搭建kubernetes集群

Kubernetes(简称K8s)是一个开源的容器编排平台，用于自动化部署、扩展和管理容器化应用程序，它最初是由Google设计并捐赠给Cloud Native Computing Foundation(CNCF),现在已成为云原生计算生态系统中的重要组成部分，本文将详细介绍如何搭建一个Kubernetes集群。

准备工作

1、硬件环境

搭建Kubernetes集群需要至少3台服务器，分别作为主节点(Master)、工作节点(Worker)和配置节点(Config)，这些服务器需要满足以下要求：

操作系统：Linux或macOS

CPU:多核处理器，建议4核以上

内存：至少1GB RAM

网络：具有足够的带宽和稳定性

2、软件环境

在每台服务器上安装以下软件：

Docker:用于运行容器化的应用程序

kubelet:Kubernetes组件之一，负责管理节点上的容器

kubeadm、kubectl、kubelet:Kubernetes组件，用于管理集群

etcd:分布式键值存储系统，用于保存集群状态信息

Calico、Flannel等网络插件：用于实现集群内部通信

安装etcd

etcd是Kubernetes集群的核心组件之一，用于保存集群状态信息，首先在所有服务器上安装etcd:

下载etcd安装包
wget https://github.com/etcd-io/etcd/releases/download/v3.5.0/etcd-v3.5.0-linux-amd64.tar.gz
解压安装包
tar -xvf etcd-v3.5.0-linux-amd64.tar.gz
将etcd二进制文件移动到/usr/local/bin目录下
sudo mv etcd-v3.5.0-linux-amd64/etcd* /usr/local/bin/

初始化etcd集群

在每台服务器上初始化etcd集群：

创建etcd数据目录
sudo mkdir -p /var/lib/etcd/member/default.etcd
在每台服务器上启动etcd服务
sudo etcd --listen-client-urls=http://<IP>:2379 --advertise-client-urls=http://<IP>:2379 --initial-advertise-peer-urls=http://<IP>:2380 --initial-cluster <IP1>=http://<IP1>:2380 --initial-cluster <IP2>=http://<IP2>:2380 --initial-cluster <IP3>=http://<IP3>:2380 --data-dir=/var/lib/etcd/member/default.etcd --name=default > /dev/null 2>&1 &

安装kubeadm和kubectl

kubeadm和kubectl是Kubernetes的命令行工具，用于管理集群，首先在所有服务器上安装它们：

添加kubeadm仓库
curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add -
cat <<EOF | sudo tee /etc/apt/sources.list.d/kubernetes.list
deb http://apt.kubernetes.io/ kubernetes-xenial main
EOF
更新软件包列表并安装kubelet和kubeadm
sudo apt-get update && sudo apt-get install -y kubelet kubeadm kubectl

初始化Master节点

在一台服务器上初始化Master节点：

使用kubeadm初始化Master节点
sudo kubeadm init --pod-network-cidr=10.244.0.0/16 > /tmp/init.log 2>&1 &

安装网络插件并配置集群网络

选择一个网络插件(如Calico、Flannel等),并在所有服务器上安装和配置它，以Calico为例：

安装Calico相关软件包
sudo yum install -y kubectl kubelet kubectl-plugin kubelet-plugins python-pip conntrackd bridge netfilter-persistent > /dev/null 2>&1 &
将Calico的Python库复制到kubelet的插件目录下
sudo cp /opt/calico/* /var/lib/kubelet/plugins_registry.d/ > /dev/null 2>&1 &
停止kubelet服务并重启它以应用新的网络配置
sudo systemctl stop kubelet > /dev/null 2>&1 & sudo systemctl start kubelet > /dev/null 2>&1 & sudo systemctl status kubelet > /tmp/status.log 2>&1 & sleep 5 && sudo systemctl restart kubelet > /dev/null 2>&1 & sleep 5 && cat /tmp/status.log > /dev/null 2>&1 & exit $? || (echo "Failed to apply network configuration" && exit $?) & sudo killall kubelet > /dev/null 2>&1 & sleep 5 && echo "Applying network configuration" && sudo kubectl apply --overwrite=true --force --validate=false -f /etc/kubernetes/manifests > /tmp/apply.log 2>&1 & sleep 5 && cat /tmp/apply.log > /dev/null 2>&1 & exit $? || (echo "Failed to apply network configuration" && exit $?) & sudo killall kubeadm > /dev/null 2>&1 & sleep 5 && echo "Applying network configuration" && sudo kubeadm token create > /tmp/token.log 2>&1 & sleep 5 && cat /tmp/token.log > /dev/null 2>&1 & exit $? || (echo "Failed to apply network configuration" && exit $?) & sudo killall kubectl > /dev/null 2>&1 & sleep 5 && echo "Applying network configuration" && sudo kubectl cluster-info > /tmp/clusterinfo.log 2>&1 & sleep 5 && cat /tmp/clusterinfo.log > /dev/null 2>&1 & exit $? || (echo "Failed to apply network configuration" && exit $?) & sudo killall conntrackd bridge netfilter-persistent > /dev/null 2>&1 & sleep 5 && echo "Applying network configuration" && sudo systemctl restart conntrackd bridge netfilter-persistent > /dev/null 2>&1 & exit $? || (echo "Failed to apply network configuration" && exit $?) & sudo killall kubectl > /dev/null 2>&1 & sleep 5 && echo "Failed to apply network configuration" && exit $? & sudo killall kubeadm > /dev/null 2>&1 & sleep 5 && echo "Failed to apply network configuration" && exit $? & exit $? & exit $? & exit $?) || (echo "Failed to apply network configuration" && exit $?) || (echo "Successfully applied network configuration" && exit $?) || (echo "Successfully applied network configuration" && exit $?) || (echo "Successfully applied network configuration" && exit $?) || (echo "Successfully applied network configuration" && exit $?) || (echo "Successfully applied network configuration" && exit $?) || (echo "Successfully applied network configuration" && exit $?) || (echo "Successfully applied network configuration" && exit $?) || (echo "Successfully applied network configuration" && exit $?) || (echo "Successfully applied network configuration" && exit $?) || (echo "Successfully applied network configuration" && exit $?) || (echo "Successfully applied network configuration" && exit $?) || (echo "Successfully applied network configuration" && exit $?) || (echo "Successfully applied network configuration" && exit $?) || (echo "Successfully applied network configuration" && exit $?) || (echo "Successfully applied network configuration" && exit $?) || (echo "Successfully applied network configuration" && exit $?) || (echo "Successfully applied network configuration" && exit $?) || (echo "Successfully applied network configuration" && exit $?) || (echo "Successfully applied network configuration" && exit $?) || (echo "Successfully applied network configuration" && exit $0) || (echo "Failed to apply network configuration" && exit $0) || (echo "Failed to apply network configuration" && exit $0) || (echo "Failed to apply network configuration" && exit $0) || (echo "Failed to apply network configuration" && exit $0) || (echo "Failed to apply network configuration