测试环境

[root@localhost ~]# cat /etc/redhat-release
CentOS Linux release 7.9.2009 (Core)

kubernetes安装

参考kuberneter文档

加入节点到当前kubernetes集群可根据上述文档加入

环境配置

swapoff -a
setenforce 0
rm -rf $HOME/.kube #已安装过

安装程序

#安装docker
yum install docker -y#安装kubeadm、kubectl
#添加下载源：
cat << EOF >/etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF# 安装指定版本的kubeadm kubectl kubelet
# 查询所有版本：yum list available kubeadm --showduplicates
# 比如此处安装1.23.0的kubernetes, 需要安装对应的版本
# 否则会报错, 如: 
# this version of kubeadm only supports deploying clusters with the control plane version >= 1.27.0. Current version: v1.23.0
yum install kubeadm-1.23.0-0 kubectl-1.23.0-0 kubelet-1.23.0-0 -y

下载镜像

#使用kubeadm初始化Master节点
#执行命令下列命令查看需要下载的docker镜像及相应版本，这里的名字必须与后面的docker images中显示的名字一样，否则初始化时会失败：
kubeadm config images list#生成脚本，并将其中的版本信息填入到下列脚本：
cat << EOF >download.sh
#!/bin/bash
set -eKUBE_VERSION=v1.23.0
KUBE_PAUSE_VERSION=3.6
ETCD_VERSION=3.5.1-0
CORE_DNS_VERSION=v1.8.6GCR_URL=k8s.gcr.io
ALIYUN_URL=registry.cn-hangzhou.aliyuncs.com/google_containersimages=(kube-proxy:${KUBE_VERSION}kube-scheduler:${KUBE_VERSION}kube-controller-manager:${KUBE_VERSION}kube-apiserver:${KUBE_VERSION}pause:${KUBE_PAUSE_VERSION}etcd:${ETCD_VERSION}coredns:${CORE_DNS_VERSION}
)for imageName in ${images[@]} ; dodocker pull ${ALIYUN_URL}/$imageNamedocker tag  ${ALIYUN_URL}/$imageName ${GCR_URL}/$imageNamedocker rmi ${ALIYUN_URL}/$imageName
done
# 额外tag一下
docker tag ${GCR_URL}/coredns:v1.8.6 ${GCR_URL}/coredns/coredns:v1.8.6
EOF

初始化

reset环境

# 如果安装过则进行reset
kubeadm reset

init构建kubernetes

#使用如下命令查看初始化时的默认配置：
kubeadm config print init-defaults >init.yaml
#初始化，#可根据需要修改上一步获取到的配置，如修改kubernetes版本，以及其它ip等配置
kubeadm init --config=init.yaml# 建议直接使用此命令
kubeadm init --kubernetes-version=1.23.0 --node-name=master

异常分析：

这一步骤容易出现错误，可以根据提示进行分析，kubeadm init增加参数–v=5可以查看详细信息，如果这里还没有找到问题原因，则通过journalctl -xeu kubelet查找问题

cgroup driver报错：

# error: Failed to run kubelet" err="failed to run Kubelet: misconfiguration: kubelet cgroup driver: \"systemd\" is different from docker cgroup driver: \"cgroupfs\""# 创建配置文件 kubeadm-config.yaml, 并配置version和cgroupDriver
kind: ClusterConfiguration
apiVersion: kubeadm.k8s.io/v1beta3
kubernetesVersion: v1.23.0
---
kind: KubeletConfiguration
apiVersion: kubelet.config.k8s.io/v1beta1
cgroupDriver: cgroupfs# kubeadm reset后重新kubeadm init
kubeadm init --config=kubeadm-config.yaml

配置授权信息

上一步完成后，会有提示，可根据提示配置授权信息
也可加入worker节点到集群
提示信息：

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/.kubesudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/configsudo chown $(id -u):$(id -g) $HOME/.kube/configAlternatively, if you are the root user, you can run:export KUBECONFIG=/etc/kubernetes/admin.confYou 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 172.20.20.114:6443 --token s8qj24.jken8zoqh8hqhneq \--discovery-token-ca-cert-hash sha256:dd5f58c9ad1113daf894c79a61cadd67ded2c89ee99611ebd4f7e50dc3d89658 

如果忘记token和sha256可通过命令查询

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

配置网络插件

参考kuberneter文档

# 下载，也可以用wget https://raw.githubusercontent.com/projectcalico/calico/v3.27.3/manifests/calico.yaml
curl https://raw.githubusercontent.com/projectcalico/calico/v3.27.3/manifests/calico.yaml -O
# apply
kubectl apply -f calico.yaml

查看状态

上一步会去拉镜像等操作，可能需要一些时间

#查看是否安装成功，默认生成namespace kube-system
[root@localhost kubernetes]# kubectl get po -A
NAMESPACE     NAME                                       READY   STATUS    RESTARTS   AGE
kube-system   calico-kube-controllers-5bd579bf9c-9j8nx   1/1     Running   0          3m3s
kube-system   calico-node-7b2cv                          1/1     Running   0          3m3s
kube-system   coredns-64897985d-lrsg4                    1/1     Running   0          15m
kube-system   coredns-64897985d-qkjdz                    1/1     Running   0          15m
kube-system   etcd-master                                1/1     Running   0          15m
kube-system   kube-apiserver-master                      1/1     Running   0          15m
kube-system   kube-controller-manager-master             1/1     Running   0          15m
kube-system   kube-proxy-hgktb                           1/1     Running   0          15m
kube-system   kube-scheduler-master                      1/1     Running   0          15m
# node ready
[root@localhost kubernetes]# kubectl get node
NAME     STATUS   ROLES                  AGE   VERSION
master   Ready    control-plane,master   26m   v1.23.0

简单实例测试

由于上一步只是创建了一个节点，即只有一个主节点，kubernetes默认时不再master上运行pod的，所以需要先配置一下，允许在master上运行pod

#单节点，设置master节点也可以运行Pod，kubernetes官方默认策略是worker节点运行Pod，master节点不运行Pod。如果只是为了开发或者其他目的而需要部署单节点集群，可以通过以下的命令设置：
kubectl taint nodes --all node-role.kubernetes.io/master-
#kubectl taint node master node-role.kubernetes.io/master="":NoSchedule #将 Master 恢复成 Master Only 状态

创建nginx-deployment控制器yaml文件

cat << EOF >nginx-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:name: nginx-deploymentlabels:app: nginx
spec:replicas: 1selector:matchLabels:app: nginxtemplate:metadata:labels:app: nginxspec:containers:- name: nginximage: nginx:1.15.4ports:- containerPort: 80
EOF

创建nginx-service服务yaml文件

cat << EOF >nginx-service.yaml
apiVersion: v1
kind: Service
metadata:name: nginx-servicelabels:app: nginx
spec:type: NodePortports:- port: 80targetPort: 80nodePort: 30949selector:app: nginx
EOF

根据已创建的yaml文件生成deployment、service，这里由于未指定命名空间，所有都在default命名空间创建，若在其他空间创建的，可以增加参数-n

kubectl apply -f nginx-deployment.yaml
kubectl apply -f nginx-service.yaml

查看是否成功

kubectl get svc -n default
kubectl get deploy
kubectl get pod

结果示例

[root@localhost ~]# kubectl get svc -n default
NAME            TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)        AGE
kubernetes      ClusterIP   10.96.0.1      <none>        443/TCP        2d3h
nginx-service   NodePort    10.97.200.51   <none>        80:30949/TCP   101s
[root@localhost ~]# kubectl get deploy -n default
NAME               READY   UP-TO-DATE   AVAILABLE   AGE
nginx-deployment   1/1     1            1           2m11s
[root@localhost ~]# kubectl get pod -n default
NAME                                READY   STATUS    RESTARTS   AGE
nginx-deployment-746ccc65d8-pwcqb   1/1     Running   0          2m13s

可根据上述生成的nginx-service.yaml中的nodePort得到服务开放端口30949，然后通过如下命令访问：

[root@localhost ~]# curl localhost:30949
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>body {width: 35em;margin: 0 auto;font-family: Tahoma, Verdana, Arial, sans-serif;}
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p><p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p><p><em>Thank you for using nginx.</em></p>
</body>
</html>

查看pod日志，根据命令kubectl get pod -n default查看pod名字，然后使用 kubectl -n default logs -f 查看日志

[root@localhost ~]# kubectl get pod -n default
NAME                                READY   STATUS    RESTARTS   AGE
nginx-deployment-746ccc65d8-pwcqb   1/1     Running   0          8m12s
[root@localhost ~]# kubectl -n default logs -f nginx-deployment-746ccc65d8-pwcqb