewalld 
systemctl disable firewalld 
 
# 2、关闭selinux 
sed -i 's/enforcing/disabled/' /etc/selinux/config  # 永久 
setenforce 0  # 临时 
 
# 3、关闭swap 
swapoff -a  # 临时 
sed -ri 's/.*swap.*/#&/' /etc/fstab    # 永久 
 

# 5、在master添加hosts 
cat >> /etc/hosts << EOF 
172.17.87.0  k8s-master1
172.17.87.1 k8s-master2
172.17.87.2 k8s-master3
172.17.87.3 k8s-node1
172.17.86.255 k8s-node2
172.17.86.254 k8s-node3
EOF

# 5、根据规划设置主机名 
hostnamectl set-hostname  
bash
 
# 6、将桥接的IPv4流量传递到iptables的链 
cat > /etc/sysctl.d/k8s.conf << EOF 
net.bridge.bridge-nf-call-ip6tables = 1 
net.bridge.bridge-nf-call-iptables = 1 
EOF 
sysctl --system  # 生效 
 
# 7、时间同步 
yum install ntpdate -y 
ntpdate time.windows.com

1.3、证书说明

k8s集群需要用到很多证书，先将证书做一个简单的说明：

二、部署Etcd集群

Etcd 是一个分布式键值存储系统，Kubernetes使用Etcd进行数据存储，所以先准备一个Etcd数据库，为解决Etcd单点故障，应采用集群方式部署，这里使用3台组建集群，可容忍1台机器故障，当然，你也可以使用5台组建集群，可容忍2台机器故障。

节点名称	IP
etcd-1	172.17.87.0
etcd-2	172.17.87.1
etcd-3	172.17.87.2

注：为了节省机器，这里与K8s-master1、K8s-master2，K8s-master3 机器复用。也可以独立于k8s集群之外部署，只要apiserver能连接到就行

2.1、准备cfssl证书生成工具

cfssl是一个开源的证书管理工具，使用json文件生成证书，相比openssl更方便使用。找任意一台服务器操作，这里用K8s-master1节点

# 下载软件包
mkdir cfssl && cd cfssl/
wget https://pkg.cfssl.org/R1.2/cfssl_linux-amd64
wget https://pkg.cfssl.org/R1.2/cfssljson_linux-amd64
wget https://pkg.cfssl.org/R1.2/cfssl-certinfo_linux-amd64
chmod +x cfssl_linux-amd64 cfssljson_linux-amd64 cfssl-certinfo_linux-amd64
mv cfssl_linux-amd64 /usr/local/bin/cfssl
mv cfssljson_linux-amd64 /usr/local/bin/cfssljson
mv cfssl-certinfo_linux-amd64 /usr/bin/cfssl-certinfo

2.2、生成Etcd证书

2.2.1、自签证书颁发机构（CA）

在线json格式校验 https://www.bejson.com/

# 1、创建工作目录
mkdir -p ~/TLS/{etcd,k8s} && cd ~/TLS/etcd

# 2、自签CA
cat > ca-config.json << EOF
{
  "signing": {
    "default": {
      "expiry": "87600h"
    },
    "profiles": {
      "www": {
         "expiry": "87600h",
         "usages": [
            "signing",
            "key encipherment",
            "server auth",
            "client auth"
        ]
      }
    }
  }
}
EOF

cat > ca-csr.json << EOF
{
    "CN": "etcd CA",
    "key": {
        "algo": "rsa",
        "size": 2048
    },
    "names": [
        {
            "C": "CN",
            "L": "Beijing",
            "ST": "Beijing"
        }
    ]
}
EOF

# 3、生成证书：会生成ca.pem和ca-key.pem文件
cfssl gencert -initca ca-csr.json | cfssljson -bare ca -

2.2.2、使用自签CA签发Etcd Https证书

# 创建证书请求文件
cat > server-csr.json << EOF
{
    "CN": "etcd",
    "hosts": [
    "172.17.87.0",
    "172.17.87.1",
    "172.17.87.2"
    ],
    "key": {
        "algo": "rsa",
        "size": 2048
    },
    "names": [
        {
            "C": "CN",
            "L": "BeiJing",
            "ST": "BeiJing"
        }
    ]
}
EOF

注：上述文件hosts字段中IP为所有etcd节点的集群内部通信IP（k8s-master1，k8s-master2，k8s-master3的IP，替换为自己的），一个都不能少！为了方便后期扩容可以多写几个预留的IP。

# 生成证书，会生成server.pem和server-key.pem文件
cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=www server-csr.json | cfssljson -bare server

2.3、部署Etcd集群（在k8s-master1，k8s-master2，k8s-master3执行）

1）下载etcd二进制文件

地址：https://github.com/etcd-io/etcd/releases/download/v3.4.9/etcd-v3.4.9-linux-amd64.tar.gz

2）创建工作目录并解压二进制包

cd ~/TLS/etcd
wget ​https://github.com/etcd-io/etcd/releases/download/v3.4.9/etcd-v3.4.9-linux-amd64.tar.gz​

mkdir /opt/etcd/{bin,cfg,ssl} -p

tar zxvf etcd-v3.4.9-linux-amd64.tar.gz
mv etcd-v3.4.9-linux-amd64/{etcd,etcdctl} /opt/etcd/bin/

3）创建etcd配置文件（以k8s-master1 172.17.87.0为例）

cat > /opt/etcd/cfg/etcd.conf << EOF
#[Member]
ETCD_NAME="etcd-1"
ETCD_DATA_DIR="/var/lib/etcd/default.etcd"
ETCD_LISTEN_PEER_URLS="https://172.17.87.0:2380"
ETCD_LISTEN_CLIENT_URLS="https://172.17.87.0:2379"

#[Clustering]
ETCD_INITIAL_ADVERTISE_PEER_URLS="https://172.17.87.0:2380"
ETCD_ADVERTISE_CLIENT_URLS="https://172.17.87.0:2379"
ETCD_INITIAL_CLUSTER="etcd-1=https://172.17.87.0:2380,etcd-2=https://172.17.87.1:2380,etcd-3=https://172.17.87.2:2380"
ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
ETCD_INITIAL_CLUSTER_STATE="new"
EOF

配置文件说明：

ETCD_NAME：节点名称，集群中唯一

ETCD_DATA_DIR：数据目录

ETCD_LISTEN_PEER_URLS：集群通信监听地址

ETCD_LISTEN_CLIENT_URLS：客户端访问监听地址

ETCD_INITIAL_ADVERTISE_PEERURLS：集群通告地址

ETCD_ADVERTISE_CLIENT_URLS：客户端通告地址

ETCD_INITIAL_CLUSTER：集群节点地址

ETCD_INITIALCLUSTER_TOKEN：集群Token

ETCD_INITIALCLUSTER_STATE：加入集群的当前状态，new是新集群，existing表示加入已有集群

4）systemd管理etcd

cat > /usr/lib/systemd/system/etcd.service << EOF
[Unit]
Description=Etcd Server
After=network.target
After=network-online.target
Wants=network-online.target

[Service]
Type=notify
EnvironmentFile=/opt/etcd/cfg/etcd.conf
ExecStart=/opt/etcd/bin/etcd \
--cert-file=/opt/etcd/ssl/server.pem \
--key-file=/opt/etcd/ssl/server-key.pem \
--peer-cert-file=/opt/etcd/ssl/server.pem \
--peer-key-file=/opt/etcd/ssl/server-key.pem \
--trusted-ca-file=/opt/etcd/ssl/ca.pem \
--peer-trusted-ca-file=/opt/etcd/ssl/ca.pem \
--logger=zap
Restart=on-failure
LimitNOFILE=65536

[Install]
WantedBy=multi-user.target
EOF

5）拷贝生成的证书至指定位置

# 把刚才生成的证书拷贝到配置文件中的路径
cp ~/TLS/etcd/ca*pem ~/TLS/etcd/server*pem /opt/etcd/ssl/

6）启动并设置开机启动

systemctl daemon-reload
systemctl start etcd
systemctl enable etcd
systemctl status etcd

注意：此时启动一台etcd（k8s-master1）会显示hang住，这是再等待其他两个节点（k8s-master2，k8s-master3）启动，可以查看日志/var/log/messages

7）将 k8s-master1 节点所有生成的文件拷贝到 k8s-master2 和 k8s-master3

scp -r /opt/etcd/ root@k8s-master2:/opt/etcd/
scp /usr/lib/systemd/system/etcd.service root@k8s-master2:/usr/lib/systemd/system/

scp -r /opt/etcd/ root@k8s-master3:/opt/etcd/
scp /usr/lib/systemd/system/etcd.service root@k8s-master3:/usr/lib/systemd/system/

8）在 k8s-master2 和 k8s-master3 分别修改etcd.conf配置文件中的节点名称和当前服务器IP

vim /opt/etcd/cfg/etcd.conf

#[Member]
ETCD_NAME="etcd-1"   # 修改此处，节点2改为etcd-2，节点3改为etcd-3
ETCD_DATA_DIR="/var/lib/etcd/default.etcd"
ETCD_LISTEN_PEER_URLS="https://172.17.87.0:2380"   # 修改此处为当前服务器IP
ETCD_LISTEN_CLIENT_URLS="https://172.17.87.0:2379" # 修改此处为当前服务器IP

#[Clustering]
ETCD_INITIAL_ADVERTISE_PEER_URLS="https://172.17.87.0:2380" # 修改此处为当前服务器IP
ETCD_ADVERTISE_CLIENT_URLS="https://172.17.87.0:2379" # 修改此处为当前服务器IP
ETCD_INITIAL_CLUSTER="etcd-1=https://172.17.87.0:2380,etcd-2=https://172.17.87.1:2380,etcd-3=https://172.17.87.2:2380"
ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
ETCD_INITIAL_CLUSTER_STATE="new"

9）启动etcd并设置开机启动

systemctl daemon-reload
systemctl start etcd
systemctl enable etcd

10）查看集群状态

ETCDCTL_API=3 /opt/etcd/bin/etcdctl --cacert=/opt/etcd/ssl/ca.pem --cert=/opt/etcd/ssl/server.pem --key=/opt/etcd/ssl/server-key.pem --endpoints="https://172.17.87.0:2379,https://172.17.87.1:2379,https://172.17.87.2:2379" endpoint health --write-out=table

# 显示结果如下，说明部署成功
+--------------------------+--------+------------+-------+
|         ENDPOINT         | HEALTH |    TOOK    | ERROR |
+--------------------------+--------+------------+-------+
| https://172.17.87.1:2379 |   true |  8.57318ms |       |
| https://172.17.87.0:2379 |   true | 8.398224ms |       |
| https://172.17.87.2:2379 |   true | 8.704974ms |       |
+--------------------------+--------+------------+-------+

如果有问题第一步先看日志：/var/log/message 或 journalctl -u etcd

三、安装docker(所有节点执行)

这里使用Docker作为容器引擎，也可以换成别的，例如containerd

下载地址：https://download.docker.com/linux/static/stable/x86_64/docker-19.03.9.tgz

以下在所有节点操作。这里采用二进制安装，用yum安装也一样。

1）解压二进制软件包

wget https://download.docker.com/linux/static/stable/x86_64/docker-19.03.9.tgz
tar zxvf docker-19.03.9.tgz
mv docker/* /usr/bin
docker version

2）systemd管理docker

cat > /usr/lib/systemd/system/docker.service << EOF
[Unit]
Description=Docker Application Container Engine
Documentation=https://docs.docker.com
After=network-online.target firewalld.service
Wants=network-online.target

[Service]
Type=notify
ExecStart=/usr/bin/dockerd
ExecReload=/bin/kill -s HUP $MAINPID
LimitNOFILE=infinity
LimitNPROC=infinity
LimitCORE=infinity
TimeoutStartSec=0
Delegate=yes
KillMode=process
Restart=on-failure
StartLimitBurst=3
StartLimitInterval=60s

[Install]
WantedBy=multi-user.target
EOF

3）启动并设置开机启动

systemctl daemon-reload
systemctl start docker
systemctl enable docker
systemctl status docker

四、部署Master Node(在k8s-master1执行)

4.1、部署kube-apiserver

4.1.1、自签证书签发机构（CA）

cd ~/TLS/k8s

cat > ca-config.json << EOF
{
  "signing": {
    "default": {
      "expiry": "87600h"
    },
    "profiles": {
      "kubernetes": {
         "expiry": "87600h",
         "usages": [
            "signing",
            "key encipherment",
            "server auth",
            "client auth"
        ]
      }
    }
  }
}
EOF
cat > ca-csr.json << EOF
{
    "CN": "kubernetes",
    "key": {
        "algo": "rsa",
        "size": 2048
    },
    "names": [
        {
            "C": "CN",
            "L": "Beijing",
            "ST": "Beijing",
            "O": "k8s",
            "OU": "System"
        }
    ]
}
EOF

# 生成证书：生成ca.pem和ca-key.pem文件
cfssl gencert -initca ca-csr.json | cfssljson -bare ca -

4.1.2、使用自签CA签发kube-apiserver HTTPS证书

# 创建证书请求文件
cat > server-csr.json << EOF
{
    "CN": "kubernetes",
    "hosts": [
      "10.0.0.1",
      "127.0.0.1",
      "172.17.87.0",
      "172.17.87.1",
      "172.17.87.2",
      "172.17.87.3",
      "172.17.86.255",
      "172.17.86.254",
      "10.0.0.88",
      "kubernetes",
      "kubernetes.default",
      "kubernetes.default.svc",
      "kubernetes.default.svc.cluster",
      "kubernetes.default.svc.cluster.local"
    ],
    "key": {
        "algo": "rsa",
        "size": 2048
    },
    "names": [
        {
            "C": "CN",
            "L": "BeiJing",
            "ST": "BeiJing",
            "O": "k8s",
            "OU": "System"
        }
    ]
}
EOF

注意：上述文件hosts字段中IP为集群内所有节点（k8s-master1，k8s-master2，k8s-master3，k8s-node1，k8s-node2，k8s-node3），10.0.0.1供未来coredns使用；127.0.0.1供本机使用；10.0.0.88未来搭建keepalived使用虚拟VIP，一个都不能少！为了方便后期扩容可以多写几个预留的IP

# 生成证书，生成server.pem和server-key.pem
cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=kubernetes server-csr.json | cfssljson -bare server

4.1.3、部署kube-apiserver步骤

官网：https://github.com/kubernetes/kubernetes
目录：master/CHANGELOG/CHANGELOG-1.20.md/Server Binaries

地址：kubernetes/CHANGELOG-1.20.md at master · kubernetes/kubernetes · GitHub

注：打开链接你会发现里面有很多包，下载一个server包就够了，包含了Master和Worker Node二进制文件

下载：https://dl.k8s.io/v1.20.0/kubernetes-server-linux-amd64.tar.gz (不用执行)

1）下载并解压二进制软件包

cd /root/TLS/k8s

wget https://dl.k8s.io/v1.20.0/kubernetes-server-linux-amd64.tar.gz

mkdir -p /opt/kubernetes/{bin,cfg,ssl,logs}
 
tar zxvf kubernetes-server-linux-amd64.tar.gz

cd kubernetes/server/bin
cp kube-apiserver kube-scheduler kube-controller-manager /opt/kubernetes/bin
cp kubectl /usr/bin/

2）创建配置文件

cat > /opt/kubernetes/cfg/kube-apiserver.conf << EOF
KUBE_APISERVER_OPTS="--logtostderr=false \\
--v=2 \\
--log-dir=/opt/kubernetes/logs \\
--etcd-servers=https://172.17.87.0:2379,https://172.17.87.1:2379,https://172.17.87.2:2379 \\
--bind-address=172.17.87.0 \\
--secure-port=6443 \\
--advertise-address=172.17.87.0 \\
--allow-privileged=true \\
--service-cluster-ip-range=10.0.0.0/24 \\
--enable-admission-plugins=NamespaceLifecycle,LimitRanger,ServiceAccount,ResourceQuota,NodeRestriction \\
--authorization-mode=RBAC,Node \\
--enable-bootstrap-token-auth=true \\
--token-auth-file=/opt/kubernetes/cfg/token.csv \\
--service-node-port-range=30000-32767 \\
--kubelet-client-certificate=/opt/kubernetes/ssl/server.pem \\
--kubelet-client-key=/opt/kubernetes/ssl/server-key.pem \\
--tls-cert-file=/opt/kubernetes/ssl/server.pem  \\
--tls-private-key-file=/opt/kubernetes/ssl/server-key.pem \\
--client-ca-file=/opt/kubernetes/ssl/ca.pem \\
--service-account-key-file=/opt/kubernetes/ssl/ca-key.pem \\
--service-account-issuer=api \\
--service-account-signing-key-file=/opt/kubernetes/ssl/server-key.pem \\
--etcd-cafile=/opt/etcd/ssl/ca.pem \\
--etcd-certfile=/opt/etcd/ssl/server.pem \\
--etcd-keyfile=/opt/etcd/ssl/server-key.pem \\
--requestheader-client-ca-file=/opt/kubernetes/ssl/ca.pem \\
--proxy-client-cert-file=/opt/kubernetes/ssl/server.pem \\
--proxy-client-key-file=/opt/kubernetes/ssl/server-key.pem \\
--requestheader-allowed-names=kubernetes \\
--requestheader-extra-headers-prefix=X-Remote-Extra- \\
--requestheader-group-headers=X-Remote-Group \\
--requestheader-username-headers=X-Remote-User \\
--enable-aggregator-routing=true \\
--audit-log-maxage=30 \\
--audit-log-maxbackup=3 \\
--audit-log-maxsize=100 \\
--audit-log-path=/opt/kubernetes/logs/k8s-audit.log"
EOF

注：上面两个\ \ 第一个是转义符，第二个是换行符，使用转义符是为了使用EOF保留换行符

参数说明：

--logtostderr：启用日志

--v：日志等级

--log-dir：日志目录

--etcd-servers：etcd集群地址

--bind-address：监听地址

--secure-port：https安全端口

--advertise-address：集群通告地址

--allow-privileged：启用授权

--service-cluster-ip-range：Service虚拟IP地址段

--enable-admission-plugins：准入控制模块

--authorization-mode：认证授权，启用RBAC授权和节点自管理

--enable-bootstrap-token-auth：启用TLS bootstrap机制

--token-auth-file：bootstrap token文件

--service-node-port-range：Service nodeport类型默认分配端口范围

--kubelet-client-xxx：apiserver访问kubelet客户端证书

--tls-xxx-file：apiserver https证书

1.20版本必须加的参数：--service-account-issuer，--service-account-signing-key-file

--etcd-xxxfile：连接Etcd集群证书

--audit-log-xxx：审计日志

启动聚合层相关配置：--requestheader-client-ca-file，--proxy-client-cert-file，--proxy-client-key-file，--requestheader-allowed-names，--requestheader-extra-headers-prefix，--requestheader-group-headers，--requestheader-username-headers，--enable-aggregator-routing

3）拷贝生成的证书

# 把刚才生成的证书拷贝到配置文件中的路径
cp ~/TLS/k8s/ca*pem ~/TLS/k8s/server*pem /opt/kubernetes/ssl/

4）启用 TLS Bootstrapping 机制

TLS Bootstraping：Master apiserver启用TLS认证后，Node节点kubelet和kube-proxy要与kube-apiserver进行通信，必须使用CA签发的有效证书才可以，当Node节点很多时，这种客户端证书颁发需要大量工作，同样也会增加集群扩展复杂度。为了简化流程，Kubernetes引入了TLS bootstraping机制来自动颁发客户端证书，kubelet会以一个低权限用户自动向apiserver申请证书，kubelet的证书由apiserver动态签署。所以强烈建议在Node上使用这种方式，目前主要用于kubelet，kube-proxy还是由我们统一颁发一个证书。

TLS bootstraping 工作流程：

5）创建token文件

# 格式：token，用户名，UID，用户组
cat > /opt/kubernetes/cfg/token.csv << EOF
c47ffb939f5ca36231d9e3121a252940,kubelet-bootstrap,10001,"system:node-bootstrapper"
EOF

token也可自行生成替换：

head -c 16 /dev/urandom | od -An -t x | tr -d ' '

6）systemd管理apiserver

cat > /usr/lib/systemd/system/kube-apiserver.service << EOF
[Unit]
Description=Kubernetes API Server
Documentation=https://github.com/kubernetes/kubernetes

[Service]
EnvironmentFile=/opt/kubernetes/cfg/kube-apiserver.conf
ExecStart=/opt/kubernetes/bin/kube-apiserver \$KUBE_APISERVER_OPTS
Restart=on-failure

[Install]
WantedBy=multi-user.target
EOF

7）启动并设置开机启动

systemctl daemon-reload
systemctl start kube-apiserver 
systemctl enable kube-apiserver
systemctl status kube-apiserver

4.2、部署kube-controller-manager

1）创建配置文件

cat > /opt/kubernetes/cfg/kube-controller-manager.conf << EOF
KUBE_CONTROLLER_MANAGER_OPTS="--logtostderr=false \\
--v=2 \\
--log-dir=/opt/kubernetes/logs \\
--leader-elect=true \\
--kubeconfig=/opt/kubernetes/cfg/kube-controller-manager.kubeconfig \\
--bind-address=127.0.0.1 \\
--allocate-node-cidrs=true \\
--cluster-cidr=10.244.0.0/16 \\
--service-cluster-ip-range=10.0.0.0/24 \\
--cluster-signing-cert-file=/opt/kubernetes/ssl/ca.pem \\
--cluster-signing-key-file=/opt/kubernetes/ssl/ca-key.pem  \\
--root-ca-file=/opt/kubernetes/ssl/ca.pem \\
--service-account-private-key-file=/opt/kubernetes/ssl/ca-key.pem \\
--cluster-signing-duration=87600h0m0s"
EOF

配置说明：

--kubeconfig：连接apiserver配置文件

--leader-elect：当该组件启动多个时，自动选举（HA）

--cluster-signing-cert-file/--cluster-signing-key-file：自动为kubelet颁发证书的CA，与apiserver保持一致

2）生成kubeconfig文件

生成kube-controller-manager证书：

# 切换工作目录
cd ~/TLS/k8s

# 创建证书请求文件
cat > kube-controller-manager-csr.json << EOF
{
  "CN": "system:kube-controller-manager",
  "hosts": [],
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "CN",
      "L": "BeiJing", 
      "ST": "BeiJing",
      "O": "system:masters",
      "OU": "System"
    }
  ]
}
EOF

# 生成证书
cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=kubernetes kube-controller-manager-csr.json | cfssljson -bare kube-controller-manager

生成kubeconfig文件（以下是shell命令，直接在终端执行）：

KUBE_CONFIG="/opt/kubernetes/cfg/kube-controller-manager.kubeconfig"
KUBE_APISERVER="https://172.17.87.0:6443"

kubectl config set-cluster kubernetes \
  --certificate-authority=/opt/kubernetes/ssl/ca.pem \
  --embed-certs=true \
  --server=${KUBE_APISERVER} \
  --kubeconfig=${KUBE_CONFIG}
kubectl config set-credentials kube-controller-manager \
  --client-certificate=./kube-controller-manager.pem \
  --client-key=./kube-controller-manager-key.pem \
  --embed-certs=true \
  --kubeconfig=${KUBE_CONFIG}
kubectl config set-context default \
  --cluster=kubernetes \
  --user=kube-controller-manager \
  --kubeconfig=${KUBE_CONFIG}
kubectl config use-context default --kubeconfig=${KUBE_CONFIG}

3）systemd管理controller-manager

cat > /usr/lib/systemd/system/kube-controller-manager.service << EOF
[Unit]
Description=Kubernetes Controller Manager
Documentation=https://github.com/kubernetes/kubernetes

[Service]
EnvironmentFile=/opt/kubernetes/cfg/kube-controller-manager.conf
ExecStart=/opt/kubernetes/bin/kube-controller-manager \$KUBE_CONTROLLER_MANAGER_OPTS
Restart=on-failure

[Install]
WantedBy=multi-user.target
EOF

4）启动并设置开机启动

systemctl daemon-reload
systemctl start kube-controller-manager
systemctl enable kube-controller-manager
systemctl status kube-controller-manager

4.3、部署kube-scheduler

1）创建配置文件

cat > /opt/kubernetes/cfg/kube-scheduler.conf << EOF
KUBE_SCHEDULER_OPTS="--logtostderr=false \\
--v=2 \\
--log-dir=/opt/kubernetes/logs \\
--leader-elect \\
--kubeconfig=/opt/kubernetes/cfg/kube-scheduler.kubeconfig \\
--bind-address=127.0.0.1"
EOF

参数说明：

--kubeconfig：连接apiserver配置文件

--leader-elect：当该组件启动多个时，自动选举（HA）

2）生成kubeconfig文件

生成kube-scheduler证书：

# 切换工作目录
cd ~/TLS/k8s

# 创建证书请求文件
cat > kube-scheduler-csr.json << EOF
{
  "CN": "system:kube-scheduler",
  "hosts": [],
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "CN",
      "L": "BeiJing",
      "ST": "BeiJing",
      "O": "system:masters",
      "OU": "System"
    }
  ]
}
EOF

# 生成证书
cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=kubernetes kube-scheduler-csr.json | cfssljson -bare kube-scheduler

生成kubeconfig文件（以下是shell命令，直接在终端执行）：

KUBE_CONFIG="/opt/kubernetes/cfg/kube-scheduler.kubeconfig"
KUBE_APISERVER="https://172.17.87.0:6443"

kubectl config set-cluster kubernetes \
  --certificate-authority=/opt/kubernetes/ssl/ca.pem \
  --embed-certs=true \
  --server=${KUBE_APISERVER} \
  --kubeconfig=${KUBE_CONFIG}
kubectl config set-credentials kube-scheduler \
  --client-certificate=./kube-scheduler.pem \
  --client-key=./kube-scheduler-key.pem \
  --embed-certs=true \
  --kubeconfig=${KUBE_CONFIG}
kubectl config set-context default \
  --cluster=kubernetes \
  --user=kube-scheduler \
  --kubeconfig=${KUBE_CONFIG}
kubectl config use-context default --kubeconfig=${KUBE_CONFIG}

3）systemd管理scheduler

cat > /usr/lib/systemd/system/kube-scheduler.service << EOF
[Unit]
Description=Kubernetes Scheduler
Documentation=https://github.com/kubernetes/kubernetes

[Service]
EnvironmentFile=/opt/kubernetes/cfg/kube-scheduler.conf
ExecStart=/opt/kubernetes/bin/kube-scheduler \$KUBE_SCHEDULER_OPTS
Restart=on-failure

[Install]
WantedBy=multi-user.target
EOF

4）启动并设置开机启动

systemctl daemon-reload
systemctl start kube-scheduler
systemctl enable kube-scheduler
systemctl status kube-scheduler

5）查看集群状态

生成kubectl连接集群的证书：

cat > admin-csr.json <

生成kubeconfig文件：

mkdir /root/.kube

KUBE_CONFIG="/root/.kube/config"
KUBE_APISERVER="https://172.17.87.0:6443"

kubectl config set-cluster kubernetes \
  --certificate-authority=/opt/kubernetes/ssl/ca.pem \
  --embed-certs=true \
  --server=${KUBE_APISERVER} \
  --kubeconfig=${KUBE_CONFIG}
kubectl config set-credentials cluster-admin \
  --client-certificate=./admin.pem \
  --client-key=./admin-key.pem \
  --embed-certs=true \
  --kubeconfig=${KUBE_CONFIG}
kubectl config set-context default \
  --cluster=kubernetes \
  --user=cluster-admin \
  --kubeconfig=${KUBE_CONFIG}
kubectl config use-context default --kubeconfig=${KUBE_CONFIG}

通过kubectl工具查看当前集群组件状态：

kubectl get cs

# 如下输出说明Master节点组件运行正常
Warning: v1 ComponentStatus is deprecated in v1.19+
NAME                 STATUS    MESSAGE             ERROR
scheduler            Healthy   ok                  
controller-manager   Healthy   ok                  
etcd-2               Healthy   {"health":"true"}   
etcd-1               Healthy   {"health":"true"}   
etcd-0               Healthy   {"health":"true"}

6）授权kubelet-bootstrap用户允许请求证书

kubectl create clusterrolebinding kubelet-bootstrap \
--clusterrole=system:node-bootstrapper \
--user=kubelet-bootstrap

五、部署k8s-master1

5.1、创建工作目录并拷贝二进制文件

# 如果新增节点，请创建工作目录（master已创建，新加入节点需要创建）
mkdir -p /opt/kubernetes/{bin,cfg,ssl,logs}

# 从解压的k8s server压缩包中拷贝文件（在 k8s-master1 上执行）
cd /root/TLS/k8s/kubernetes/server/bin
cp kubelet kube-proxy /opt/kubernetes/bin

[root@k8s-master1 bin]# pwd
/opt/kubernetes/bin
[root@k8s-master1 bin]# ll
total 416744
-rwxr-xr-x 1 root root 118128640 Mar 30 08:30 kube-apiserver
-rwxr-xr-x 1 root root 112308224 Mar 30 08:30 kube-controller-manager
-rwxr-xr-x 1 root root 113974120 Mar 30 09:18 kubelet
-rwxr-xr-x 1 root root  39485440 Mar 30 09:18 kube-proxy
-rwxr-xr-x 1 root root  42848256 Mar 30 08:30 kube-scheduler

5.2、部署kubelet

1）创建配置文件

cat > /opt/kubernetes/cfg/kubelet.conf << EOF
KUBELET_OPTS="--logtostderr=false \\
--v=2 \\
--log-dir=/opt/kubernetes/logs \\
--hostname-override=k8s-master1 \\
--network-plugin=cni \\
--kubeconfig=/opt/kubernetes/cfg/kubelet.kubeconfig \\
--bootstrap-kubeconfig=/opt/kubernetes/cfg/bootstrap.kubeconfig \\
--config=/opt/kubernetes/cfg/kubelet-config.yml \\
--cert-dir=/opt/kubernetes/ssl \\
--pod-infra-container-image=lizhenliang/pause-amd64:3.0"
EOF

参数说明：

--hostname-override：显示名称，集群中唯一

--network-plugin：启用CNI

--kubeconfig：空路径，会自动生成，后面用于连接apiserver

--bootstrap-kubeconfig：首次启动向apiserver申请证书

--config：配置参数文件

--cert-dir：kubelet证书生成目录

--pod-infra-container-image：管理Pod网络容器的镜像

2）配置参数文件

cat > /opt/kubernetes/cfg/kubelet-config.yml << EOF
kind: KubeletConfiguration
apiVersion: kubelet.config.k8s.io/v1beta1
address: 0.0.0.0
port: 10250
readOnlyPort: 10255
cgroupDriver: cgroupfs
clusterDNS:
- 10.0.0.2
clusterDomain: cluster.local 
failSwapOn: false
authentication:
  anonymous:
    enabled: false
  webhook:
    cacheTTL: 2m0s
    enabled: true
  x509:
    clientCAFile: /opt/kubernetes/ssl/ca.pem 
authorization:
  mode: Webhook
  webhook:
    cacheAuthorizedTTL: 5m0s
    cacheUnauthorizedTTL: 30s
evictionHard:
  imagefs.available: 15%
  memory.available: 100Mi
  nodefs.available: 10%
  nodefs.inodesFree: 5%
maxOpenFiles: 1000000
maxPods: 110
EOF

3）生成kubelet初次加入集群引导kubeconfig文件

KUBE_CONFIG="/opt/kubernetes/cfg/bootstrap.kubeconfig"
KUBE_APISERVER="https://172.17.87.0:6443" # apiserver IP:PORT
TOKEN="c47ffb939f5ca36231d9e3121a252940" # 与token.csv里保持一致

# 生成 kubelet bootstrap kubeconfig 配置文件
kubectl config set-cluster kubernetes \
  --certificate-authority=/opt/kubernetes/ssl/ca.pem \
  --embed-certs=true \
  --server=${KUBE_APISERVER} \
  --kubeconfig=${KUBE_CONFIG}
kubectl config set-credentials "kubelet-bootstrap" \
  --token=${TOKEN} \
  --kubeconfig=${KUBE_CONFIG}
kubectl config set-context default \
  --cluster=kubernetes \
  --user="kubelet-bootstrap" \
  --kubeconfig=${KUBE_CONFIG}
kubectl config use-context default --kubeconfig=${KUBE_CONFIG}

4）systemd管理kubelet

cat > /usr/lib/systemd/system/kubelet.service << EOF
[Unit]
Description=Kubernetes Kubelet
After=docker.service

[Service]
EnvironmentFile=/opt/kubernetes/cfg/kubelet.conf
ExecStart=/opt/kubernetes/bin/kubelet \$KUBELET_OPTS
Restart=on-failure
LimitNOFILE=65536

[Install]
WantedBy=multi-user.target
EOF

5）启动并设置开机启动

systemctl daemon-reload
systemctl start kubelet
systemctl enable kubelet
systemctl status kubelet

6）批准kubelet证书申请并加入集群

# 查看kubelet证书请求
kubectl get csr
NAME                                                   AGE   SIGNERNAME                                    REQUESTOR           CONDITION
node-csr-jaqXhwxFBnD-1ui9omPdF__0SGovk2ZRhszz_QMGJxI   62s   kubernetes.io/kube-apiserver-client-kubelet   kubelet-bootstrap   Pending

# 批准申请
kubectl certificate approve node-csr-jaqXhwxFBnD-1ui9omPdF__0SGovk2ZRhszz_QMGJxI

# 查看节点（由于网络插件还没有部署，节点会没有准备就绪 NotReady）
kubectl get node
NAME          STATUS     ROLES    AGE   VERSION
k8s-master1   NotReady      7s    v1.20.4

5.3、部署kube-proxy

1）创建配置文件

cat > /opt/kubernetes/cfg/kube-proxy.conf << EOF
KUBE_PROXY_OPTS="--logtostderr=false \\
--v=2 \\
--log-dir=/opt/kubernetes/logs \\
--config=/opt/kubernetes/cfg/kube-proxy-config.yml"
EOF

2）配置参数文件

cat > /opt/kubernetes/cfg/kube-proxy-config.yml << EOF
kind: KubeProxyConfiguration
apiVersion: kubeproxy.config.k8s.io/v1alpha1
bindAddress: 0.0.0.0
metricsBindAddress: 0.0.0.0:10249
clientConnection:
  kubeconfig: /opt/kubernetes/cfg/kube-proxy.kubeconfig
hostnameOverride: k8s-master1
clusterCIDR: 10.0.0.0/24
EOF

3）生成kube-proxy.kubeconfig文件

生成kube-proxy证书：

# 切换工作目录
cd ~/TLS/k8s

# 创建证书请求文件
cat > kube-proxy-csr.json << EOF
{
  "CN": "system:kube-proxy",
  "hosts": [],
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "CN",
      "L": "BeiJing",
      "ST": "BeiJing",
      "O": "k8s",
      "OU": "System"
    }
  ]
}
EOF

# 生成证书
cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=kubernetes kube-proxy-csr.json | cfssljson -bare kube-proxy

生成kubeconfig文件：

KUBE_CONFIG="/opt/kubernetes/cfg/kube-proxy.kubeconfig"
KUBE_APISERVER="https://172.17.87.0:6443"

kubectl config set-cluster kubernetes \
  --certificate-authority=/opt/kubernetes/ssl/ca.pem \
  --embed-certs=true \
  --server=${KUBE_APISERVER} \
  --kubeconfig=${KUBE_CONFIG}
kubectl config set-credentials kube-proxy \
  --client-certificate=./kube-proxy.pem \
  --client-key=./kube-proxy-key.pem \
  --embed-certs=true \
  --kubeconfig=${KUBE_CONFIG}
kubectl config set-context default \
  --cluster=kubernetes \
  --user=kube-proxy \
  --kubeconfig=${KUBE_CONFIG}
kubectl config use-context default --kubeconfig=${KUBE_CONFIG}

4）systemd管理kube-proxy

cat > /usr/lib/systemd/system/kube-proxy.service << EOF
[Unit]
Description=Kubernetes Proxy
After=network.target

[Service]
EnvironmentFile=/opt/kubernetes/cfg/kube-proxy.conf
ExecStart=/opt/kubernetes/bin/kube-proxy \$KUBE_PROXY_OPTS
Restart=on-failure
LimitNOFILE=65536

[Install]
WantedBy=multi-user.target
EOF

5）启动并设置开机启动

systemctl daemon-reload
systemctl start kube-proxy
systemctl enable kube-proxy
systemctl status kube-proxy

5.4、部署网络组件Calico

Calico是一个纯三层的数据中心网络方案，是目前Kubernetes主流的网络方案。

官网：https://docs.projectcalico.org/
下载： https://docs.projectcalico.org/v3.20/manifests/calico.yaml

# 指定目录
mkdir -p /opt/kubernetes/calico
cd /opt/kubernetes/calico

#下载
wget https://docs.projectcalico.org/v3.20/manifests/calico.yaml --no-check-certificate

# 部署Calico
kubectl apply -f calico.yaml
kubectl get pods -n kube-system

NAME                                      READY   STATUS    RESTARTS   AGE
calico-kube-controllers-97769f7c7-q9thh   1/1     Running   0          2m12s
calico-node-pjxtr                         1/1     Running   0          2m12s

# 等Calico Pod都Running，节点也会准备就绪
kubectl get node
NAME          STATUS   ROLES    AGE   VERSION
k8s-master1   Ready       18m   v1.20.4

5.5、授权apiserver访问kubelet

应用场景：例如kubectl logs

cat > apiserver-to-kubelet-rbac.yaml << EOF
apiVersion: rbac.authorization.k8s.io/v1
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
      - pods/log
    verbs:
      - "*"
---
apiVersion: rbac.authorization.k8s.io/v1
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

kubectl apply -f apiserver-to-kubelet-rbac.yaml

5.6、新增Worker Node

1）在 k8s-master1 拷贝已相关文件到新节点 k8s-node1，k8s-node2

# 在 k8s-master1 涉及文件拷贝到新节点 k8s-node1，k8s-node2

scp -r /opt/kubernetes root@k8s-node1:/opt/kubernetes

scp -r /usr/lib/systemd/system/{kubelet,kube-proxy}.service root@k8s-node1:/usr/lib/systemd/system



scp -r /opt/kubernetes root@k8s-node2:/opt/kubernetes

scp -r /usr/lib/systemd/system/{kubelet,kube-proxy}.service root@k8s-node2:/usr/lib/systemd/system

2）删除kubelet证书和kubeconfig文件（在k8s-node1，k8s-node2执行）

注：这几个文件是证书申请审批后自动生成的，每个Node不同，必须删除

rm -f /opt/kubernetes/cfg/kubelet.kubeconfig 
rm -f /opt/kubernetes/ssl/kubelet*

3）修改配置文件中的主机名

vim /opt/kubernetes/cfg/kubelet.conf
--hostname-override=k8s-node1

vim /opt/kubernetes/cfg/kube-proxy-config.yml
hostnameOverride: k8s-node1

4）启动并设置开机启动

systemctl daemon-reload
systemctl start kubelet kube-proxy
systemctl enable kubelet kube-proxy
systemctl status kubelet kube-proxy

5）在 k8s-master1上批准新Node kubelet证书申请

# 查看证书请求
kubectl get csr
NAME                                                   AGE   SIGNERNAME                                    REQUESTOR           CONDITION
node-csr-E0cAzR_Tv7S1l6eThCsx5IeVG20AYSeTLOrgW5mAZFA   70s   kubernetes.io/kube-apiserver-client-kubelet   kubelet-bootstrap   Pending

# 同意授权请求
kubectl certificate approve node-csr-E0cAzR_Tv7S1l6eThCsx5IeVG20AYSeTLOrgW5mAZFA

6）查看Node状态

kubectl get nodes
NAME          STATUS   ROLES    AGE    VERSION
k8s-master1   Ready       31m    v1.20.4
k8s-node01    Ready       111s   v1.20.4

k8s-node2（172.17.86.255 ）节点同上。记得修改主机名！

六、部署Dashboard和CoreDNS

官网：https://v1-20.docs.kubernetes.io/zh/docs/tasks/access-application-cluster/web-ui-dashboard/
下载：https://raw.githubusercontent.com/kubernetes/dashboard/v2.0.0/aio/deploy/recommended.yaml

6.1、部署Dashboard

# 指定目录
mkdir -p /opt/kubernetes/dashboard
cd /opt/kubernetes/dashboard

# 下载
wget https://raw.githubusercontent.com/kubernetes/dashboard/v2.0.0/aio/deploy/recommended.yaml

# 重命名
mv recommended.yaml kubernetes-dashboard.yaml

官方的kubernetes-dashboard.yaml文件中service的type类型为ClusterIP，这种方式要访问dashboard需要通过代理，所以改为spec.type: NodePort; spec.ports.nodePort: 30001方式，这样部署完后，就可以直接通过nodeIP:port的方式访问

• kind: Service
• apiVersion: v1
• metadata:
•   labels:
•     k8s-app: kubernetes-dashboard
•   name: kubernetes-dashboard
•   namespace: kubernetes-dashboard
• spec:
•   type: NodePort
•   ports:
•     - nodePort: 30001
•       port: 443
•       targetPort: 8443
•   selector:
•     k8s-app: kubernetes-dashboard

kubectl apply -f kubernetes-dashboard.yaml

# 查看部署
kubectl get pods,svc -n kubernetes-dashboard

访问地址：https://NodeIP:30001

创建service account并绑定默认cluster-admin管理员集群角色：

kubectl create serviceaccount dashboard-admin -n kube-system
kubectl create clusterrolebinding dashboard-admin --clusterrole=cluster-admin --serviceaccount=kube-system:dashboard-admin

# kubernetes DashBoard token
kubectl describe secrets -n kube-system $(kubectl -n kube-system get secret | awk '/dashboard-admin/{print $1}')

使用输出的token登录Dashboard：

直接输NodeIP: Port 出现Client sent an HTTP request to an HTTPS server. 问题。手输 https://NodeIP: Port 就没问题

6.2、部署CoreDNS

官方 https://kubernetes.io/zh/docs/tasks/administer-cluster/coredns/

有关手动部署或替换 kube-dns，请参阅 CoreDNS GitHub 项目

deployment/kubernetes at master · coredns/deployment · GitHub

复制粘贴里面内容coredns.yaml.sed（在下面vim coredns里粘贴以下内容）

apiVersion: v1
kind: ServiceAccount
metadata:
  name: coredns
  namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  labels:
    kubernetes.io/bootstrapping: rbac-defaults
  name: system:coredns
rules:
  - apiGroups:
    - ""
    resources:
    - endpoints
    - services
    - pods
    - namespaces
    verbs:
    - list
    - watch
  - apiGroups:
    - discovery.k8s.io
    resources:
    - endpointslices
    verbs:
    - list
    - watch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  annotations:
    rbac.authorization.kubernetes.io/autoupdate: "true"
  labels:
    kubernetes.io/bootstrapping: rbac-defaults
  name: system:coredns
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: system:coredns
subjects:
- kind: ServiceAccount
  name: coredns
  namespace: kube-system
---
apiVersion: v1
kind: ConfigMap
metadata:
  name: coredns
  namespace: kube-system
data:
  Corefile: |
    .:53 {
        errors
        health {
          lameduck 5s
        }
        ready
        kubernetes cluster.local  in-addr.arpa ip6.arpa {
          fallthrough in-addr.arpa ip6.arpa
        }
        prometheus :9153
        forward . /etc/resolv.conf {
          max_concurrent 1000
        }
        cache 30
        loop
        reload
        loadbalance
    }
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: coredns
  namespace: kube-system
  labels:
    k8s-app: kube-dns
    kubernetes.io/name: "CoreDNS"
spec:
  # replicas: not specified here:
  # 1. Default is 1.
  # 2. Will be tuned in real time if DNS horizontal auto-scaling is turned on.
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxUnavailable: 1
  selector:
    matchLabels:
      k8s-app: kube-dns
  template:
    metadata:
      labels:
        k8s-app: kube-dns
    spec:
      priorityClassName: system-cluster-critical
      serviceAccountName: coredns
      tolerations:
        - key: "CriticalAddonsOnly"
          operator: "Exists"
      nodeSelector:
        kubernetes.io/os: linux
      affinity:
         podAntiAffinity:
           requiredDuringSchedulingIgnoredDuringExecution:
           - labelSelector:
               matchExpressions:
               - key: k8s-app
                 operator: In
                 values: ["kube-dns"]
             topologyKey: kubernetes.io/hostname
      containers:
      - name: coredns
        image: coredns/coredns:1.9.0
        imagePullPolicy: IfNotPresent
        resources:
          limits:
            memory: 170Mi
          requests:
            cpu: 100m
            memory: 70Mi
        args: [ "-conf", "/etc/coredns/Corefile" ]
        volumeMounts:
        - name: config-volume
          mountPath: /etc/coredns
          readOnly: true
        ports:
        - containerPort: 53
          name: dns
          protocol: UDP
        - containerPort: 53
          name: dns-tcp
          protocol: TCP
        - containerPort: 9153
          name: metrics
          protocol: TCP
        securityContext:
          allowPrivilegeEscalation: false
          capabilities:
            add:
            - NET_BIND_SERVICE
            drop:
            - all
          readOnlyRootFilesystem: true
        livenessProbe:
          httpGet:
            path: /health
            port: 8080
            scheme: HTTP
          initialDelaySeconds: 60
          timeoutSeconds: 5
          successThreshold: 1
          failureThreshold: 5
        readinessProbe:
          httpGet:
            path: /ready
            port: 8181
            scheme: HTTP
      dnsPolicy: Default
      volumes:
        - name: config-volume
          configMap:
            name: coredns
            items:
            - key: Corefile
              path: Corefile
---
apiVersion: v1
kind: Service
metadata:
  name: kube-dns
  namespace: kube-system
  annotations:
    prometheus.io/port: "9153"
    prometheus.io/scrape: "true"
  labels:
    k8s-app: kube-dns
    kubernetes.io/cluster-service: "true"
    kubernetes.io/name: "CoreDNS"
spec:
  selector:
    k8s-app: kube-dns
  clusterIP: 10.0.0.2
  ports:
  - name: dns
    port: 53
    protocol: UDP
  - name: dns-tcp
    port: 53
    protocol: TCP
  - name: metrics
    port: 9153
    protocol: TCP

ConfigMap

     data.Corefile: |

          kubernetes cluster.local in-addr.arpa ip6.arpa
          forward . /etc/resolv.conf
Service

    spec.clusterIP: 10.0.0.2（kubelet配置文件中的clusterDNS）

CoreDNS用于集群内部Service名称解析：

# 指定目录
mkdir -p /opt/kubernetes/coredns
cd  /opt/kubernetes/coredns

vim coredns.yaml #复制上个窗口内容

kubectl apply -f coredns.yaml 
 
kubectl get pods -n kube-system  
NAME                          READY   STATUS    RESTARTS   AGE 
coredns-5ffbfd976d-j6shb      1/1     Running   0          32s

DNS解析测试：

kubectl run -it --rm dns-test --image=busybox:1.28.4 sh

If you don't see a command prompt, try pressing enter.
/ # nslookup kubernetes
Server:    10.0.0.2
Address 1: 10.0.0.2 kube-dns.kube-system.svc.cluster.local

Name:      kubernetes
Address 1: 10.0.0.1 kubernetes.default.svc.cluster.local

解析没问题。

至此一个单Master集群就搭建完成了！这个环境就足以满足学习实验了，如果你的服务器配置较高，可继续扩容多Master集群！

七、扩容多Master（高可用架构）

Kubernetes作为容器集群系统，通过健康检查+重启策略实现了Pod故障自我修复能力，通过调度算法实现将Pod分布式部署，并保持预期副本数，根据Node失效状态自动在其他Node拉起Pod，实现了应用层的高可用性。

针对Kubernetes集群，高可用性还应包含以下两个层面的考虑：Etcd数据库的高可用性和Kubernetes Master组件的高可用性。 而Etcd我们已经采用3个节点组建集群实现高可用，本节将对Master节点高可用进行说明和实施。

Master节点扮演着总控中心的角色，通过不断与工作节点上的Kubelet和kube-proxy进行通信来维护整个集群的健康工作状态。如果Master节点故障，将无法使用kubectl工具或者API做任何集群管理。

Master节点主要有三个服务kube-apiserver、kube-controller-manager和kube-scheduler，其中kube-controller-manager和kube-scheduler组件自身通过选择机制已经实现了高可用，所以Master高可用主要针对kube-apiserver组件，而该组件是以HTTP API提供服务，因此对他高可用与Web服务器类似，增加负载均衡器对其负载均衡即可，并且可水平扩容。

多Master架构图：

7.1、部署 k8s-master2 节点

现在需要再增加一台新服务器，作为 k8s-master2 节点，IP是172.17.87.1。

k8s-master2 与已部署的 k8s-master1 所有操作一致。所以我们只需将 k8s-master1 所有K8s文件拷贝过来，再修改下服务器IP和主机名启动即可

1）安装docker(此前已部署ok，不用执行，后续新增除 k8s-master2、k8s-master3 之外的节点可以使用)

scp /usr/bin/docker* [email protected]:/usr/bin
scp /usr/bin/runc [email protected]:/usr/bin
scp /usr/bin/containerd* [email protected]:/usr/bin
scp /usr/lib/systemd/system/docker.service [email protected]:/usr/lib/systemd/system
scp -r /etc/docker [email protected]:/etc

# 在Master2启动Docker
systemctl daemon-reload
systemctl start docker
systemctl enable docker

2）创建etcd证书目录（此前已部署ok，不用执行，后续新增除 k8s-master2、k8s-master3 之外的节点etcd可以使用)

# 在新增 k8s-master4，k8s-master5 创建etcd 证书目录执行
mkdir -p /opt/etcd/ssl

3）拷贝 k8s-master1 上文件到 k8s-master2

# k8s-master1 上拷贝所有K8s文件和证书到 k8s-master2
scp -r /opt/kubernetes root@k8s-master2:/opt/kubernetes
scp /usr/lib/systemd/system/kube* root@k8s-master2:/usr/lib/systemd/system
scp /usr/bin/kubectl  root@k8s-master2:/usr/bin
scp -r ~/.kube root@k8s-master2:~/.kube

4）删除证书文件(k8s-master2)

# 删除kubelet证书和kubeconfig文件
rm -f /opt/kubernetes/cfg/kubelet.kubeconfig 
rm -f /opt/kubernetes/ssl/kubelet*

5）修改配置文件IP和主机名(k8s-master)

# 修改apiserver、kubelet和kube-proxy配置文件为本地IP
vim /opt/kubernetes/cfg/kube-apiserver.conf 
...
--bind-address=172.17.87.1 \
--advertise-address=172.17.87.1 \
...

vim /opt/kubernetes/cfg/kubelet.conf
--hostname-override=k8s-master02

vim /opt/kubernetes/cfg/kube-proxy-config.yml
hostnameOverride: k8s-master02

6）启动并设置开机启动

systemctl daemon-reload
systemctl start kube-apiserver kube-controller-manager kube-scheduler kubelet kube-proxy
systemctl enable kube-apiserver kube-controller-manager kube-scheduler kubelet kube-proxy

7）查看集群状态

# 修改连接master为本机IP
vim ~/.kube/config
...
server: https://172.17.87.1:6443

kubectl get cs
Warning: v1 ComponentStatus is deprecated in v1.19+
NAME                 STATUS    MESSAGE             ERROR
scheduler            Healthy   ok                  
controller-manager   Healthy   ok                  
etcd-2               Healthy   {"health":"true"}   
etcd-1               Healthy   {"health":"true"}   
etcd-0               Healthy   {"health":"true"}

8）批准kubelet证书申请

# 查看证书请求
kubectl get csr
NAME                      AGE          SIGNERNAME          REQUESTOR           CONDITION
node-csr-JYNknakEa_YpHz797oKaN-ZTk43nD51Zc9CJkBLcASU   85m   kubernetes.io/kube-apiserver-client-kubelet   kubelet-bootstrap   Pending
# 授权请求
kubectl certificate approve node-csr-JYNknakEa_YpHz797oKaN-ZTk43nD51Zc9CJkBLcASU

# 查看Node
kubectl get node
NAME        STATUS   ROLES    AGE   VERSION
k8s-master1    Ready       34h   v1.20.4
k8s-master2    Ready       2m   v1.20.4
k8s-node1     Ready       33h   v1.20.4
k8s-node2     Ready       33h   v1.20.4

9）k8s  node ROLES显示

kubectl label node k8s-master2  node-role.kubernetes.io/master=

kubectl label node k8s-node1 k8s-node2  node-role.kubernetes.io/worker=worker


[root@k8s-master1 ]# kubectl get node
NAME          STATUS   ROLES    AGE     VERSION
k8s-master1   Ready    master   8h      v1.20.0
k8s-master2   Ready    master   89m     v1.20.0
k8s-node1     Ready    worker   7h43m   v1.20.0
k8s-node2     Ready    worker   7h26m   v1.20.0

7.2、部署Nginx+Keepalived高可用负载均衡器

kube-apiserver高可用架构图：

Nginx是一个主流Web服务和反向代理服务器，这里用四层实现对apiserver实现负载均衡。

Keepalived是一个主流高可用软件，基于VIP绑定实现服务器双机热备，在上述拓扑中，Keepalived主要根据Nginx运行状态判断是否需要故障转移（漂移VIP），例如当Nginx主节点挂掉，VIP会自动绑定在Nginx备节点，从而保证VIP一直可用，实现Nginx高可用。

注1：为了节省机器，这里与K8s Master节点机器复用。也可以独立于k8s集群之外部署，只要nginx与apiserver能通信就行。

注2：如果你是在公有云上，一般都不支持keepalived，那么你可以直接用它们的负载均衡器产品，直接负载均衡多台Master kube-apiserver，架构与上面一样。

在两台Master(k8s-master1, k8s-master2)节点操作：

1）安装软件包（主/备）

yum install epel-release -y
yum install nginx keepalived -y

2）Nginx配置文件（主备一样，k8s-master1，k8s-master2执行）

cat > /etc/nginx/nginx.conf << "EOF"
worker_processes  1;

events {
    worker_connections  1024;
}

http {
    include       mime.types;
    default_type  application/octet-stream;

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  /var/log/nginx/k8s-access.log  main;

    sendfile        on;

    keepalive_timeout  65;
   
    upstream k8s-apiserver {

       server 172.17.87.0:6443;   # Master1 APISERVER IP:PORT
       server 172.17.87.1:6443;   # Master2 APISERVER IP:PORT

    }

    server {
        listen       16443;
        server_name  localhost;

        location / {
           proxy_pass https://k8s-apiserver;
        }


        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
            root   html;
        }
    }
}
EOF

3）keepalived配置文件（Nginx Master，在k8s-master1执行）

cat > /etc/keepalived/keepalived.conf << EOF
global_defs { 
   notification_email { 
     [email protected] 
     [email protected] 
     [email protected] 
   } 
   notification_email_from [email protected]  
   smtp_server 127.0.0.1 
   smtp_connect_timeout 30 
   router_id NGINX_MASTER
} 

vrrp_script check_nginx {
    script "/etc/keepalived/check_nginx.sh"
}

vrrp_instance VI_1 { 
    state MASTER 
    interface eth0 # 修改为实际网卡名
    virtual_router_id 51 # VRRP 路由 ID实例，每个实例是唯一的 
    priority 100    # 优先级，备服务器设置 90 
    advert_int 1    # 指定VRRP 心跳包通告间隔时间，默认1秒 
    authentication { 
        auth_type PASS      
        auth_pass 1111 
    }  
    # 虚拟IP
    virtual_ipaddress { 
        10.0.0.88/24
    } 
    track_script {
        check_nginx
    } 
}
EOF

参数说明：

vrrp_script：指定检查nginx工作状态脚本（根据nginx状态判断是否故障转移）

virtual_ipaddress：虚拟IP（VIP）

准备上述配置文件中检查nginx运行状态的脚本：

cat > /etc/keepalived/check_nginx.sh  << "EOF"
#!/bin/bash
count=$(ss -antp |grep 16443 |egrep -cv "grep|$$")

if [ "$count" -eq 0 ];then
    exit 1
else
    exit 0
fi
EOF
chmod +x /etc/keepalived/check_nginx.sh

注：keepalived根据脚本返回状态码（0为工作正常，非0不正常）判断是否故障转移

4）keepalived配置文件（Nginx Backup，在k8s-master2执行）

cat > /etc/keepalived/keepalived.conf << EOF
global_defs { 
   notification_email { 
     [email protected] 
     [email protected] 
     [email protected] 
   } 
   notification_email_from [email protected]  
   smtp_server 127.0.0.1 
   smtp_connect_timeout 30 
   router_id NGINX_BACKUP
} 

vrrp_script check_nginx {
    script "/etc/keepalived/check_nginx.sh"
}

vrrp_instance VI_1 { 
    state BACKUP 
    interface eth0
    virtual_router_id 51 # VRRP 路由 ID实例，每个实例是唯一的 
    priority 90
    advert_int 1
    authentication { 
        auth_type PASS      
        auth_pass 1111 
    }  
    virtual_ipaddress { 
        10.0.0.88/24
    } 
    track_script {
        check_nginx
    } 
}
EOF

准备上述配置文件中检查nginx运行状态的脚本：

cat > /etc/keepalived/check_nginx.sh  << "EOF"
#!/bin/bash
count=$(ss -antp |grep 16443 |egrep -cv "grep|$$")

if [ "$count" -eq 0 ];then
    exit 1
else
    exit 0
fi
EOF
chmod +x /etc/keepalived/check_nginx.sh

5）启动并设置开机启动

systemctl daemon-reload
systemctl start nginx keepalived
systemctl enable nginx keepalived

6）查看keepalived工作状态

可以看到，在eth0网卡绑定了10.0.0.88 虚拟IP，说明工作正常。

7）Nginx+Keepalived高可用测试

关闭主节点Nginx，测试VIP是否漂移到备节点服务器。

在Nginx Master(k8s-master1)执行systemctl stop nginx;

在Nginx Backup(k8s-master2)，ip addr命令查看已成功绑定VIP。

8）访问负载均衡器测试

找K8s集群中任意一个节点，使用curl查看K8s版本测试，使用VIP访问:

curl -k https://10.0.0.88:16443/version
{
  "major": "1",
  "minor": "20",
  "gitVersion": "v1.20.4",
  "gitCommit": "e87da0bd6e03ec3fea7933c4b5263d151aafd07c",
  "gitTreeState": "clean",
  "buildDate": "2021-02-18T16:03:00Z",
  "goVersion": "go1.15.8",
  "compiler": "gc",
  "platform": "linux/amd64"
}

可以正确获取到K8s版本信息，说明负载均衡器搭建正常。该请求数据流程：curl -> vip(nginx) -> apiserver

通过查看Nginx日志也可以看到转发apiserver IP：/var/log/nginx/k8s-access.log

9）修改所有Worker Node连接LB VIP

接下来就是要改所有Worker Node（kubectl get node命令查看到的节点）组件配置文件，由原来172.17.87.0修改为10.0.0.88（VIP）。

在所有Worker Node(k8s-node1, k8s-node2 ..)执行：

sed -i 's#172.17.87.0:6443#10.0.0.88:16443#' /opt/kubernetes/cfg/*
systemctl restart kubelet kube-proxy

检查节点状态：

kubectl get node 
NAME           STATUS   ROLES    AGE     VERSION
k8s-master02   Ready       26m     v1.20.4
k8s-master1    Ready       3h21m   v1.20.4
k8s-node01     Ready       172m    v1.20.4
k8s-node02     Ready       167m    v1.20.4

至此，一套完整的 Kubernetes 高可用集群就部署完成了！