K8S集群搭建
一、 环境和版本
1. 操作系统
干干静静的centos7系统，选取的是mini的iso最小化安装
# cat /etc/centos-release
CentOS Linux release 7.3.1611 (Core)
# cat /proc/version
Linux version 3.10.0-514.el7.x86_64 (builder@kbuilder.dev.centos.org) (gcc version 4.8.5 20150623 (Red Hat 4.8.5-11) (GCC) ) #1 SMP Tue Nov 22 16:42:41 UTC 2016
2. K8S版本
K8S使用的当前（现在是2021-04-07）最新版本：v1.20。官方教程：https://kubernetes.io/zh/docs/home/。安装方式采用kubeadm安装。
3. 集群环境
最少2个节点，其中1个节点作为master节点，其他节点作为node节点，本例中：
- 10.10.2.251，master节点
- 10.10.2.252，node节点
- 10.10.2.253，node节点
二、 安装
1. 设置host
# ssh root@10.10.2.251 # hostnamectl set-hostname k8s-1 # exit # ssh root@10.10.2.252 # hostnamectl set-hostname k8s-2 # exit # ssh root@10.10.2.252 # hostnamectl set-hostname k8s-3 # exit
2. 所有节点执行准备
2.1 关闭防火墙和selinux
# setenforce 0 # sed -i 's|SELINUX=\(.*\)|SELINUX=disabled|g' /etc/selinux/config # systemctl stop firewalld # systemctl disable firewalld
2.2 配置docker的yum源
# curl -o /etc/yum.repos.d/docker-ce.repo https://download.docker.com/linux/centos/docker-ce.repo # sudo sed -i 's+download.docker.com+opentuna.cn/docker-ce+' /etc/yum.repos.d/docker-ce.repo
2.3 安装docker-ce
# yum install -y docker-ce
2.4 启动docker服务
# systemctl start docker
# systemctl enable docker
2.5 关闭swap
# swapoff -a # vim /etc/fstab
将有swap那行注释掉
2.6 配置K8S的yum源
# vim /etc/yum.repos.d/kubernetes.repo
输入一下内容保存 [kubernetes]
name=kubernetes
baseurl=https://opentuna.cn/kubernetes/yum/repos/kubernetes-el7-$basearch
enabled=1
2.7 安装kubelet、kubeadm、kubectl
# yum install -y kubelet kubeadm kubectl --nogpgcheck
2.8 启动kubelet服务
# systemctl start kubelet
# systemctl enable kubelet
2.9 获取K8S所需的docker镜像
执行kubeadm config images list查看K8S需要的镜像，并参照如下方式获取镜像
# docker pull registry.aliyuncs.com/google_containers/kube-apiserver:v1.20.5 # docker pull registry.aliyuncs.com/google_containers/kube-controller-manager:v1.20.5 # docker pull registry.aliyuncs.com/google_containers/kube-scheduler:v1.20.5 # docker pull registry.aliyuncs.com/google_containers/kube-proxy:v1.20.5 # docker pull registry.aliyuncs.com/google_containers/pause:3.2 # docker pull registry.aliyuncs.com/google_containers/etcd:3.4.13-0 # docker pull registry.aliyuncs.com/google_containers/coredns:1.7.0 # docker tag registry.aliyuncs.com/google_containers/kube-apiserver:v1.20.5 k8s.gcr.io/kube-apiserver:v1.20.5 # docker tag registry.aliyuncs.com/google_containers/kube-controller-manager:v1.20.5 k8s.gcr.io/kube-controller-manager:v1.20.5 # docker tag registry.aliyuncs.com/google_containers/kube-scheduler:v1.20.5 k8s.gcr.io/kube-scheduler:v1.20.5 # docker tag registry.aliyuncs.com/google_containers/kube-proxy:v1.20.5 k8s.gcr.io/kube-proxy:v1.20.5 # docker tag registry.aliyuncs.com/google_containers/pause:3.2 k8s.gcr.io/pause:3.2 # docker tag registry.aliyuncs.com/google_containers/etcd:3.4.13-0 k8s.gcr.io/etcd:3.4.13-0 # docker tag registry.aliyuncs.com/google_containers/coredns:1.7.0 k8s.gcr.io/coredns:1.7.0
3. master节点执行创建集群
3.1 初始化集群
# kubeadm init --pod-network-cidr=10.244.0.0/16
注意执行成功后类似如下输出，复制下来
kubeadm join 10.10.2.251:6443 --token 2dhvds.4yd881szk64kqxoo --discovery-token-ca-cert-hash sha256:5435c5cbfbef0e00f5fd7b96c325771adc5a8f5591a7799939861bde6d0f557f
3.2 执行命令
# vi /etc/profile
增加如下一行，并保存
export KUBECONFIG=/etc/kubernetes/admin.conf
# source /etc/profile
3.3 安装网络插件
# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
4. 将node节点加入集群
执行3.1步输出内容
# ssh root@10.10.2.252 # kubeadm join 10.10.2.251:6443 --token 2dhvds.4yd881szk64kqxoo --discovery-token-ca-cert-hash sha256:5435c5cbfbef0e00f5fd7b96c325771adc5a8f5591a7799939861bde6d0f557f # exit # ssh root@10.10.2.253 # kubeadm join 10.10.2.251:6443 --token 2dhvds.4yd881szk64kqxoo --discovery-token-ca-cert-hash sha256:5435c5cbfbef0e00f5fd7b96c325771adc5a8f5591a7799939861bde6d0f557f # exit
5. 查看集群状态
# kubectl get nodes NAME STATUS ROLES AGE VERSION k8s-1 Ready control-plane,master 15m v1.20.5 k8s-2 Ready <none> 6m48s v1.20.5 k8s-3 Ready <none> 7m35s v1.20.5
