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如何使用 kubeadm 安装 Kubernetes?

本文讲解如何使用kubeadm安装。

作者|阿文

责编|郭芮

kubeadm能帮助您建立一个小型的符合最佳实践的Kubernetes集群。它可以运行在不同类型的机器上,例如笔记本、服务器和树莓派等。对于kubernetes不熟悉的新用户可以使用kubeadm快速的开始试用kubernetes。

准备三台机

192.168.10.89master

192.168.10.7node1

192.168.10.8node2

他们的配置是8核8G。

安装Docker

1.安装docker

yum-yinstalldocker

sudotee/etc/docker/'EOF'

{

"registry-mirrors":[""]

}

EOF

sudosystemctldaemon-reload

sudosystemctlrestartdocker

安装kubeadm

1.添加kubernetes源

catEOF/etc//

[kubernetes]

name=Kubernetes

baseurl=

enabled=1

gpgcheck=0

repo_gpgcheck=0

gpgkey=

EOF

2.执行如下命令安装kubeletkubeadmkubectl

yuminstall-ykubeletkubeadmkubectl--disableexcludes=kubernetes

systemctlenablekubeletsystemctlstartkubelet

3.执行查看kubeadm的images

kubeadmconfigimageslist

可以看到如下信息:

W081509:36:13.25161144413:98]couldnotfetchaKubernetesversionfromtheinternet:unabletogetURL"":Get()

W081509:36:13.25173044413:99]fallingbacktothelocalclientversion:

/kube-apiserver:

/kube-controller-manager:

/kube-scheduler:

/kube-proxy:

/pause:3.1

/etcd:3.3.10

/coredns:1.3.1

4.由于被墙,所以,我们可以使用阿里云的源来安装,将如下信息保存为k8s_images_后运行脚本下载镜像。

images=(

kube-apiserver:

kube-controller-manager:

kube-scheduler:

kube-proxy:

pause:3.1

etcd:3.3.10

coredns:1.3.1

)

forimageNamein${images[@]};do

/google_containers/$imageName

/google_containers/$/$imageName

/google_containers/$imageName

done

5.然后执行如下命令安装kubeadm。

kubeadminit--kubernetes-version==10.244.0.0/16--service-cidr=10.96.0.0/12

安装完毕会提示:

YourKubernetescontrol-planehasinitializedsuccessfully!

Tostartusingyourcluster,youneedtorunthefollowingasaregularuser:

mkdir-p$HOME/.kube

sudocp-i/etc/kubernetes/$HOME/.kube/config

sudochown$(id-u):$(id-g)$HOME/.kube/config

Youshouldnowdeployapodnetworktothecluster.

Run"kubectlapply-f[podnetwork].yaml"withoneoftheoptionslistedat:

Thenyoucanjoinanynumberofworkernodesbyrunningthefollowingoneachasroot:

:6443--\

--discovery-token-ca-cert-hashsha256:c8c4d08806ec22851c0eaa4e41962576b19d372e92f638a88e89f166e2a2c4af

注意这里的——

:6443--\

--discovery-token-ca-cert-hashsha256:c8c4d08806ec22851c0eaa4e41962576b19d372e92f638a88e89f166e2a2c4af

信息我们保存下来,稍后会在node节点使用到,我们根据提示执行:

mkdir-p$HOME/.kube

sudocp-i/etc/kubernetes/$HOME/.kube/config

sudochown$(id-u):$(id-g)$HOME/.kube/config

Kubernetes集群默认需要加密方式访问。所以,这几条命令,就是将刚刚部署生成的Kubernetes集群的安全配置文件,保存到当前用户的.kube目录下,kubectl默认会使用这个目录下的授权信息访问Kubernetes集群。

然后添加网络插件,否则CoreDNS、kube-controller-manager等依赖于网络的Pod都处于Ping状态,会调度失败。如下所示:

kubectlgetpods--all-namespaces

NAMESPACENAMEREADYSTATUSRESTARTSAGE

kube-systemcoredns-5c98db65d4-5jntb1/1Running026m

kube-systemcoredns-5c98db65d4-db2xj1/1Running026m

/1Running025m

/1Running025m

/1Running025m

kube-systemkube-flannel-ds-amd64-9tscr1/1Running016m

kube-systemkube-flannel-ds-amd64-pc4kp1/1Running024m

kube-systemkube-flannel-ds-amd64-tts291/1Running017m

kube-systemkube-proxy-64f8t1/1Running016m

kube-systemkube-proxy-6qwv61/1Running026m

kube-systemkube-proxy-js7bb1/1Running017m

/1Running025m

Node节点配置

接下来我们分别配置2台node节点,以下配置分别在2台node上执行。

1.添加kubernetes源

catEOF/etc//

[kubernetes]

name=Kubernetes

baseurl=

enabled=1

gpgcheck=0

repo_gpgcheck=0

gpgkey=

EOF

2.执行

yuminstall-ykubeletkubeadmkubectl--disableexcludes=kubernetes

systemctlenablekubeletsystemctlstartkubelet

3.安装node节点所需的组件,由于node节点不需要api-server和controller-manager、scheduler、etcd,我们只需要安装kube-proxy、pause、coredns即可。

images=(

kube-proxy:

pause:3.1

coredns:1.3.1

)

forimageNamein${images[@]};do

/google_containers/$imageName

/google_containers/$/$imageName

/google_containers/$imageName

done

然后执行master节点我们执行kubeadminit后得到join信息将node节点加入到集群:

:6443--:00eb62a2a6020f94132e3fe1ab721349bbcd3e9b94da9654cfe15f2985ebd711

然后在master执行如下命令查看nodes信息:

/config

apiVersion:v1

clusters:

-cluster:

certificate-authority-data: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

server:

name:kubernetes

……

当Client使用该config文件启动kubelet后,他将访问Master节点的6443端口获得数据(Master6443端口是处于LISTEN状态的),而非localhost:8080端口(因为Node节点无法找到该config文件)。

我们也可以把Client客户端放在其他主机中,甚至Node节点。只要将该config文件按照系统提示方式添加到Client客户端中即可。我们使用scp命令将文件发送至目标主机:

/node1:/root

/node2:/root

即可。

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