从零搭建K8S测试集群 (2)

这是一种简单的网络模型，虚拟机和外部环境完全断开，只允许虚拟机之间互相访问，用的比较少

小结 Model VM -> host host -> VM VM <-> VM VM -> Internet Internet -> VM
Bridged   +   +   +   +   +  
NAT   +   Port Forwarding   -   +   Port Forwarding  
NAT Network   +   Port Forwarding   +   +   Port Forwarding  
Host-only   +   +   +   -   -  
Internal   -   -   +   -   -  
关于vagrant的网络

参考文档 https://www.vagrantup.com/docs/networking

vagrant支持3种网络配置，可以在Vagrantfile中进行配置：

端口映射，比如访问本机的8080端口、转发到虚拟机的80端口（默认为tcp，如果需要转发udp则指定Protocol为udp）

config.vm.network "forwarded_port", guest: 80, host: 8080

私有网络，对应Host-only网络，允许主机访问虚拟机，以及虚拟机之间互相访问，其它机器无法访问虚拟机，安全性高

config.vm.network "private_network", ip: "192.168.21.4"

共有网络，对应bridge网络，相当于一个独立的网络设备

config.vm.network "public_network", ip: "192.168.1.120" docker安装

docker官方文档 https://docs.docker.com/engine/install/

设置官方的软件源

$ sudo yum install -y yum-utils $ sudo yum-config-manager \ --add-repo \ https://download.docker.com/linux/centos/docker-ce.repo

安装docker引擎

$ sudo yum install docker-ce docker-ce-cli containerd.io

启动docker

$ sudo systemctl start docker k8s安装

k8s官方文档 https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/install-kubeadm/

确保 iptables 工具不使用 nftables 后端

update-alternatives --set iptables /usr/sbin/iptables-legacy update-alternatives --set ip6tables /usr/sbin/ip6tables-legacy update-alternatives --set arptables /usr/sbin/arptables-legacy update-alternatives --set ebtables /usr/sbin/ebtables-legacy

设置源，并安装 kubelet kubeadm kubectl

cat <<EOF > /etc/yum.repos.d/kubernetes.repo [kubernetes] name=Kubernetes baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64 enabled=1 gpgcheck=1 repo_gpgcheck=1 gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg EOF # 将 SELinux 设置为 permissive 模式（相当于将其禁用） setenforce 0 sed -i 's/^SELINUX=enforcing$/SELINUX=permissive/' /etc/selinux/config yum install -y kubelet kubeadm kubectl --disableexcludes=kubernetes systemctl enable --now kubelet 初始化集群 kubeadm init

在主节点上执行kubeadm初始化

[root@localhost vagrant]# kubeadm init [init] Using Kubernetes version: v1.20.0 [preflight] Running pre-flight checks [WARNING Service-Docker]: docker service is not enabled, please run 'systemctl enable docker.service' [WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/ [WARNING SystemVerification]: this Docker version is not on the list of validated versions: 20.10.1. Latest validated version: 19.03 error execution phase preflight: [preflight] Some fatal errors occurred: [ERROR NumCPU]: the number of available CPUs 1 is less than the required 2 [ERROR Mem]: the system RAM (486 MB) is less than the minimum 1700 MB [ERROR FileContent--proc-sys-net-bridge-bridge-nf-call-iptables]: /proc/sys/net/bridge/bridge-nf-call-iptables contents are not set to 1 [ERROR Swap]: running with swap on is not supported. Please disable swap [preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...` To see the stack trace of this error execute with --v=5 or higher

docker service is not enabled的告警，直接执行systemctl enable docker.service解决，docker会被设置为开机自启动

cgroupfs 问题告警，意思是systemd作为cgroup驱动更加稳定，让你用这个，不同的cri的设置可以参考https://kubernetes.io/docs/setup/cri/

docker版本问题告警，我的docker版本过新了，官方还没有测试过，最后一个验证过的版本是19.03

Error部分CPU和内存不足的问题，打开VirtualBox，在虚拟机的设置中将CPU的核数调整为2或以上、内存大小调整为1700MB或以上即可