kubeadm是官方社区推出的一个用于快速部署 kubernetes 集群的工具，这个工具能通过两条指令完成一个kubernetes集群的部署；

Kubernetes部署环境准备（每台同样操作）

1. 关闭防火墙

systemctl stop firewalld
systemctl disable firewalld

2. 关闭selinux

#永久
sed -i 's/enforcing/disabled/' /etc/selinux/config  
#临时
setenforce 0  

3. 关闭swap（k8s禁止虚拟内存以提高性能）

#永久
sed -ri 's/.*swap.*/#&/' /etc/fstab 
#临时
swapoff -a

4. 在master添加hosts

cat >> /etc/hosts << EOF
192.168.116.103 k8smaster
192.168.116.104 k8snode
EOF

5. 设置网桥参数

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

6. 时间同步

yum install ntpdate -y
ntpdate time.windows.com

Kubernetes安装具体步骤

1、创建一个Master节点：
kubeadm init
2、将Node节点加入到Master集群中：
$ kubeadm join <Master节点的IP和端口>

安装 Docker（每台同样操作）

1. 安装Docker

1. 下载docker源，安装docker v20.10.12
   先卸载docker旧版本

systemctl stop docker
 yum list installed |grep docker
rpm -qa |grep docker
yum -y remove docker-ce-18.06.1.ce-3.el7.x86_64
# 再次查看
rpm -qa |grep docker
#删除docker文件夹
rm -rf /var/lib/docker

yum install wget -y
wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo
yum install docker-ce-20.10.12 -y

2. 开机启动和启动docker
   systemctl enable docker.service
   systemctl start docker

3. 配置加速器加速下载
   vi /etc/docker/daemon.json

{
"registry-mirrors": ["https://hdi5v8p1.mirror.aliyuncs.com/"]
}

安装 kubeadm、kubelet 和 kubectl

1. 新增Kubernets阿里云YUM源

cat > /etc/yum.repos.d/kubernetes.repo << EOF
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=0
repo_gpgcheck=0
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF

2. 安装 kubeadm 1.23.1-0 版本
   yum install kubeadm-1.23.1-0 kubectl-1.23.1-0 kubelet-1.23.1-0 -y
3. 开机启动
   systemctl enable kubelet.service
4. 查看有没有安装：

yum list installed | grep kubelet
yum list installed | grep kubeadm
yum list installed | grep kubectl

查看版本
kubelet --version
Kubernetes v1.23.1

Kubelet：运行在cluster所有节点上，负责启动POD和容器；
Kubeadm：用于初始化cluster的一个工具；
Kubectl：kubectl是kubenetes命令行工具，通过kubectl可以部署和管理应用，查看各种资源，创建，删除和更新组件；

重启centos服务器
reboot

部署Kubernetes Master主节点

1. Master 初始化

kubeadm init --apiserver-advertise-address=192.168.116.103 --image-repository registry.aliyuncs.com/google_containers --kubernetes-version v1.23.1 --service-cidr=10.66.0.0/18 --pod-network-cidr=10.88.0.0/20

报错，

kubeadmin init 报错
两台服务器执行 kubeadm reset 再执行上面 kubeadm init命令

查看出错日志 journalctl -xefu kubelet

# -xefu说明
-x --catalog             Add message explanations where available
-e --pager-end           Immediately jump to the end in the pager
-f --follow              Follow the journal
-u --unit=UNIT           Show logs from the specified unit

在万不得已操作 忽略错误 --ignore-preflight-errors=all
kubeadm init --apiserver-advertise-address=192.168.116.103 --image-repository registry.aliyuncs.com/google_containers --kubernetes-version v1.23.1 --service-cidr=10.66.0.0/18 --pod-network-cidr=10.88.0.0/20 --ignore-preflight-errors=all

2. master机器上执行
   kubeadm成功后显示下面提示

Your Kubernetes control-plane has initialized successfully!

To start using your cluster, you need to run the following as a regular user:
# 执行下面三行命令
  mkdir -p $HOME/.kube
  sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
  sudo chown $(id -u):$(id -g) $HOME/.kube/config

Alternatively, if you are the root user, you can run:
# 执行下面一行命令
  export KUBECONFIG=/etc/kubernetes/admin.conf

You should now deploy a pod network to the cluster.
Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
  https://kubernetes.io/docs/concepts/cluster-administration/addons/
#执行下面代码
kubectl apply -f https://raw.githubusercontent.com/flannel-io/flannel/master/Documentation/kube-flannel.yml

Then you can join any number of worker nodes by running the following on each as root:
# 其他nodes加入到master，执行下面代码
kubeadm join 192.168.116.103:6443 --token iobdu9.nzpsqo600hfukwk8 \
    --discovery-token-ca-cert-hash sha256:61a43240406a53fcbda25158be98cee216aa32bca051f48c480f2c245cd9f154

查看是否成功下载相关镜像

[root@k8smaster ~]# docker images
REPOSITORY                                                        TAG       IMAGE ID       CREATED        SIZE
rancher/mirrored-flannelcni-flannel                               v0.16.1   404fc3ab6749   12 days ago    69.9MB
registry.aliyuncs.com/google_containers/kube-apiserver            v1.23.1   b6d7abedde39   4 weeks ago    135MB
registry.aliyuncs.com/google_containers/kube-proxy                v1.23.1   b46c42588d51   4 weeks ago    112MB
registry.aliyuncs.com/google_containers/kube-controller-manager   v1.23.1   f51846a4fd28   4 weeks ago    125MB
registry.aliyuncs.com/google_containers/kube-scheduler            v1.23.1   71d575efe628   4 weeks ago    53.5MB
registry.aliyuncs.com/google_containers/etcd                      3.5.1-0   25f8c7f3da61   2 months ago   293MB
rancher/mirrored-flannelcni-flannel-cni-plugin                    v1.0.0    cd5235cd7dc2   2 months ago   9.03MB
registry.aliyuncs.com/google_containers/coredns                   v1.8.6    a4ca41631cc7   3 months ago   46.8MB
registry.aliyuncs.com/google_containers/pause                     3.6       6270bb605e12   4 months ago   683kB

查看是否成功kubectl get nodes

[root@k8smaster ~]# kubectl get nodes
NAME        STATUS   ROLES                  AGE   VERSION
k8smaster   Ready    control-plane,master   53m   v1.23.1