网络上教程很多是旧版本的镜像，拉取不到。需要按照自己的情况去搭建。本文使用的kubernete版本是1.12.1。
一、环境安装
- ubuntu == 20.04
- docker == 20.10.7
- k8s == 1.21.1
教程如下：https://blog.csdn.net/M82_A1/article/details/95635705/
$ apt-get install -y kubelet=1.21.1-00 kubeadm=1.21.1-00 kubectl=1.21.1-00
# 卸载方法
$ kubeadm reset
$ apt-get remove kubelet kubeadm kubectl
禁用swap：参考 https://zhuanlan.zhihu.com/p/138554103
$ sudo swapoff -a
$ sudo vim /etc/fstab #修改/etc/fstab，注释掉swap那行，持久化生效
注册aliyun账号并且，docker login: 参考: https://help.aliyun.com/document_detail/60743.html
拉取相关的image，其中有一个bug，需要重新打tag：
# 查询需要下载的镜像
$ kubeadm config images list --config kubeadm.yaml
# 查询已经有的镜像
$ docker images
# 注意coredns会出现问题
$ docker pull registry.aliyuncs.com/google_containers/coredns:1.8.0
# 重命名
$ docker tag registry.aliyuncs.com/google_containers/coredns:1.8.0 registry.aliyuncs.com/google_containers/coredns/coredns:v1.8.0
# 删除原有镜像
$ docker rmi registry.aliyuncs.com/google_containers/coredns:1.8.0
二、k8s集群组建
目的：一个master node，一个worker node.
执行命令：
$ kubeadm init --image-repository registry.aliyuncs.com/google_containers --pod-network-cidr=10.244.0.0/16 --apiserver-advertise-address=10.112.122.9
其中10.112.122.9是master node host ip，执行结果：
Your Kubernetes control-plane has initialized successfully!
To start using your cluster, you need to run the following as a regular user:
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
Alternatively, if you are the root user, you can run:
export KUBECONFIG=/etc/kubernetes/admin.conf
You should now deploy a pod network to the cluster.
Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
https://kubernetes.io/docs/concepts/cluster-administration/addons/
Then you can join any number of worker nodes by running the following on each as root:
kubeadm join 10.112.122.9:6443 --token u4nw4p.3fxtty1sbpkyi6n0 \
--discovery-token-ca-cert-hash sha256:c1ea97710f4e5ed7722b0e293ca9f7f2db66fac1cde17d65c22a724d08c5a1af
完成初始化操作：
$ mkdir -p $HOME/.kube
$ sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
$ sudo chown $(id -u):$(id -g) $HOME/.kube/config
一个误操作和复原方法，记录
$ kubectl apply -f https://docs.projectcalico.org/manifests/calico.yaml
$ kubectl delete -f https://docs.projectcalico.org/manifests/calico.yaml
此时网络还没跑起来：
$ kubectl get pods -n kube-system
NAME READY STATUS RESTARTS AGE
coredns-545d6fc579-lxzt9 0/1 Pending 0 2m6s
coredns-545d6fc579-tx6sj 0/1 Pending 0 2m6s
etcd-hyongtaonew-precision-tower-5810 1/1 Running 0 2m21s
kube-apiserver-hyongtaonew-precision-tower-5810 1/1 Running 0 2m16s
kube-controller-manager-hyongtaonew-precision-tower-5810 1/1 Running 0 2m16s
kube-proxy-d5b69 1/1 Running 0 2m6s
kube-scheduler-hyongtaonew-precision-tower-5810 1/1 Running 0 2m16s
CNI网络部署
# 这个yaml文件有700多行 不复制了
$ wget https://docs.projectcalico.org/v3.10/manifests/calico.yaml
$ kubectl apply -f calico.yaml
稍等片刻后，coredns等服务都处于running状态了：
$ kubectl get pods -n kube-system
NAME READY STATUS RESTARTS AGE
calico-kube-controllers-7c5dd46f7d-bm5m5 1/1 Running 0 77s
calico-node-pl2cr 0/1 Running 0 77s
coredns-545d6fc579-lxzt9 1/1 Running 0 7m23s
coredns-545d6fc579-tx6sj 1/1 Running 0 7m23s
etcd-hyongtaonew-precision-tower-5810 1/1 Running 0 7m38s
kube-apiserver-hyongtaonew-precision-tower-5810 1/1 Running 0 7m33s
kube-controller-manager-hyongtaonew-precision-tower-5810 1/1 Running 0 7m33s
kube-proxy-d5b69 1/1 Running 0 7m23s
kube-scheduler-hyongtaonew-precision-tower-5810 1/1 Running 0 7m33s
构建Worker Node
# 在worker node执行下面的命令
$ kubeadm join 10.112.122.9:6443 --token u4nw4p.3fxtty1sbpkyi6n0 --discovery-token-ca-cert-hash sha256:c1ea97710f4e5ed7722b0e293ca9f7f2db66fac1cde17d65c22a724d08c5a1af
# 在master node执行
$ kubectl get nodes
NAME STATUS ROLES AGE VERSION
amdlattice-precision-tower-5810 Ready 2m v1.21.1
hyongtaonew-precision-tower-5810 Ready control-plane,master 14m v1.21.1
启动一个Nginx服务
$ kubectl create deployment nginx --image=nginx
deployment.apps/nginx created
$ kubectl expose deployment nginx --port=80 --type=NodePort # 暴露80端口
service/nginx exposed
$ kubectl get pod,svc # 查看对外端口
NAME READY STATUS RESTARTS AGE
pod/nginx-6799fc88d8-fzhnv 1/1 Running 0 29s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/flaskapp-1 NodePort 10.99.22.77 5000:30005/TCP 3m15s
service/kubernetes ClusterIP 10.96.0.1 443/TCP 19m
service/nginx NodePort 10.109.12.14 80:32101/TCP 16s
最后访问http://10.117.169.29:32101/的结果图：
10.117.169.29为worker node的真实ip。
nginx.png
三、几个相关的yaml文件
kubeadm.yaml的内容，没有用到，留作参考：
apiVersion: kubeadm.k8s.io/v1beta2
kind: ClusterConfiguration
controllerManager:
extraArgs:
horizontal-pod-autoscaler-use-rest-clients: "true"
horizontal-pod-autoscaler-sync-period: "10s"
node-monitor-grace-period: "10s"
apiServer:
extraArgs:
runtime-config: "api/all=true"
kubernetesVersion: v1.21.1
imageRepository: registry.aliyuncs.com/google_containers