CentOS 7.9 环境下搭建k8s集群（一主两从）

一、硬件准备（虚拟主机）
二、环境准备
三、为所有节点安装docker
四、集群部署

一、硬件准备（虚拟主机）

角色	主机名	ip地址
master	k8s-master	192.168.112.10
node	k8s-node1	192.168.112.20
node	k8s-node2	192.168.112.30

CentOS Linux release 7.9.2009 (Core)

至少2核CPU、3GB以上内存

使用命令hostnamectl set-hostname临时修改主机名

二、环境准备

1、所有机器关闭防火墙

bash 复制代码

systemctl stop firewalld	#关闭
systemctl disable firewalld		#开机不自启
systemctl status firewalld		#查看状态

2、所有机器关闭selinux

bash 复制代码

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

3、所有机器关闭swap

bash 复制代码

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

4、所有机器上添加主机名与ip的对应关系

bash 复制代码

vim /etc/hosts

127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
192.168.112.10 k8s-master
192.168.112.20 k8s-node1
192.168.112.30 k8s-node2

5、在所有主机上将桥接的ipv4流量传递到iptables的链

bash 复制代码

cat > /etc/sysctl.d/k8s.conf << EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF

三、为所有节点安装docker

bash 复制代码

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-20.10.11 -y
systemctl start docker
systemctl enable docker

四、集群部署

1、为所有节点修改仓库，安装kubeadm、kubelet、kubectl

bash 复制代码

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 kubelet-1.22.2 kubeadm-1.22.2 kubectl-1.22.2 -y
systemctl enable kubelet && systemctl start kubelet

2、修改docker的配置（所有节点）

bash 复制代码

[root@k8s-master ~]# cat > /etc/docker/daemon.json <<EOF
> {
>   "exec-opts": ["native.cgroupdriver=systemd"]
> }
> EOF
[root@k8s-master ~]# systemctl daemon-reload
[root@k8s-master ~]# systemctl restart docker.service
[root@k8s-master ~]# systemctl restart kubelet.service
[root@k8s-master ~]# systemctl status kubelet.service

这里从节点的kubelet.service状态报code=exited, status=1/FAILURE是正常的

3、部署master节点（主节点k8s-master）

bash 复制代码

kubeadm init \
--apiserver-advertise-address=192.168.112.10 \
--image-repository registry.aliyuncs.com/google_containers \
--kubernetes-version v1.22.2 \
--control-plane-endpoint k8s-master \
--service-cidr=172.16.0.0/16 \
--pod-network-cidr=10.244.0.0/16

记得保存好这段命令是用于将一个工作节点（worker node）加入到已存在的 Kubernetes 集群中的过程。

（1）、遇到报错：

bash 复制代码

Here is one example how you may list all Kubernetes containers running in docker:
                - 'docker ps -a | grep kube | grep -v pause'
                Once you have found the failing container, you can inspect its logs with:
                - 'docker logs CONTAINERID'

error execution phase wait-control-plane: couldn't initialize a Kubernetes cluster
To see the stack trace of this error execute with --v=5 or higher

（2）、解决办法：

bash 复制代码

rm -rf /etc/containerd/config.toml
systemctl restart containerd

4、按照指示执行：

bash 复制代码

[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

5、查看kubelet.service状态

bash 复制代码

systemctl status kubelet.service

6、查看节点状态为notready

bash 复制代码

[root@k8s-master ~]# kubectl get nodes
NAME         STATUS     ROLES    AGE   VERSION
k8s-master   NotReady   <none>   67s   v1.22.2

7、安装网络插件，官方文档：https://github.com/flannel-io/flannel

bash 复制代码

# 最好手动提前拉取所需镜像
[root@k8s-master ~]# docker pull quay.io/coreos/flannel:v0.14.0
[root@k8s-master ~]# wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
[root@k8s-master ~]# kubectl apply -f kube-flannel.yml

8、添加node节点

bash 复制代码

# 为node拉取网络插件镜像
[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 byfq2h.myv4dj0yqmmjz6qx \
>         --discovery-token-ca-cert-hash sha256:f6b364e22cd4e61897a9a58583ae072c5a3724ac14f44319b5f72021614eaadf
[root@k8s-node2 ~]# kubeadm join k8s-master:6443 --token byfq2h.myv4dj0yqmmjz6qx \
>         --discovery-token-ca-cert-hash sha256:f6b364e22cd4e61897a9a58583ae072c5a3724ac14f44319b5f72021614eaadf

至此一个简单的k8s集群安装完成