Centos7在线安装k8s

系统与版本

Centos7，Docker 20.10.9，kubernates 1.23.0

安装kubeadm

按照[官方的指引](https://kubernetes.io/zh/docs/setup/production-environment/tools/kubeadm/ )，我们选用`kubeadm`进行集群部署.

硬件条件

内存2G，CPU2核
关闭firewall,iptables

具体可以查看网上方法
允许 iptables 检查桥接流量
```
cat <
```

 
   关闭swap
 # 临时关闭，重启以后会重新开启
swapoff -a
# 检查是否关闭
free -m
# 如下关闭成功
[root@localhost ~]# free -m
              total        used        free      shared  buff/cache   available
Mem:           1819         260        1268           9         290        1406
Swap:             0           0           0
 vi /etc/fstab
#
# /etc/fstab
# Created by anaconda on Wed Sep  1 15:01:27 2021
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
UUID=e95686df-e97a-409f-968e-df388b13a239 /                       xfs     defaults        0 0
UUID=3f5292fa-ab79-4e86-b036-27be00d2d84e /boot                   xfs     defaults        0 0
# 注释掉swap
#UUID=e2fd5a6a-0422-43b4-b3d3-c57c50c89b84 swap                    swap    defaults        0 0
# 保存
wq
# 重启主机
# 检查是否关闭
free -m
# 如下固化关闭成功
[root@localhost ~]# free -m
              total        used        free      shared  buff/cache   available
Mem:           1819         260        1268           9         290        1406
Swap:             0           0           0
  
   安装kubeadm
 cat <
 
 
   配置host(选做，如果不做，以后的操作使用IP操作)
 $ vi /etc/hosts
192.168.234.129     k8s-master
192.168.234.130     k8s-node1
192.168.234.131     k8s-node2
#保存
$ wq
  
   初始化k8s集群 
    
     集群资源分配 
      
       
        
        角色 
        IP 
        
       
       
        
        master 
        192.168.234.129 
        
        
        node1 
        192.168.234.130 
        
        
        node2 
        192.168.234.131 
        
       
     
  
     确认各主机中kubelet处于正常运行（选做，kubeadm init初始化失败时排错 ）
 $ systemctl status kubelet # 查看状态，如果没开启就要开启
● kubelet.service - kubelet: The Kubernetes Node Agent
   Loaded: loaded (/usr/lib/systemd/system/kubelet.service; enabled; vendor preset: disabled)
  Drop-In: /usr/lib/systemd/system/kubelet.service.d
           └─10-kubeadm.conf
   Active: active (running) since 六 2021-12-11 14:30:05 CST; 2s ago
     Docs: https://kubernetes.io/docs/
 Main PID: 10469 (kubelet)
    Tasks: 11
   Memory: 26.3M
   CGroup: /system.slice/kubelet.service
           └─10469 /usr/bin/kubelet
 
      
      kubelet不是启动状态，使用journalctl -xeu kubelet命令检查启动失败原因 
       
        kubelet cgroup driver: "systemd" is different from docker cgroup
 上述原因是由于kubelet cgroup driver与docker cgroup driver不匹配，可以修改docker的cgroup driver与k8s的一致。
 编辑/etc/docker/daemon.json，加入以下配置
 {
    ...
    "exec-opts": ["native.cgroupdriver=systemd"]
    ...
}
 # 刷新配置
systemctl daemon-reload
# 重启docker
systemctl restart docker
# 重启kubelet
systemctl restart kubelet
  
       
     
  
     在master节点运行
 # 注意，其中--image-repository指定初始化下载的镜像，--v=6开启详细日志打印
$ kubeadm init \
--image-repository=registry.aliyuncs.com/google_containers \
--apiserver-advertise-address=192.168.234.129 \
--kubernetes-version v1.23.0 \
--service-cidr=192.166.0.0/16 \
--pod-network-cidr=192.167.0.0/16 \
--v=6

# --image-repository镜像加速
# --apiserver-advertise-address 直接使用当前master主机地址
# --kubernetes-version k8s版本，可以不指定，缺省情况会用最新的
# --service-cidr k8s中的service网络地址，不可与主机，pod网络地址重复
# --pod-network-cidr pod网络地址，不可与主机，service网络地址重读，与后面的Calico相关
# --v,日志等级，5级以上会打印更详细的日志，方便差错
 #以下输出表示初始化完成

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 192.168.234.129:6443 --token pptc23.2kyz3xmu5ehv4j3p \
  --discovery-token-ca-cert-hash sha256:fe9b576d3a52502ef46d09010cfc14cb6dfc4fdb885873ebf09cf8be7950f5b3
  
     配置kubectl
 mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
  
     安装Calico(CNI)
 # 直接使用Calico远程配置文件，也可将文件上传至服务器安装
$ curl https://docs.projectcalico.org/manifests/calico.yaml -O
$ kubectl apply -f calico.yaml
  
     node节点加入集群
 $ kubeadm join 192.168.234.129:6443 --token pptc23.2kyz3xmu5ehv4j3p \
  --discovery-token-ca-cert-hash sha256:fe9b576d3a52502ef46d09010cfc14cb6dfc4fdb885873ebf09cf8be7950f5b3
 # 表示加入成功
[preflight] Running pre-flight checks
[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'
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Starting the kubelet
[kubelet-start] Waiting for the kubelet to perform the TLS Bootstrap...

This node has joined the cluster:
* Certificate signing request was sent to apiserver and a response was received.
* The Kubelet was informed of the new secure connection details.

Run 'kubectl get nodes' on the control-plane to see this node join the cluster.
  
     配置节点角色
 $ kubectl get nodes 
NAME         STATUS   ROLES                  AGE     VERSION
k8s-master   Ready    control-plane,master   23m     v1.23.0
k8s-node1    Ready                     9m43s   v1.23.0
k8s-node2    Ready                     7m41s   v1.23.0
# 发现节点ROLES是
$ kubectl label nodes k8s-node1 node-role.kubernetes.io/node=
$ kubectl label nodes k8s-node2 node-role.kubernetes.io/node=
# 再次运行
$ kubectl get nodes
NAME         STATUS   ROLES                  AGE   VERSION
k8s-master   Ready    control-plane,master   25m   v1.23.0
k8s-node1    Ready    node                   12m   v1.23.0
k8s-node2    Ready    node                   10m   v1.23.0
  
   
  
   验证集群是否正常
 apiVersion: apps/v1
kind: Deployment
metadata:
  name: app-demo
  labels:
    app: app-demo
spec:
  replicas: 3
  template:
    metadata:
      name: app-demo
      labels:
        app: nginx-demo
    spec:
      containers:
        - name: nginx-demo
          image: nginx:stable-alpine
          imagePullPolicy: IfNotPresent
          ports:
            - containerPort: 80
      restartPolicy: Always
  selector:
    matchLabels:
      app: nginx-demo
---
apiVersion: v1
kind: Service
metadata:
  name: nginx-svr
spec:
  selector:
    app: nginx-demo
  ports:
    - protocol: TCP
      port: 10080
      targetPort: 80
      nodePort: 30080
  type: NodePort
---
apiVersion: v1
kind: Namespace
metadata:
  name: ns-nginx
  labels:
    name: ns-nginx
 $ kubectl apply -f .
$ kubectl get pods -o wide
# 已经被分别部署到两个节点上，也能看到pod IP段是正常的
NAME                        READY   STATUS    RESTARTS   AGE     IP                NODE        NOMINATED NODE   READINESS GATES
app-demo-6ffbbc8f85-96fwg   1/1     Running   0          2m44s   192.167.36.65     k8s-node1              
app-demo-6ffbbc8f85-pw4fw   1/1     Running   0          2m44s   192.167.169.130   k8s-node2              
app-demo-6ffbbc8f85-rc2pb   1/1     Running   0          2m44s   192.167.169.129   k8s-node2              
 浏览器分别访问三台主机，均可出现nginx表示集群部署成功

角色	IP
master	192.168.234.129
node1	192.168.234.130
node2	192.168.234.131

Centos7在线安装k8s

系统与版本

安装kubeadm

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