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Centos7系統使用kubeadm方式安裝k8s叢集v1.26.1版本kubeadm方式安裝k8s叢集

kubeadm方式安裝k8s叢集

一、準備機器

主機 說明
192.168.0.11 master節點,能連外網,官網最低要求2核2G
192.168.0.12 node1節點,能連外網,官網最低要求2核2G
192.168.0.13 node2節點,能連外網,官網最低要求2核2G

二、伺服器環境配置

2.1 關閉防火牆(所有節點)

關閉防火牆并設定開機不啟動

systemctl stop firewalld
systemctl disable firewalld
           

2.2 禁用selinux(所有節點)

#修改/etc/selinux/config檔案中的SELINUX=disabled
vim /etc/selinux/config
           

2.3 關閉swap分區(所有節點)

修改後重新開機伺服器生效

vim /etc/fstab						#永久禁用swap,删除或注釋掉/etc/fstab裡的swap裝置的挂載指令即可
#/dev/mapper/centos-swap swap                    swap    defaults        0 0
           

2.4 Centos7核心更新(所有節點)

CentOS 7.x 系統自帶的 3.10.x 核心存在一些 Bugs,導緻運作的 Docker、Kubernetes 不穩定

參考:更新centos系統核心

2.5 設定主機名(所有節點)

cat >> /etc/hosts <<EOF
192.168.0.11 master
192.168.0.12 worker01
192.168.0.13 worker02
EOF
           

2.6 時間同步(所有節點)

yum -y install ntp
systemctl start ntpd
systemctl enable ntpd
           

三、安裝docker(所有節點)

按照此方法安裝docker:centos安裝docker-ce

配置docker

#registry-mirrors是配置docker鏡像源
#exec-opts是配置Cgroup Driver為systemd,因為k8s使用的是systemd
cat <<EOF > /etc/docker/daemon.json
{
    "registry-mirrors": [
        "http://hub-mirror.c.163.com",
        "https://docker.mirrors.ustc.edu.cn",
        "https://registry.docker-cn.com"
    ],
    "exec-opts": ["native.cgroupdriver=systemd"]
}
EOF

#重新開機docker後檢視是否生效
systemctl restart docker
docker info | grep -i "Cgroup Driver"
           

四、安裝cri-dockerd(所有節點)

#從https://github.com/Mirantis/cri-dockerd/releases中下載下傳最新的rpm包,手動下載下傳後上傳到伺服器裡
rpm -ivh cri-dockerd-0.3.1-3.el7.x86_64.rpm

#修改/usr/lib/systemd/system/cri-docker.service檔案中的ExecStart配置
vim /usr/lib/systemd/system/cri-docker.service
ExecStart=/usr/bin/cri-dockerd --network-plugin=cni --pod-infra-container-image=registry.aliyuncs.com/google_containers/pause:3.7

systemctl daemon-reload
systemctl enable --now cri-docker
           

五、配置kubernetes的阿裡雲yum源(所有節點)

baseurl位址末尾的x86_64值需要根據系統修改,輸入 uname -m 以檢視該值。 例如,x86_64 的 baseurl URL 可以是:https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64

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
           

六、yum安裝kubeadm、kubelet、kubectl(所有節點)

在3台虛拟機上都執行安裝kubeadm、kubelet、kubectl(kubeadm和kubectl都是工具,kubelet才是系統服務)

#删除之前的
yum -y remove kubelet kubeadm kubectl

#檢視yum可擷取的kubeadm版本,這裡安裝1.26.1版本,不指定版本的話預設安裝最新版本
yum list --showduplicates | grep  kubeadm
#安裝kubeadm、kubelet、kubectl
yum -y install kubelet-1.26.1 kubeadm-1.26.1 kubectl-1.26.1
#設定kubelet開機自啟(先不用啟動,也起不了,後面kubeadm init初始化master時會自動拉起kubelet)
systemctl enable kubelet
           

七、初始化master節點的控制台(master節點)

執行下面指令可能會報錯,按照此Kubernetes常見報錯進行相應修改

# kubeadm init --help可以檢視指令的具體參數用法

#在master節點執行初始化(node節點不用執行)
#apiserver-advertise-address  指定apiserver的IP,即master節點的IP
#image-repository  設定鏡像倉庫為國内的阿裡雲鏡像倉庫
#kubernetes-version  設定k8s的版本,跟步驟三的kubeadm版本一緻
#service-cidr  這是設定node節點的網絡的,暫時這樣設定
#pod-network-cidr  這是設定node節點的網絡的,暫時這樣設定
#cri-socket  設定cri使用cri-dockerd

kubeadm init \
--apiserver-advertise-address=192.168.0.11 \
--image-repository registry.aliyuncs.com/google_containers \
--kubernetes-version v1.26.1 \
--service-cidr=10.96.0.0/12 \
--pod-network-cidr=10.244.0.0/16 \
--cri-socket unix:///var/run/cri-dockerd.sock \
--ignore-preflight-errors=all
           

如果上面kubeadm init指令有錯誤,執行下面指令重置kubeadm及無用的鏡像

#重置Kubeadm
kubeadm reset -f

#删除docker無用的鏡像容器
docker system prune -f
           

上面執行後出現下面結果表示成功

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 192.168.0.11:6443 --token xw8o4d.ly5o9kxgbodtrykw \
        --discovery-token-ca-cert-hash sha256:2fbb2be8829dd90f789b13269f2ef4d8de6a39bc568c61e3a6a00ea3c95efd94
           

根據上面結果在master節點執行相應指令(直接複制上面提示的指令即可)

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
export KUBECONFIG=/etc/kubernetes/admin.conf
           

八、将node節點加入k8s叢集

#指令最後加上cri-socket指定使用cri-dockerd
kubeadm join 192.168.0.11:6443 --token xw8o4d.ly5o9kxgbodtrykw \
        --discovery-token-ca-cert-hash sha256:2fbb2be8829dd90f789b13269f2ef4d8de6a39bc568c61e3a6a00ea3c95efd94 \
        --cri-socket unix:///var/run/cri-dockerd.sock
           

上面指令報錯後根據報錯内容進行相應修改即可,例如下面報錯資訊

[preflight] Running pre-flight checks
        [WARNING Swap]: swap is enabled; production deployments should disable swap unless testing the NodeSwap feature gate of the kubelet
error execution phase preflight: [preflight] Some fatal errors occurred:
        [ERROR FileAvailable--etc-kubernetes-kubelet.conf]: /etc/kubernetes/kubelet.conf already exists
        [ERROR Port-10250]: Port 10250 is in use
        [ERROR FileAvailable--etc-kubernetes-pki-ca.crt]: /etc/kubernetes/pki/ca.crt already exists
[preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...`
To see the stack trace of this error execute with --v=5 or higher
           

删除已有配置檔案并重新開機kubelet即可

kubeadm reset --cri-socket unix:///var/run/cri-dockerd.sock


rm -f /etc/kubernetes/kubelet.conf
rm -f /etc/kubernetes/pki/ca.crt
systemctl stop kubelet
           

九、在master節點配置pod網絡建立

執行kubectl get nodes後檢視發現都是NotReady,需要配置CNI網絡插件

[[email protected] ~]# kubectl get nodes
NAME       STATUS     ROLES           AGE   VERSION
master     NotReady   control-plane   58m   v1.26.1
worker01   NotReady   <none>          37m   v1.26.1
worker02   NotReady   <none>          25m   v1.26.1
           
#在master節點配置pod網絡建立
#node節點加入k8s叢集後,在master上執行kubectl get nodes發現狀态是NotReady,因為還沒有部署CNI網絡插件,其實在步驟四初始化
#完成master節點的時候k8s已經叫我們去配置pod網絡了。在k8s系統上Pod網絡的實作依賴于第三方插件進行,這類插件有近數十種之多,較為
#著名的有flannel、calico、canal和kube-router等,簡單易用的實作是為CoreOS提供的flannel項目。

#執行下面這條指令線上配置pod網絡,因為是國外網站,是以可能報錯,測試去http://ip.tool.chinaz.com/網站查到
#域名raw.githubusercontent.com對應的IP,把域名解析配置到/etc/hosts檔案,然後執行線上配置pod網絡,多嘗試幾次即可成功。
[[email protected] ~]# kubectl apply -f https://raw.githubusercontent.com/flannel-io/flannel/master/Documentation/kube-flannel.yml					
Warning: policy/v1beta1 PodSecurityPolicy is deprecated in v1.21+, unavailable in v1.25+
podsecuritypolicy.policy/psp.flannel.unprivileged created
clusterrole.rbac.authorization.k8s.io/flannel created
clusterrolebinding.rbac.authorization.k8s.io/flannel created
serviceaccount/flannel created
configmap/kube-flannel-cfg created
daemonset.apps/kube-flannel-ds created
[[email protected] ~]# kubectl get pods -n kube-system						#檢視pod狀态
NAME                             READY   STATUS     RESTARTS   AGE
coredns-7f6cbbb7b8-bm2gl         0/1     Pending    0          86m
coredns-7f6cbbb7b8-frq8l         0/1     Pending    0          86m
etcd-master                      1/1     Running    1          87m
kube-apiserver-master            1/1     Running    1          87m
kube-controller-manager-master   1/1     Running    1          87m
kube-flannel-ds-5rwkt            0/1     Init:1/2   0          2m13s
kube-flannel-ds-9fqkl            1/1     Running    0          2m13s
kube-flannel-ds-bvgh4            1/1     Running    0          2m13s
kube-proxy-8vmqg                 1/1     Running    0          59m
kube-proxy-ll9hw                 1/1     Running    0          86m
kube-proxy-zndg7                 1/1     Running    0          59m
kube-scheduler-master            1/1     Running    1          87m
# 重新開機伺服器後擷取
[[email protected] ~]# kubectl get nodes										#pod網絡已經配置完成,狀态已經是Ready
NAME       STATUS     ROLES           AGE   VERSION
master     Ready      control-plane   58m   v1.26.1
worker01   Ready      <none>          37m   v1.26.1
worker02   Ready      <none>          25m   v1.26.1
           

十、測試k8s叢集

在k8s中建立一個pod,驗證是否正常運作

[[email protected] ~]# kubectl create deployment httpd --image=httpd					#建立一個httpd服務測試
deployment.apps/httpd created
[[email protected] ~]# kubectl expose deployment httpd --port=80 --type=NodePort		#端口就寫80,如果你寫其他的可能防火牆攔截了
service/httpd exposed
[[email protected] ~]# kubectl get pod,svc											#對外暴露端口
NAME                         READY   STATUS    RESTARTS   AGE
pod/httpd-757fb56c8d-w42l5   1/1     Running   0          39s

NAME                 TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)          AGE
service/httpd        NodePort    10.102.83.215   <none>        80:30176/TCP     26s			#30176端口就是對外映射的端口
service/kubernetes   ClusterIP   10.96.0.1       <none>        443/TCP          112m
[[email protected] ~]# 
#作為初學者,以上指令先不用糾結,端口就寫80即可,如果你寫其他的端口可能防火牆攔截了,網頁就通路不了

           

網頁測試通路,使用master節點的IP或者node節點的IP都可以通路,端口就是30176,如下所示,這就說明我們k8s已經部署完成,網絡ok。

Centos7系統使用kubeadm方式安裝k8s叢集v1.26.1版本kubeadm方式安裝k8s叢集

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