kubeadm方式搭建k8s环境 kubernetes

1.环境信息三台centos7.9虚机
192.168.56.102 node1 (2个cpu)
192.168.56.103 node2
192.168.56.104 node3
设置三台机器间免密登录

ssh-keygen -t rsa~/.ssh/cat~/.ssh/id_rsa.pub>~/.ssh/authorized_keyschmod 700~/.sshchmod 600~/.ssh/authorized_keysssh-copy-id -i~/.ssh/id_rsa.pub-p22root@node1

修改主机名

hostname node1 //临时修改 hostnamectl set-hostname node1 //永久修改

禁用防火墙

systemctl stop firewalldsystemctl disable firewalld

禁用selinux

setenforce 0//临时关闭sed -i "s/SELINUX=enforcing/SELINUX=disabled/g" /etc/selinux/config //永久关闭

禁用缓冲区

swapoff -a/etc/fstab//注释swap

安装docker

安装工具和驱动 yum install -y yum-utils device-mapper-persistent-data lvm2添加yum源 yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo启用源 yum-config-manager --enable docker-ce-nightly卸载历史版本 yum remove docker docker-common docker-selinux docker-engine docer-io安装docker yum install docker-ce-19.03.15 docker-ce-cli-19.03.15 containerd.io-19.03.15 -y//指定版本为19.03 启动docker systemctl start docker systemctl enable docker

修改/etc/docker/daemon.json

{ "exec-opts": ["native.cgroupdriver=systemd"], "registry-mirrors":["https://docker.mirrors.ustc.edu.cn"] }

scp daemon.json root@node2:/etc/docker/
scp daemon.json root@node3:/etc/docker/
添加yum源
/etc/yum.repo.d/k8s.repo

[kubernetes] name=kubernetes enabled=1 baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/ gpgcheck=1 repo_gpgcheck=0 gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg

yum clean all
yum makecache
2.安装k8s yum search kubeadm --showduplicates
三个机器分别执行

yum install kubeadm-1.20.9-0 kubectl-1.20.9-0 kubelet-1.20.9-0 -ysystemctl start kubelet systemctl enable kubelet

在master节点上初始化

kubeadm init \ --apiserver-advertise-address 192.168.56.102 \ --image-repository registry.aliyuncs.com/google_containers \ --kubernetes-version v1.20.9 \ --service-cidr 10.1.0.0/16 \ --pod-network-cidr 10.244.0.0/16--------------------------------------------------------------------- --apiserver-advertise-address 192.168.56.102//主机的ip --image-repository registry.aliyuncs.com/google_containers //各个组件镜像仓库 --kubernetes-version v1.20.9 //k8s版本 --service-cidr 10.1.0.0/16 //service网段 --pod-network-cidr 10.244.0.0/16 //pod的网段

kubeadm init完成后

mkdir -p $HOME/.kube sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config sudo chown $(id -u):$(id -g) $HOME/.kube/configkubeadm join 192.168.56.102:6443 --token 9ei6kq.imr068aa8mvphhvt \ --discovery-token-ca-cert-hash sha256:07093c3ae6cddb40a32b9648522248d4b02bd27a0e4338f525031663c4fd2aa2

kubectl get nodes

[root@localhost kubernetes]# kubectl get nodes NAMESTATUSROLESAGEVERSION localhost.localdomainNotReadycontrol-plane,master17mv1.20.9

kubectl get pod -A

NAMESPACENAMEREADYSTATUSRESTARTSAGE kube-systemcoredns-7f89b7bc75-76xh80/1Pending019m kube-systemcoredns-7f89b7bc75-pkzzm0/1Pending019m kube-systemetcd-localhost.localdomain1/1Running019m kube-systemkube-apiserver-localhost.localdomain1/1Running019m kube-systemkube-controller-manager-localhost.localdomain1/1Running019m kube-systemkube-proxy-7k48f1/1Running019m kube-systemkube-scheduler-localhost.localdomain1/1Running019m

安装flannel网络插件

kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

3.大功告成

[root@localhost kubelet]# kubectl get nodes NAMESTATUSROLESAGEVERSION localhost.localdomainReadycontrol-plane,master31mv1.20.9 node2NotReady3m39sv1.20.9 node3Ready3m19sv1.20.9

4.遇见的错误 A. kebelet 启动不起来

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原因是cgroup类型不对

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在docker daemon.json中添加

"exec-opts": ["native.cgroupdriver=systemd"],

然后还是起不来

journalctl -xeu kubelet | less错误日志 localhost.localdomain kubelet[32128]: F0729 00:04:15.11217032128 server.go:198] failed to load Kubelet config file /var/lib/kubelet/config.yaml, error failed to read kubelet config file "/var/lib/kubelet/config.yaml", error: open /var/lib/kubelet/config.yaml: no such file or directory

需要在kubeadm init之后就可以起来了
B. 从节点没有admin.conf文件

mkdir -p $HOME/.kube [root@localhost ~]#sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config cp: 无法获取"/etc/kubernetes/admin.conf" 的文件状态(stat): 没有那个文件或目录 [root@localhost ~]#sudo chown $(id -u):$(id -g) $HOME/.kube/config chown: 无法访问"/root/.kube/config": 没有那个文件或目录

从主节点scp一份过去
C. kube-flannel.yml文件获取不到的话，可以直接下载下来
kubectl apply 报错

The connection to the server localhost:8080 was refused - did you specify the right host or port?echo "export KUBECONFIG=/etc/kubernetes/admin.conf" >> /etc/profile source /etc/profile 即可

D. docker启动不起来
错误之处

"exec-opts": ["native.cgroupdriver=systemd"], 写成了 -> "exe-opts": ["native.cgroupdriver=systemd"],

E. master节点 kubeadm join信息丢失了

----- kubeadm token create --print-join-command ---------- kubeadm token list kubeadm token create --ttl 0 openssl x509 -pubkey -in /etc/kubernetes/pki/ca.crt | openssl rsa -pubin -outform der 2>/dev/null | openssl dgst -sha256 -hex | sed 's/^.* //' -----

F. join出错

kubeadm join 192.168.56.105:6443 --token kby4kb.8pk6i96jyuyqy9q1--discovery-token-ca-cert-hash sha256:55a6876fb90e37679db74823ab8d469dabbe59ffa5ec927f1e6dc2ea16483732 [preflight] Running pre-flight checks [WARNING Service-Docker]: docker service is not enabled, please run 'systemctl enable docker.service' [preflight] Reading configuration from the cluster... [preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml' error execution phase kubelet-start: a Node with name "localhost.localdomain" and status "Ready" already exists in the cluster. You must delete the existing Node or change the name of this new joining Node To see the stack trace of this error execute with --v=5 or higher

【kubeadm方式搭建k8s环境】因为我的虚拟机是从同一台机器上克隆过来的，主机名都一样，所以需要修改一下主机名