设备准备

角色	主机名	IP地址
master	k8s-master	192.168.31.100
node	k8s-node1	192.168.31.101
node	k8s-node2	192.168.31.102

[root@k8s-master ~]# nmcli connection modify ens33 ipv4.addresses 192.168.31.100/24 ipv4.gateway 192.168.31.2 ipv4.dns 114.114.114.114 ipv4.method manual autoconnect yes 
[root@k8s-node1 ~]# nmcli connection modify ens33 ipv4.addresses 192.168.31.101/24 ipv4.gateway 192.168.31.2 ipv4.dns 114.114.114.114 ipv4.method manual autoconnect yes 
[root@k8s-node2 ~]# nmcli connection modify ens33 ipv4.addresses 192.168.31.102/24 ipv4.gateway 192.168.31.2 ipv4.dns 114.114.114.114 ipv4.method manual autoconnect yes

环境准备

在所有的机器上关闭防火墙和SELinux

systemctl stop firewalld
systemctl disable firewalld
sed -i 's/enforcing/disabled/' /etc/selinux/config
setenforce 0

在所有的机器上关闭交换分区swap

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

在所有的机器上添加主机名与IP对应的关系，使得互相之间可以通过主机名通信

[root@k8s-master ~]# vim /etc/hosts
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
192.168.31.100 k8s-master
192.168.31.101 k8s-node1
192.168.31.102 k8s-node2

在所有的机器上将桥接的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

在所有的机器上安装Docker

yum install wget.x86_64 -y
rm -rf /etc/yum.repos.d/*
wget -O /etc/yum.repos.d/centos7.repo http://mirrors.aliyun.com/repo/Centos-7.repo
wget -O /etc/yum.repos.d/epel-7.repo http://mirrors.aliyun.com/repo/epel-7.repo
wget -O /etc/yum.repos.d/docker-ce.repo https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
yum install docker-ce -y

启动docker

systemctl enable docker.service 
systemctl start docker.service

集群部署

配置镜像仓库kubernetes镜像-kubernetes下载地址-kubernetes安装教程-阿里巴巴开源镜像站 (aliyun.com)

为所有的机器修改仓库，安装kubeadm、kubelet、kubectl

cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF
yum install -y kubelet kubeadm kubectl
systemctl enable kubelet && systemctl start kubelet

ps: 由于官网未开放同步方式, 可能会有索引gpg检查失败的情况, 这时请用 yum install -y --nogpgcheck kubelet kubeadm kubectl 安装

修改所有机器的Docker配置

cat > /etc/docker/daemon.json <<EOF
{
"exec-opts": ["native.cgroupdriver=systemd"]
}
EOF
systemctl daemon-reload 
systemctl restart docker.service 
systemctl restart kubelet.service

部署Master

[root@k8s-master ~]# kubeadm init \
--apiserver-advertise-address=192.168.31.100 \
--image-repository registry.aliyuncs.com/google_containers \
--kubernetes-version v1.23.5 \
--control-plane-endpoint k8s-master \
--service-cidr=172.16.0.0/16 \
--pod-network-cidr=10.244.0.0/16

如果出现类似这种Kubelet version: "1.23.5" Control plane version: "1.22.2"的版本报错问题，主要是因为控制平面的版本不能低于kubelet的版本，因此只要将--kubernetes-version后的版本改为和报错信息中的kubelet的版本一样就行了

如果最后出现下述信息就代表安装完成了

Your Kubernetes control-plane has initialized successfully!

To start using your cluster, you need to run the following as a regular user:
# 可以输入的
  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:
# 如果是root用户还需要输入
  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/

You can now join any number of control-plane nodes by copying certificate authorities
and service account keys on each node and then running the following as root:
# 如果需要加入很多控制平面节点即master则需要使用下面的
  kubeadm join k8s-master:6443 --token sbw7mf.owh7u211d7fit94h \
    --discovery-token-ca-cert-hash sha256:074aa998614125525a58ca30a78337c26f6d5dac305691a35eeb819a7496c8bc \
    --control-plane 

Then you can join any number of worker nodes by running the following on each as root:
# 如果需要加入很多k8s-node节点则需要使用下面的
kubeadm join k8s-master:6443 --token sbw7mf.owh7u211d7fit94h \
    --discovery-token-ca-cert-hash sha256:074aa998614125525a58ca30a78337c26f6d5dac305691a35eeb819a7496c8bc

此时k8s-master中的镜像有下面这些

Kubernetes集群部署 - 图1

按照完成信息中的一些指示进行执行

[root@k8s-master ~]# mkdir -p $HOME/.kube
[root@k8s-master ~]# sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
[root@k8s-master ~]# sudo chown $(id -u):$(id -g) $HOME/.kube/config
[root@k8s-master ~]# export KUBECONFIG=/etc/kubernetes/admin.conf

由于之后会需要加入多个k8s-node节点，因此需要保存完成信息中的指示

[root@k8s-master ~]# vim k8s-node.token
kubeadm join k8s-master:6443 --token sbw7mf.owh7u211d7fit94h \
    --discovery-token-ca-cert-hash sha256:074aa998614125525a58ca30a78337c26f6d5dac305691a35eeb819a7496c8bc

查看节点的状态，为NotReady

[root@k8s-master ~]# kubectl get nodes
NAME         STATUS     ROLES                  AGE     VERSION
k8s-master   NotReady   control-plane,master   5m20s   v1.23.5

k8s是默认不带虚拟网络插件的，因此需要安装网络插件

# 最好手动提前拉取所需镜像
[root@k8s-master1 ~]# docker pull quay.io/coreos/flannel:v0.14.0

[root@k8s-master1 ~]# wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
[root@k8s-master1 ~]# kubectl apply -f kube-flannel.yml

# 稍等片刻，状态就为Ready了
[root@k8s-master ~]# kubectl get nodes
NAME         STATUS   ROLES                  AGE     VERSION
k8s-master   Ready    control-plane,master   9m54s   v1.23.5

将k8s-node节点加入到其中，需要用到之前保存的密钥

[root@k8s-node1 ~]# docker pull quay.io/coreos/flannel:v0.14.0
[root@k8s-node2 ~]# docker pull quay.io/coreos/flannel:v0.14.0
[root@k8s-node1 ~]# kubeadm join k8s-master:6443 --token sbw7mf.owh7u211d7fit94h \
    --discovery-token-ca-cert-hash sha256:074aa998614125525a58ca30a78337c26f6d5dac305691a35eeb819a7496c8bc 
[root@k8s-node2 ~]# kubeadm join k8s-master:6443 --token sbw7mf.owh7u211d7fit94h \
    --discovery-token-ca-cert-hash sha256:074aa998614125525a58ca30a78337c26f6d5dac305691a35eeb819a7496c8bc

查看各节点的状态

[root@k8s-master ~]# kubectl get nodes
NAME         STATUS   ROLES                  AGE   VERSION
k8s-master   Ready    control-plane,master   40m   v1.23.5
k8s-node1    Ready    <none>                 10m   v1.23.5
k8s-node2    Ready    <none>                 10m   v1.23.5

简单体验

创建Nginx容器

[root@k8s-master ~]# kubectl create deployment nginx --image=nginx
deployment.apps/nginx created

暴露对外端口

[root@k8s-master ~]# kubectl expose deployment nginx --port=80 --type=NodePort
service/nginx exposed

查看Nginx是否运行成功

[root@k8s-master ~]# kubectl get pod
NAME                     READY   STATUS    RESTARTS   AGE
nginx-85b98978db-p5mpm   1/1     Running   0          116s
[root@k8s-master ~]# kubectl get svc
NAME         TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
kubernetes   ClusterIP   172.16.0.1      <none>        443/TCP        36m
nginx        NodePort    172.16.184.54   <none>        80:31625/TCP   59s

访问测试，每台机器的IP地址都可以访问，因为每一台机器上都被设置了iptables规则

[root@k8s-master ~]# curl 192.168.31.100:31625
[root@k8s-master ~]# curl 192.168.31.101:31625
[root@k8s-master ~]# curl 192.168.31.102:31625

扩容

[root@k8s-master ~]# kubectl get pods
NAME                     READY   STATUS    RESTARTS   AGE
nginx-85b98978db-p5mpm   1/1     Running   0          20m
[root@k8s-master ~]# kubectl scale deployment nginx --replicas=3
deployment.apps/nginx scaled
[root@k8s-master ~]# kubectl get pods
NAME                     READY   STATUS    RESTARTS   AGE
nginx-85b98978db-cvj8k   1/1     Running   0          27s
nginx-85b98978db-p5mpm   1/1     Running   0          21m
nginx-85b98978db-sk9s5   1/1     Running   0          27s

可以看到2个pod在node1上，还有1个pod在node2上

Kubernetes集群部署 - 图2