概述

Kubernetes，又称为 k8s（首字母为 k、首字母与尾字母之间有 8 个字符、尾字母为 s，所以简称 k8s）或者简称为 “kube” ，是一种可自动实施 Linux 容器操作的开源平台。它可以帮助用户省去应用容器化过程的许多手动部署和扩展操作。也就是说，您可以将运行 Linux 容器的多组主机聚集在一起，由 Kubernetes 帮助您轻松高效地管理这些集群。而且，这些集群可跨公共云、私有云或混合云部署主机。

一、环境准备

1.1 部署k8s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) 方式二：二进制包 从Github下载kubernetes发行二进制包，手动部署每个组件，组成kubernetes集群。

注意：服务器最低要求2核CPU与2G内存，磁盘空间20G以上。

1.2 软件版本
软件版本
LinuxCentos 7.9_x64
DockerDocker CE 19.03
KubernetesKubernetes v1.20
1.3 服务器整体规划
角色IP组件
k8s-master-01192.168.20.21kube-apiserver, kube-controller-manager, kube-scheduler, etcd
k8s-master-02192.168.20.22kube-apiserver, kube-controller-manager, kube-scheduler, etcd
k8s-master-03192.168.20.23Nginx, keepalived
k8s-worker-01192.168.20.24kubelet, kube-proxy, docker, etcd
k8s-worker-02192.168.20.25kubelet, kube-proxy, docker, etcd
k8s-worker-03192.168.20.26Nginx, keepalived
Vip192.168.20.27/

这套集群我分三部分实施

  • 一是先部署一套单Master架构(3台)
  • 二是扩容为双或多Master架构(4台或者6台)
  • 三是配置前端Web负载均衡

单Master架构图 单Master架构图

单Master集群规划

角色IP组件
k8s-master-01192.168.20.21kube-apiserver kube-controller-manager kube-scheduler etcd
k8s-worker-01192.168.20.24kubelet kube-proxy docker etcd
k8s-worker-02192.168.20.25kubelet kube-proxy docker etcd
1.4 操作系统初始化
systemctl stop firewalld \
&& systemctl disable firewalld \
&& sed -i 's/enforcing/disabled/' /etc/selinux/config \
&& sed -ri 's/.*swap.*/#&/' /etc/fstab \
&& echo "net.bridge.bridge-nf-call-ip6tables = 1" >> /etc/sysctl.d/k8s.conf \
&& echo "net.bridge.bridge-nf-call-iptables = 1" >> /etc/sysctl.d/k8s.conf \
&& sysctl --system \
&& yum install ntpdate -y \
&& timedatectl set-timezone Asia/Shanghai \
&& ntpdate ntp.aliyun.com \
&& date


cat >> /etc/hosts << EOF
192.168.20.21  k8s-master-01   #后续扩容的IP也可以添加进来
192.168.20.24  k8s-worker-01
192.168.20.25  k8s-worker-02
EOF

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-1192.168.20.21
etcd-2192.168.20.24
etcd-3192.168.20.25

⚠️ 注意 这里为了节省资源与k8s节点机器复用，etcd也可以在k8s集群之外部署，只要kube-apiserver能正常连接到就行

2.1 整备cfssl证书生成工具

CFSSL是CloudFlare开源的一款PKI/TLS工具。 CFSSL 包含一个命令行工具 和一个用于 签名，验证并且捆绑TLS证书的 HTTP API 服务。 使用Go语言编写。

[k8s-master-01]# wget https://pkg.cfssl.org/R1.2/cfssl_linux-amd64
[k8s-master-01]# wget https://pkg.cfssl.org/R1.2/cfssljson_linux-amd64
[k8s-master-01]# wget https://pkg.cfssl.org/R1.2/cfssl-certinfo_linux-amd64
[k8s-master-01]# chmod +x cfssl_linux-amd64 cfssljson_linux-amd64 cfssl-certinfo_linux-amd64
[k8s-master-01]# mv cfssl_linux-amd64 /usr/local/bin/cfssl
[k8s-master-01]# mv cfssljson_linux-amd64 /usr/local/bin/cfssljson
[k8s-master-01]# mv cfssl-certinfo_linux-amd64 /usr/bin/cfssl-certinfo
2.2 生成Etcd CA证书

创建工作目录 [k8s-master-01]# mkdir -pv ~/TLS/{etcd,k8s} && cd ~/TLS/etcd 自签CA

[k8s-master-01]# cat > ca-config.json << EOF
{
  "signing": {
    "default": {
      "expiry": "87600h"
    },
    "profiles": {
      "www": {
         "expiry": "87600h",
         "usages": [
            "signing",
            "key encipherment",
            "server auth",
            "client auth"
        ]
      }
    }
  }
}
EOF


[k8s-master-01]# cat > ca-csr.json << EOF
{
    "CN": "etcd CA",
    "key": {
        "algo": "rsa",
        "size": 2048
    },
    "names": [
        {
            "C": "CN",
            "L": "Beijing",
            "ST": "Beijing"
        }
    ]
}
EOF

生成证书

[k8s-master-01]# cfssl gencert -initca ca-csr.json | cfssljson -bare ca -
[k8s-master-01]# ls *pem
ca-key.pem  ca.pem
2.3 使用自签CA签发Etcd https证书
[k8s-master-01]# cat > server-csr.json << EOF
{
    "CN": "etcd",
    "hosts": [
    "192.168.20.21",
    "192.168.20.24",
    "192.168.20.25"
    ],
    "key": {
        "algo": "rsa",
        "size": 2048
    },
    "names": [
        {
            "C": "CN",
            "L": "BeiJing",
            "ST": "BeiJing"
        }
    ]
}
EOF

⚠️ 注意 上述IP为Etcd集群内部通信IP，一个不能少，也不能错！为了方便后期扩容可以多写几个预留的IP。

生成证书

[k8s-master-01]# cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=www server-csr.json | cfssljson -bare server
[k8s-master-01]# ls server*pem
server-key.pem  server.pem
2.4 配置Etcd集群

下载Etcd二进制文件 地址https://github.com/etcd-io/etcd/releases/download/v3.5.4/etcd-v3.5.4-linux-amd64.tar.gz

创建工作目录并解压二进制包

[k8s-master-01]# mkdir -pv /opt/etcd/{bin,cfg,ssl}
[k8s-master-01]# tar -xvf etcd-v3.5.4-linux-amd64.tar.gz
[k8s-master-01]# mv etcd-v3.5.4-linux-amd64/{etcd,etcdctl} /opt/etcd/bin/

创建Etcd配置文件

[k8s-master-01]# 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://192.168.20.21:2380"
ETCD_LISTEN_CLIENT_URLS="https://192.168.20.21:2379"


#[Clustering]
ETCD_INITIAL_ADVERTISE_PEER_URLS="https://192.168.20.21:2380"
ETCD_ADVERTISE_CLIENT_URLS="https://192.168.20.21:2379"
ETCD_INITIAL_CLUSTER="etcd-1=https://192.168.20.21:2380,etcd-2=https://192.168.20.24:2380,etcd-3=https://192.168.20.25:2380"
ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
ETCD_INITIAL_CLUSTER_STATE="new"
EOF

配置文件参数说明

  • 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

添加systemd管理etcd

[k8s-master-01]# 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

将Etcd生成的CA证书拷贝到指定位置

[k8s-master-01]# cp ~/TLS/etcd/ca*pem ~/TLS/etcd/server*pem /opt/etcd/ssl/

启动并设置开机自启

[k8s-master-01]# systemctl daemon-reload
[k8s-master-01]# systemctl start etcd
[k8s-master-01]# systemctl enable etcd

⚠️ 注意 此时Etcd服务是不能正常启动的，需要另外两台Etcd服务同时启动才行

将Master节点生成的Etcd文件拷贝到另外两台机器上

[k8s-master-01]# scp -r /opt/etcd/ root@192.168.20.24:/opt/
[k8s-master-01]# scp -r /opt/etcd/ root@192.168.20.25:/opt/
[k8s-master-01]# scp /usr/lib/systemd/system/etcd.service root@192.168.20.24:/usr/lib/systemd/system/
[k8s-master-01]# scp /usr/lib/systemd/system/etcd.service root@192.168.20.24:/usr/lib/systemd/system/

分别修改节点2与节点3etcd.conf文件配置

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://192.168.20.21:2380"   # 修改此处为当前服务器IP
ETCD_LISTEN_CLIENT_URLS="https://192.168.20.21:2379" # 修改此处为当前服务器IP


#[Clustering]
ETCD_INITIAL_ADVERTISE_PEER_URLS="https://192.168.20.21:2380" # 修改此处为当前服务器IP
ETCD_ADVERTISE_CLIENT_URLS="https://192.168.20.21:2379" # 修改此处为当前服务器IP
ETCD_INITIAL_CLUSTER="etcd-1=https://192.168.20.21:2380,etcd-2=https://192.168.20.24:2380,etcd-3=https://192.168.20.25:2380"
ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
ETCD_INITIAL_CLUSTER_STATE="new"

重复上面启动并设置开机自启操作

查看集群状态(在任何Etcd节点下操作亦可) 执行以下操作

ETCD_API=3 /opt/etcd/bin/etcdctl \
--write-out=table \
--cacert=/opt/etcd/ssl/ca.pem \
--cert=/opt/etcd/ssl/server.pem \
--key=/opt/etcd/ssl/server-key.pem \
--endpoints=https://192.168.20.21:2379,https://192.168.20.24:2379,https://192.168.20.25:2379 endpoint health

输出

+----------------------------+--------+-------------+-------+
|          ENDPOINT          | HEALTH |    TOOK     | ERROR |
+----------------------------+--------+-------------+-------+
| https://192.168.20.25:2379 |   true | 18.033533ms |       |
| https://192.168.20.24:2379 |   true | 18.334299ms |       |
| https://192.168.20.21:2379 |   true | 19.755788ms |       |
+----------------------------+--------+-------------+-------+

三、安装Docker

⚠️ 注意 这里使用Docker作为容器引擎，也可以更换别的，比如CRI-O和Containerd，因为Kubernetes在v1.24版本正式移除 Dockershim相关代码。

在所有Worker节点安装，安装方式随便，用yum或者二进制都行，这里使用二进制安装 下载地址https://download.docker.com/linux/static/stable/x86_64/docker-19.03.9.tgz

3.1 解压二进制包
[k8s-worker-01]# tar -xvf docker-19.03.9.tgz
[k8s-worker-01]# mv docker/* /usr/local/bin/
[k8s-worker-01]# docker version
3.2 配置docker镜像加速器
[k8s-worker-01]# mkdir /etc/docker
[k8s-worker-01]#cat > /etc/docker/daemon.json << EOF
{
  "registry-mirrors": ["https://b9pmyelo.mirror.aliyuncs.com"]
}
EOF
3.3 添加systemd管理docker
[k8s-worker-01]# 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
3.4 启动并设置开机自启
[k8s-worker-01]# systemctl daemon-reload
[k8s-worker-01]# systemctl daemon-reload
[k8s-worker-01]# systemctl daemon-reload

四、部署Master Node

4.1 部署kube-apiserver

(1).自签证书签发机构(CA)

[k8s-master-01]# cd ~/TLS/k8s
[k8s-master-01]# cat > ca-config.json << EOF
{
  "signing": {
    "default": {
      "expiry": "87600h"
    },
    "profiles": {
      "kubernetes": {
         "expiry": "87600h",
         "usages": [
            "signing",
            "key encipherment",
            "server auth",
            "client auth"
        ]
      }
    }
  }
}
EOF


[k8s-master-01]# 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

[k8s-master-01]# cfssl gencert -initca ca-csr.json | cfssljson -bare ca -
[k8s-master-01]# ls *pem
[k8s-master-01]# ca-key.pem  ca.pem

(2).使用自签CA签发kube-apiserver HTTPS证书

[k8s-master-01]# cat > server-csr.json << EOF
{
    "CN": "kubernetes",
    "hosts": [
      "10.0.0.1",
      "127.0.0.1",
      "192.168.20.21",
      "192.168.20.22",
      "192.168.20.23",
      "192.168.20.24",
      "192.168.20.25",
      "192.168.20.26",
      "192.168.20.27",
      "192.168.20.28",
      "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为所有Master/LB/VIP IP，一个都不能少，一个不能错，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

[k8s-master-01]# cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=kubernetes server-csr.json | cfssljson -bare server
[k8s-master-01]# ls server*pem
server-key.pem  server.pem
4.2 安装kube-apiserver

下载Kubernetes二进制包 下载地址https://dl.k8s.io/v1.20.1/kubernetes-server-linux-amd64.tar.gz

根据不同CPU架构下载对应的二进制包，打开链接会看到** Source Code**、** Client binaries**、** Server binaries**、** Node binaries**四个下载包，但只下载一个Server包就够了，里面已经包含Master和Worker Node二进制文件。 (1).创建目录并解压二进制包

[k8s-master-01]# mkdir -pv /opt/kubernetes/{bin,cfg,ssl,logs}
[k8s-master-01]# tar -xvf kubernetes-server-linux-amd64.tar.gz
[k8s-master-01]# cd kubernetes/server/bin
[k8s-master-01]# cp kube-apiserver kube-scheduler kube-controller-manager /opt/kubernetes/bin
[k8s-master-01]# cp kubectl /usr/local/bin/

(2).创建kube-apiserver配置文件

[k8s-master-01]# cat > /opt/kubernetes/cfg/kube-apiserver.conf << EOF
KUBE_APISERVER_OPTS="--logtostderr=false \\
--v=2 \\
--log-dir=/opt/kubernetes/logs \\
--etcd-servers=https://192.168.20.21:2379,https://192.168.20.224:2379,https://192.168.20.25:2379 \\
--bind-address=192.168.20.21 \\
--secure-port=6443 \\
--advertise-address=192.168.20.21 \\
--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

⚠️ 注意 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

配置文件参数说明

  • —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kube-apiserver生成的证书文件拷贝到kubernetes工作目录
[k8s-master-01]# 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。 (5).创建token文件

# 生成token
[k8s-master-01]# head -c 16 /dev/urandom | od -An -t x | tr -d ' '
dbd2c718063399d5e20f7df6a8f56ca5


# 格式：token，用户名，UID，用户组
[k8s-master-01]# cat > /opt/kubernetes/cfg/token.csv << EOF
dbd2c718063399d5e20f7df6a8f56ca5,kubelet-bootstrap,10001,"system:node-bootstrapper"
EOF

(6).systemd管理kube-apiserver

[k8s-master-01]# 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

[k8s-master-01]# systemctl daemon-reload
[k8s-master-01]# systemctl start kube-apiserver
[k8s-master-01]# systemctl enable kube-apiserver
4.2 部署kube-controller-manager

(1).创建配置文件

[k8s-master-01]# 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）
  • —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kube-controller-manager证书

# 切换工作目录
[k8s-master-01]# cd ~/TLS/k8s


# 创建证书请求文件
[k8s-master-01]# 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
[k8s-master-01]# 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

(3).生成kubeconfig文件（以下是shell命令，直接在终端执行）

# Master 节点执行


KUBE_CONFIG="/opt/kubernetes/cfg/kube-controller-manager.kubeconfig"
KUBE_APISERVER="https://192.168.20.21:6443"


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}

(4).systemd管理controller-manager

[k8s-master-01]# 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

(5).启动并设置开机启动

[k8s-master-01]# systemctl daemon-reload
[k8s-master-01]# systemctl start kube-controller-manager
[k8s-master-01]# systemctl enable kube-controller-manager
4.3 部署kube-scheduler

(1).添加配置文件

[k8s-master-01]# 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kube-scheduler证书

# 切换工作目录
[k8s-master-01]# cd ~/TLS/k8s


# 创建证书请求文件
[k8s-master-01]# 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
[k8s-master-01]# cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=kubernetes kube-scheduler-csr.json | cfssljson -bare kube-scheduler

(3).生成kubeconfig文件（以下是shell命令，直接在终端执行）

# Master 节点执行


KUBE_CONFIG="/opt/kubernetes/cfg/kube-scheduler.kubeconfig"
KUBE_APISERVER="https://192.168.20.21:6443"


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}

(4).systemd管理scheduler

[k8s-master-01]# 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

(5).启动并设置开机启动

[k8s-master-01]# systemctl daemon-reload
[k8s-master-01]# systemctl start kube-scheduler
[k8s-master-01]# systemctl enable kube-scheduler
4.4 查看集群状态

(1).生成kubectl连接集群的证书

[k8s-master-01]# cat > admin-csr.json <<EOF
{
  "CN": "admin",
  "hosts": [],
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "CN",
      "L": "BeiJing",
      "ST": "BeiJing",
      "O": "system:masters",
      "OU": "System"
    }
  ]
}
EOF


# 生成证书
[k8s-master-01]# cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=kubernetes admin-csr.json | cfssljson -bare admin

(2).生成kubeconfig文件

mkdir -pv /root/.kube


KUBE_CONFIG="/root/.kube/config"
KUBE_APISERVER="https://192.168.20.21:6443"


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}

(3).通过kubectl工具查看当前集群组件状态

[k8s-master-01]# kubectl get cs
Warning: v1 ComponentStatus is deprecated in v1.19+
NAME                 STATUS    MESSAGE             ERROR
scheduler            Healthy   ok
controller-manager   Healthy   ok
etcd-0               Healthy   {"health":"true"}
etcd-2               Healthy   {"health":"true"}
etcd-1               Healthy   {"health":"true"}

(3).授权kubelet-bootstrap用户允许请求证书

# Master 节点执行


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

五、部署Worker Node

5.1 创建Worker运行环境
[k8s-worker-01]# mkdir -pv /opt/kubernetes/{bin,cfg,ssl,logs}


# 将Master节点解压的kubernetes-server-linux-amd64目录或者指定文件拷贝到其他节点
[k8s-worker-01]# cp kubernetes-server-linux-amd64/server/bin/{kubelet,kube-proxy} /opt/kubernetes/bin


# 把Master节点生成的ca.pem文件拷贝到当前Worker节点指定目录
[k8s-master-01]# scp ~/TLS/k8s/ca.pem root@192.168.20.24:/opt/kubernetes/ssl/
5.2 部署kubelet

(1).创建配置文件

[k8s-worker-01]# cat > /opt/kubernetes/cfg/kubelet.conf << EOF
KUBELET_OPTS="--logtostderr=false \\
--v=2 \\
--log-dir=/opt/kubernetes/logs \\
--hostname-override=k8s-worker-01 \\
--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

⚠️ 注意 要把—hostname-override=k8s-worker-01 参数后的值改为当前主机名

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

[k8s-worker-01]# 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://192.168.20.21:6443" # kube-apiserver IP:PORT
TOKEN="dbd2c718063399d5e20f7df6a8f56ca5" # 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

[k8s-worker-01]# 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

[k8s-worker-01]# systemctl daemon-reload
[k8s-worker-01]# systemctl start kubelet
[k8s-worker-01]# systemctl enable kubelet

(6).批准kubelet证书申请并加入集群

# 查看kubelet证书请求
[k8s-master-01]# kubectl get csr
NAME                                                   AGE   SIGNERNAME                                    REQUESTOR           CONDITION
node-csr-kIJfIKIKfKG-KK3D4DKkd__nidkeFDI34dFD_dDGde2   57s   kubernetes.io/kube-apiserver-client-kubelet   kubelet-bootstrap   Pending


# 批准申请
[k8s-master-01]# kubectl certificate approve node-csr-kIJfIKIKfKG-KK3D4DKkd__nidkeFDI34dFD_dDGde2


# 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）
[k8s-master-01]# kubectl get node
NAME          STATUS     ROLES    AGE     VERSION
k8s-worker-01 NotReady   <none>   5s      v1.20.15
5.3 部署kube-proxy

(1).创建配置文件

[k8s-worker-01]# 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

[k8s-worker-01]# 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-worker-01
clusterCIDR: 10.0.0.0/24
EOF

⚠️ 注意 要把hostnameOverride: k8s-worker-01 参数后的值改为当前主机名

(3).生成kube-proxy.kubeconfig文件

# 切换工作目录,生成kube-proxy证书.
[k8s-master-01]# cd ~/TLS/k8s


# 创建证书请求文件
[k8s-master-01]# 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
[k8s-master-01]# cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=kubernetes kube-proxy-csr.json | cfssljson -bare kube-proxy
# 查看生成的证书文件
[k8s-master-01]# ls kube-proxy*.pem
kube-proxy-key.pem  kube-proxy.pem

(4).生成kubeconfig文件

# 切换到k8s-worker-01 节点执行


KUBE_CONFIG="/opt/kubernetes/cfg/kube-proxy.kubeconfig"
KUBE_APISERVER="https://192.168.20.21:6443"


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}

(5).systemd管理kube-proxy

[k8s-worker-01]# 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

(6).启动并设置开机启动

[k8s-worker-01]# systemctl daemon-reload
[k8s-worker-01]# systemctl start kube-proxy
[k8s-worker-01]# systemctl enable kube-proxy
5.4 新增Worker Node

(1).拷贝已部署好的Node相关文件到新节点

# 把k8s-Worker-01节点涉及文件拷贝到新增Worker节点上
[k8s-worker-01]# scp -r /opt/kubernetes root@192.168.20.25:/opt/
[k8s-worker-01]# scp -r /usr/lib/systemd/system/{kubelet,kube-proxy}.service root@192.168.20.25:/usr/lib/systemd/system

(2).删除kubelet证书和kubeconfig文件

[k8s-worker-02]# rm -f /opt/kubernetes/cfg/kubelet.kubeconfig
[k8s-worker-02]# rm -f /opt/kubernetes/ssl/kubelet*

⚠️ 注意 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

(3).修改配置文件中的主机名

[k8s-worker-02]# vim /opt/kubernetes/cfg/kubelet.conf
--hostname-override=k8s-worker-02
[k8s-worker-02]# vim /opt/kubernetes/cfg/kube-proxy-config.yml
hostnameOverride: k8s-worker-02

(4) 启动并设置开机启动

[k8s-worker-02]# systemctl daemon-reload
[k8s-worker-02]# systemctl start kubelet kube-proxy
[k8s-worker-02]# systemctl enable kubelet kube-proxy

(5).在Master上批准新Node kubelet证书申请

# 查看证书请求
[k8s-master-01]# kubectl get csr
NAME                                                   AGE   SIGNERNAME                                    REQUESTOR           CONDITION
node-csr-5kdKRFKjurf-dfskk2dgn__krfKGFDkhhkGF_GNFDfd   67s   kubernetes.io/kube-apiserver-client-kubelet   kubelet-bootstrap   Pending


# 同意授权请求
kubectl certificate approve node-csr-5kdKRFKjurf-dfskk2dgn__krfKGFDkhhkGF_GNFDfd

(6).查看Node状态

[k8s-master-01]# kubectl get nodes
NAME          STATUS   ROLES    AGE    VERSION
k8s-worker-01 Ready    <none>   50m    v1.20.15
k8s-worker-02 Ready    <none>   12s    v1.20.15

STATUS显示Ready是已经部署Calico成功运行后的结果

六、 网络与授权

6.1 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 下载地址https://projectcalico.docs.tigera.io/manifests/calico.yaml

# 部署Calico(切换Master节点执行)
# 检查apiserver版本是否与calico.yaml文件里配置是否一致
[k8s-master-01]# kubectl api-versions | grep polic
policy/v1beta1


[k8s-master-01]# kubectl apply -f calico.yaml
[k8s-master-01]# get pods -n kube-system


NAME                                      READY   STATUS    RESTARTS   AGE
calico-kube-controllers-97769f7c7-q9thh   1/1     Running   0          5m25s
calico-node-pjxtr                         1/1     Running   0          5m25s


# 等Calico Pod都Running，节点也会准备就绪
[k8s-master-01]# kubectl get node
NAME          STATUS     ROLES    AGE     VERSION
k8s-worker-01 Ready      <none>   5s      v1.20.15
6.2 授权apiserver访问kubelet

应用场景：例如kubectl logs

[k8s-master-01]# 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

七、部署Dashboard和CoreDNS

7.1 部署Dashboard

Dashboard 是基于网页的 Kubernetes 用户界面 yaml文件下载地址https://raw.githubusercontent.com/kubernetes/dashboard/v2.5.0/aio/deploy/recommended.yaml

# 执行安装Dashboard
[k8s-master-01]# kubectl apply -f recommended.yaml


# 查看Pod名称
[k8s-master-01]# kubectl get pods --namespace=kubernetes-dashboard -o wide
NAME                                         READY   STATUS    RESTARTS   AGE   IP               NODE          NOMINATED NODE   READINESS GATES
dashboard-metrics-scraper-5b8896d7fc-4wsfd   1/1     Running   0          51s   172.16.101.197   k8s-work-01   <none>           <none>
kubernetes-dashboard-cb988587b-mfqjh         1/1     Running   0          51s   172.16.101.196   k8s-work-01   <none>           <none>

修改Dashboard访问类型，默认是通过API Server访问，且URL字符串太长比较麻烦，所以改成NodePort访问(IP:Port)

[k8s-master-01]# kubectl --namespace=kubernetes-dashboard get service kubernetes-dashboard     # 查看当前访问类型
NAME                   TYPE       CLUSTER-IP   EXTERNAL-IP   PORT(S)         AGE
kubernetes-dashboard   ClusterIP  10.0.0.96    <none>        443/TCP         15m

执行编辑操作

[k8s-master-01]# kubectl --namespace=kubernetes-dashboard edit service kubernetes-dashboard


spec:
  clusterIP: 10.0.0.96
  clusterIPs:
  - 10.0.0.96
  externalTrafficPolicy: Cluster
  ports:
  - nodePort: 31730
    port: 443
    protocol: TCP
    targetPort: 8443
  selector:
    k8s-app: kubernetes-dashboard
  sessionAffinity: None
  type: NodePort   # 这个字段修改NodePort
status:
  loadBalancer: {}

重新查看访问类型

[k8s-master-01]# kubectl --namespace=kubernetes-dashboard get service kubernetes-dashboard
NAME                   TYPE       CLUSTER-IP   EXTERNAL-IP   PORT(S)         AGE
kubernetes-dashboard   NodePort   10.0.0.96    <none>        443:31730/TCP   17m

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

[k8s-master-01]# kubectl create serviceaccount dashboard-admin -n kube-system
[k8s-master-01]# kubectl create clusterrolebinding dashboard-admin --clusterrole=cluster-admin --serviceaccount=kube-system:dashboard-admin
[k8s-master-01]# kubectl describe secrets -n kube-system $(kubectl -n kube-system get secret | awk '/dashboard-admin/{print $1}')

访问地址https://NodeIP:Port

把刚才创建管理员输出token字符串输入登录输入框

Dashboard显示的面板

7.2 部署CoreDNS

Kubernetes包含一个DNS服务器Kube-DNS，用于服务发现。此DNS服务器利用SkyDNS中的库为Kubernetes pod 和服务提供DNS请求。 yaml文件下载https://raw.githubusercontent.com/kubernetes/kubernetes/master/cluster/addons/dns/coredns/coredns.yaml.base 配置coredns.yaml

*******************************  修改一  **************************************
spec:
  # replicas: not specified here:
  # 1. In order to make Addon Manager do not reconcile this replicas parameter.
  # 2. Default is 1.
  # 3. Will be tuned in real time if DNS horizontal auto-scaling is turned on.
  replicas: 2    # 这行参数需要新增
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxUnavailable: 1
  selector:
    matchLabels:
      k8s-app: kube-dns


*******************************  修改二  **************************************
- name: coredns
        #image: registry.k8s.io/coredns/coredns:v1.8.6   # 这是默认镜像地址
        image: coredns/coredns:latest                    # 修改镜像地址，后面tag自行选择
        imagePullPolicy: IfNotPresent
        resources:
          limits:
            #memory: __DNS__MEMORY__LIMIT__
            memory: 70Mi        # 默认这处内存需要设置
          requests:
            cpu: 100m
            memory: 70Mi
        args: [ "-conf", "/etc/coredns/Corefile" ]


*******************************  修改三  **************************************
spec:
  selector:
    k8s-app: kube-dns
  clusterIP: 10.0.0.2   # 添加一个虚拟网段IP地址
  ports:
  - name: dns
    port: 53
    protocol: UDP
  - name: dns-tcp

⚠️ 注意 需要执行如下iptables策略，不然内网DNS无法正常解析 iptables -P INPUT ACCEPT iptables -P FORWARD ACCEPT iptables -P OUTPUT ACCEPT iptables -F

如果执行完CoreDNS无法正常解析DNS，尝试重启解析的Pod与service服务

创建CoreDNS并解析测试

# 创建CoreDNS
[k8s-master-01]# kubectl apply -f coredns.yaml


# 新建busybox.yaml
[k8s-master-01]# touch busybox.yaml && vim busybox.yaml
apiVersion: v1
kind: Pod
metadata:
  name: busybox1
  labels:
    app: busybox1
spec:
  containers:
  - image: busybox:1.28.4
    command:
      - sleep
      - "3600"
    imagePullPolicy: IfNotPresent
    name: busybox
  restartPolicy: Always


# 创建Pod
[k8s-master-01]# kubectl apply -f busybox.yaml


# 查看运行状态
[k8s-master-01]# kubectl get pods busybox1
NAME       READY   STATUS    RESTARTS   AGE
busybox1   1/1     Running   5          37s


# 测试解析
[k8s-master-01]# kubectl exec -ti busybox1 -- nslookup kubernetes.default
Server:    10.0.0.2
Address 1: 10.0.0.2 kube-dns.kube-system.svc.cluster.local


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

DNS解析没问题，至此单Master kubernetes集群搭建完成。

八、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

8.1 拷贝k8s-Master-01节点文件
# 先创建所需目录
[k8s-master-02]# mkdir -pv /opt/etcd/ssl
[k8s-master-02]# mkdir -pv ~/.kube/


# 切换k8s-Master-01节点
[k8s-master-01]# scp -r /opt/kubernetes root@192.168.20.22:/opt
[k8s-master-01]# scp -r /opt/etcd/ssl root@192.168.20.22:/opt/etcd
[k8s-master-01]# scp /usr/lib/systemd/system/kube* root@192.168.20.22:/usr/lib/systemd/system
[k8s-master-01]# scp /usr/local/bin/kubectl root@192.168.20.22:/usr/local/bin/
[k8s-master-01]# scp ~/.kube/config root@192.168.20.22:~/.kube/
8.2 删除证书文件及IP
[k8s-master-02]# rm -f /opt/kubernetes/ssl/kubelet*


[k8s-master-02]# sed -i 's/--bind-address=192.168.20.21/--bind-address=192.168.20.22/g' /opt/kubernetes/cfg/kube-apiserver.conf
[k8s-master-02]# sed -i 's/--advertise-address=192.168.20.21/--advertise-address=192.168.20.22/g' /opt/kubernetes/cfg/kube-apiserver.conf


[k8s-master-02]# sed -i 's/https\:\/\/192.168.20.21/https\:\/\/192.168.20.22/g' ~/.kube/config
8.3 启动并设置开机启动
[k8s-master-02]# systemctl daemon-reload
[k8s-master-02]# systemctl start kube-apiserver.service && systemctl start kube-controller-manager.service && systemctl start scheduler.service
[k8s-master-02]# systemctl enable kube-apiserver.service && systemctl enable kube-controller-manager.service && systemctl enable scheduler.service
8.4 查看集群状态
[k8s-master-02]# kubectl get cs
Warning: v1 ComponentStatus is deprecated in v1.19+
NAME                 STATUS    MESSAGE             ERROR
scheduler            Healthy   ok
controller-manager   Healthy   ok
etcd-0               Healthy   {"health":"true"}
etcd-1               Healthy   {"health":"true"}
etcd-2               Healthy   {"health":"true"}

9、部署Nginx+Keepalived高可用负载均衡器

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。

⚠️ 注意 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。

9.1 软件安装

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

Nginx也可以编译安装，灵活添加所需模块，为了进行四层转发，需要在编译时添加以下两个参数。

--with-stream
--with-stream_ssl_module
9.2 Nginx.conf配置(主备一致)
user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log;
pid /run/nginx.pid;


include /usr/share/nginx/modules/*.conf;


events {
    worker_connections 1024;
}


# 四层负载均衡，为两台Master apiserver组件提供负载均衡
stream {


    log_format  main  '$remote_addr $upstream_addr - [$time_local] $status $upstream_bytes_sent';


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


    upstream k8s-apiserver {
       server 192.168.20.21:6443;   # Master1 APISERVER IP:PORT
       server 192.168.20.22:6443;   # Master2 APISERVER IP:PORT
    }


    server {
       listen 0.0.0.0:6443; # 与其他节点复用需要注意改端口号
       proxy_pass k8s-apiserver;
    }
}


http {
    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/access.log  main;


    sendfile            on;
    tcp_nopush          on;
    tcp_nodelay         on;
    keepalive_timeout   65;
    types_hash_max_size 2048;


    include             /etc/nginx/mime.types;
    default_type        application/octet-stream;


    server {
        listen       80 default_server;
        server_name  _;


        location / {
        }
    }
}
9.3 keepalived.conf(Nginx Master)
global_defs {
   router_id NGINX_MASTER
}


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


vrrp_instance VI_1 {
    state MASTER   #主备名称别一样
    interface eno16777736  # 注意网卡名，Centos 7网卡名有的是ens33
    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 {
        192.168.20.27/24
    }
    track_script {
        check_nginx
    }
}

添加上面文件里的Nginx运行状态脚本，注意所属路径(主备节点都添加)

#!/bin/bash


RUN=$(ps aux | grep -w nginx | grep -v grep | wc -l)
if [ $RUN -eq 0 ];then
  systemctl stop keepalived.service
  exit 1
fi

别忘了添加执行权限chmod +x /etc/keepalived/check_nginx.sh

9.4 keepalived.conf(Nginx Backup)
global_defs {
   router_id NGINX_MASTER
}


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


vrrp_instance VI_1 {
    state BACKUP
    interface eno16777736
    virtual_router_id 51
    priority 90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    # 虚拟IP
    virtual_ipaddress {
        192.168.20.27/24
    }
    track_script {
        check_nginx
    }
}
9.5 启动服务并设置开机自启
systemctl daemon-reload
systemctl start nginx keepalived
systemctl enable nginx keepalived

⚠️ 注意 为了防止keepalived主备VIP出现“脑裂”情况，需要注意以下两点 (1)、确保本机SElinux是disabled状态 (2)、确保本地防火墙放行vrrp协议，如下操作： firewall-cmd –direct –permanent –add-rule ipv4 filter INPUT 0 –in-interface eno16777736 –destination 224.0.0.18 –protocol vrrp -j ACCEPT firewall-cmd –reload

9.6 Nginx+Keepalived高可用测试

显示Master节点VIP状态

显示Backup节点VIP状态

在Master节点关闭Nginx服务

观察Backup节点VIP状态

Master节点恢复Nginx服务

在k8s集群任意一个节点，使用curl查看K8s版本测试，使用VIP访问

curl -k https://192.168.20.27:6443/version
{
  "major": "1",
  "minor": "20",
  "gitVersion": "v1.20.15",
  "gitCommit": "8f1e5bf0b9729a899b8df86249b56e2c74aebc55",
  "gitTreeState": "clean",
  "buildDate": "2022-01-19T17:23:01Z",
  "goVersion": "go1.15.15",
  "compiler": "gc",
  "platform": "linux/amd64"
}

查看Nginx日志

192.168.20.24 192.168.20.21:6443 - [09/Jun/2022:05:23:57 +0800] 200 1660
192.168.20.24 192.168.20.22:6443 - [09/Jun/2022:05:25:04 +0800] 200 1935
9.7 修改所有Worker Node连接LB VIP

试想下，虽然我们增加了Master02 Node和负载均衡器，但是我们是从单Master架构扩容的，也就是说目前所有的Worker Node组件连接都还是Master01 Node，如果不改为连接VIP走负载均衡器，那么Master还是单点故障。 因此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192.168.20.21修改为192.168.20.27（VIP） 在所有Worker Node执行

sed -i 's/https\:\/\/192.168.20.21/https\:\/\/192.168.20.27/g' /opt/kubernetes/cfg/bootstrap.kubeconfig
sed -i 's/https\:\/\/192.168.20.21/https\:\/\/192.168.20.27/g' /opt/kubernetes/cfg/kubelet.kubeconfig
sed -i 's/https\:\/\/192.168.20.21/https\:\/\/192.168.20.27/g' /opt/kubernetes/cfg/kube-proxy.kubeconfig

重启所有Worker Node节点kubelet与kube-proxy服务

检查节点状态

[k8s-master-01]# kubectl get node
NAME          STATUS   ROLES    AGE     VERSION
k8s-work-01   Ready    <none>   5d14h   v1.20.15
k8s-work-02   Ready    <none>   5d13h   v1.20.15

至此，一套完整的 Kubernetes 高可用集群就部署完成了!

使用二进制包部署kubernetes V1.20集群
https://huoshen.pages.dev/cn/p/bd181034/
作者
Koevn
发布于
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CC BY-NC-SA 4.0