k8s入坑之路（4）kubeadm安装kubernetes集群

清疚 2024-04-01 03:16 57阅读 0赞

> 参考链接：[安装配置k8s-使用kubeadm的方式配置k8s集群，完全版。][k8s-_kubeadm_k8s]

系统版本信息和软件版本信息

# 系统信息
    内核版本： Linux 3.10.0-1160.el7.x86_64
    系统版本： CentOS Linux release 7.9.2009 (Core)
    
    # 软件信息
    docker 版本： docker-ce-18.06.1.ce-3.el7
    kubelet版本： kubelet-1.18.0 
    kubeadm版本： kubeadm-1.18.0 
    kubectl版本： kubectl-1.18.0

kubeadm是官方社区推出的一个用于快速部署kubernetes集群的工具。

这个工具能通过两条指令完成一个kubernetes集群的部署：

# 创建一个 Master 节点
    $ kubeadm init
    
    # 将一个 Node 节点加入到当前集群中
    $ kubeadm join <Master节点的IP和端口 >

## 1. 安装要求 ##

在开始之前，部署Kubernetes集群机器需要满足以下几个条件：

一台或多台机器，操作系统 CentOS7.x-86\_x64  
硬件配置：2GB或更多RAM，2个CPU或更多CPU，硬盘30GB或更多  
可以访问外网，需要拉取镜像，如果服务器不能上网，需要提前下载镜像并导入节点  
禁止swap分区

## 2. 准备环境(每台机器机器上都要操作) ##

<table> 
 <thead> 
  <tr> 
   <th>角色</th> 
   <th>IP</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>master</td> 
   <td>192.168.1.100</td> 
  </tr> 
  <tr> 
   <td>node1</td> 
   <td>192.168.1.103</td> 
  </tr> 
  <tr> 
   <td>node2</td> 
   <td>192.168.1.104</td> 
  </tr> 
 </tbody> 
</table>

准备环境

# 关闭防火墙
    systemctl stop firewalld
    systemctl disable firewalld
    
    # 关闭selinux
    sed -i 's/enforcing/disabled/' /etc/selinux/config  
    setenforce 0  
    
    # 关闭swap
    swapoff -a  
    sed -ri 's/.*swap.*/#&/' /etc/fstab    
    
    # 根据规划设置主机名(各机器安装自己角色执行)
    hostnamectl set-hostname <hostname> 
    hostnamectl set-hostname  k8s-master1
    hostnamectl set-hostname  k8s-node1 
    hostnamectl set-hostname  k8s-node2 
    
    # 在master添加hosts(本步骤仅在master机器上操作)
    cat >> /etc/hosts << EOF
    192.168.1.100 k8s-master1
    192.168.1.103 k8s-node1 
    192.168.1.104 k8s-node2
    EOF
    
    # 将桥接的IPv4流量传递到iptables的链
    cat > /etc/sysctl.d/k8s.conf << EOF
    net.bridge.bridge-nf-call-ip6tables = 1
    net.bridge.bridge-nf-call-iptables = 1
    EOF
    sysctl --system  # 生效
    
    # 时间同步
    yum install ntpdate -y
    ntpdate time.windows.com

## 3. 所有节点安装Docker/kubeadm/kubelet(所有结点即所有的master和node服务器) ##

Kubernetes默认CRI(容器运行时)为Docker，因此先安装Docker。

### 3.1 安装Docker ###

安装Docker

#添加阿里云的docker源并yum安装docker
    $ wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo
    $ yum -y install docker-ce-18.06.1.ce-3.el7
    $ systemctl enable docker && systemctl start docker  (docker设置成开机启动&&启动docker)
    $ docker --version
    Docker version 18.06.1-ce, build e68fc7a
    #设置docker镜像加速(连阿里的镜像)
    $ cat > /etc/docker/daemon.json << EOF
    {
      "registry-mirrors": ["https://b9pmyelo.mirror.aliyuncs.com"]
    }
    EOF
    # 重启docker
    systemctl restart docker

### 3.2 添加Kubernetes阿里云YUM软件源 ###

添加阿里云YUM软件源(所有结点即所有的master和node服务器，以下没特别说明，就是全部的节点都要进行的操作)

添加Kubernetes阿里云YUM软件源

# 所有节点添加Kubernetes阿里云YUM软件源
    $ cat > /etc/yum.repos.d/kubernetes.repo << EOF
    [kubernetes]
    name=Kubernetes
    baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
    enabled=1
    gpgcheck=0
    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
    EOF

### 3.3 所有节点安装kubeadm，kubelet和kubectl ###

由于版本更新频繁，这里指定版本号部署：

所有节点安装kubeadm，kubelet和kubectl

# 所有节点安装kubeadm，kubelet和kubectl 
    $ yum install -y kubelet-1.18.0 kubeadm-1.18.0 kubectl-1.18.0
    $ systemctl enable kubelet(开机启动)

## 4. 部署Kubernetes Master(muster中执行) ##

在192.168.1.100(Master)执行。

部署Kubernetes Master(muster中执行)

$ kubeadm init 
      --apiserver-advertise-address=192.168.1.100   		(当前节点的ip，即自己muster的ip)
      --image-repository registry.aliyuncs.com/google_containers 	( k8s的镜像，用阿里的，因为官方的在国外，可能无法访问)
      --kubernetes-version v1.18.0 					( 指定当前版本)
      --service-cidr=10.96.0.0/12 					( 随便写，和当前的ip不冲突即可)
      --pod-network-cidr=10.244.0.0/16				(这六行时一条命令，在一条命令中执行)
    
    # 输出 
    ...
    [kubelet-finalize] Updating "/etc/kubernetes/kubelet.conf" to point to a rotatable kubelet client certificate and key
    [addons] Applied essential addon: CoreDNS
    [addons] Applied essential addon: kube-proxy
    
    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
    
    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 192.168.1.100:6443 --token q3esl2.uqdglp5rh3jyp30j \
        --discovery-token-ca-cert-hash sha256:28fad121ff6211266c6b658d27bb0d5b0ceb638eaba1f38898db42683d79c2df

由于默认拉取镜像地址k8s.gcr.io国内无法访问，这里指定阿里云镜像仓库地址。

使用kubectl工具：

创建admin.conf文件

mkdir -p $HOME/.kube
    sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
    sudo chown $(id -u):$(id -g) $HOME/.kube/config
    $ kubectl get nodes	(上面几行为一句话，这句话为查询master和node的状态)
    
    # 输出：
    [root@localhost ~]# kubectl get nodes
    NAME             STATUS     ROLES    AGE   VERSION
    k8s-master1cat   NotReady   master   89s   v1.18.0

## 5. 加入Kubernetes Node(在node中执行，吧node加到master中) ##

在192.168.1.103/104(在Node)执行。

向集群添加新节点，执行在kubeadm init输出的kubeadm join命令：(部署完kubeadm会出现下面一段话，然后直接复制粘贴都node节点中执行)

加入Kubernetes Node

$ kubeadm join 192.168.1.100:6443 --token q3esl2.uqdglp5rh3jyp30j \
        --discovery-token-ca-cert-hash sha256:28fad121ff6211266c6b658d27bb0d5b0ceb638eaba1f38898db42683d79c2df
    
    # 输出：
    [root@localhost ~]# kubeadm join 192.168.1.100:6443 --token q3esl2.uqdglp5rh3jyp30j \
    >     --discovery-token-ca-cert-hash sha256:28fad121ff6211266c6b658d27bb0d5b0ceb638eaba1f38898db42683d79c2df
    W0614 15:56:03.534220    3290 join.go:346] [preflight] WARNING: JoinControlPane.controlPlane settings will be ignored when control-plane flag is not set.
    [preflight] Running pre-flight checks
    	[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/
    [preflight] Reading configuration from the cluster...
    [preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml'
    [kubelet-start] Downloading configuration for the kubelet from the "kubelet-config-1.18" ConfigMap in the kube-system namespace
    [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.

默认token有效期为24小时，当过期之后，该token就不可用了。这时就需要重新创建token，操作如下：

重新创建token

kubeadm token create --print-join-command

## 6. 部署CNI网络插件(master和node都要配置) ##

部署CNI网络插件(master和node都要配置)

# 部署CNI网络插件(master和node都要配置)
    wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
    
    # 默认镜像地址无法访问，sed命令修改为docker hub镜像仓库。
    kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
    
    # 看组件有没有运行起来
    kubectl get pods -n kube-system(这个命令来看组件有没有运行起来)
    NAME                          READY   STATUS    RESTARTS   AGE
    kube-flannel-ds-amd64-2pc95   1/1     Running   0          72s

## 7. 测试kubernetes集群 ##

在Kubernetes集群中创建一个pod，验证是否正常运行：

测试kubernetes集群

#(拉取nginx镜像，创建一个nginx的pod)
    $ kubectl create deployment nginx --image=nginx  (拉取nginx镜像，创建一个nginx的pod)
    
    #(对外暴漏端口)
    $ kubectl expose deployment nginx --port=80 --type=NodePort(对外暴漏端口)
    
    # 查看暴漏端口
    $ kubectl get pod,svc	
    
    #输出
    [root@localhost ~]# kubectl get pod,svc
    NAME                        READY   STATUS              RESTARTS   AGE
    pod/nginx-f89759699-fnl78   0/1     ContainerCreating   0          86s
    
    NAME                 TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE
    service/kubernetes   ClusterIP   10.96.0.1        <none>        443/TCP        17m
    service/nginx        NodePort    10.100.197.109   <none>        80:30219/TCP   77s

访问地址：[http://NodeIP][http_NodeIP]:Port![3a24baf3539b1a4688b8f0122bd5c494.png][]

[k8s-_kubeadm_k8s]: https://blog.csdn.net/qq_31897241/article/details/122691831?spm=1001.2101.3001.6650.16&utm_medium=distribute.pc_relevant.none-task-blog-2%7Edefault%7EBlogCommendFromBaidu%7Edefault-16-122691831-blog-123359523.pc_relevant_default&depth_1-utm_source=distribute.pc_relevant.none-task-blog-2%7Edefault%7EBlogCommendFromBaidu%7Edefault-16-122691831-blog-123359523.pc_relevant_default&utm_relevant_index=20
[http_NodeIP]: http://NodeIP
[3a24baf3539b1a4688b8f0122bd5c494.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/01/3c56f3b5cb284ca783d5f3d298521833.png