使用kubeadm工具箱创建Kubernetes集群

安装kubeadm

环境准备：CentOS 7 16G Memory 16 CPUs （笔者服务器配置）

每个节点的唯一主机名，MAC地址和product_uuid

必须禁用swap为了使kubelet正常工作

swapoff

# 修改/ets/fatab,注释swap的挂载配置/重要

验证每个节点的MAC地址和product_uuid是唯一的

# 可以使用命令下面检查product_uuid：

sudo cat /sys/class/dmi/id/product_uuid

检查网络适配器

如果您有多个网络适配器，并且您的Kubernetes组件在默认路由上无法访问，我们建议您添加IP路由，以便Kubernetes集群地址通过适当的适配器

检查所需端口

Master node(s)

Worker node(s)

默认的端口范围:https://kubernetes.io/docs/concepts/services-networking/service/

安装Docker 参考：https://www.linuxidc.com/Linux/2018-03/151478.htm  Docker官方安装：https://docs.docker.com/engine/installation/

yum install -y docker systemctl enable docker && systemctl start docker # 不建议使用官网的docker-ce版本、支持性不是很好、使用epel源支持的docker即可 [root@aniu-k8s ~]# docker version Client: Version:        1.12.6 API version:    1.24 Package version: docker-1.12.6-68.gitec8512b.el7.centos.x86_64 Go version:      go1.8.3 Git commit:      ec8512b/1.12.6 Built:          Mon Dec 11 16:08:42 2017 OS/Arch:        linux/amd64

Server: Version:        1.12.6 API version:    1.24 Package version: docker-1.12.6-68.gitec8512b.el7.centos.x86_64 Go version:      go1.8.3 Git commit:      ec8512b/1.12.6 Built:          Mon Dec 11 16:08:42 2017 OS/Arch:        linux/amd64

在每台机器上安装Docker。建议使用v1.12版本，但v1.11，v1.13和17.03版本也是可以的。版本17.06+可能有效，但尚未经过Kubernetes节点团队的测试和验证。

请以root身份根据您的操作系统执行以下命令。通过SSH连接到每个主机后，您可以通过执行sudo -i成为root用户 确保kubelet使用的cgroup驱动程序与Docker使用的相同。为了确保兼容性，您可以更新Docker，如下所示： cat << EOF > /etc/docker/daemon.json {   "exec-opts": ["native.cgroupdriver=systemd"] } EOF # 这里使用官网配置启动docker报错/启用使用默认配置

安装kubeadm, kubelet and kubectl kubeadm：引导群集的命令 kubelet：运行在集群中所有机器上的组件，并执行诸如启动pods和容器的组件。

kubectl: 与集群交互

配置官方kubernetes源：

cat <<EOF > /etc/yum.repos.d/kubernetes.repo [kubernetes] name=Kubernetes baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64 enabled=1 gpgcheck=1 repo_gpgcheck=1 gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg EOF

配置国内kubernetes源 # cat > /etc/yum.repo.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 EOF

禁用SELinux并关闭防火墙 sed -i 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/selinux/config # 需重启 setenforce 0 #关闭防火墙 systemctl stop firewalld && systemctl disable firewalld

RHEL / CentOS 7上的某些用户报告了由于iptables被绕过而导致流量被错误路由的问题。应该确保net.bridge.bridge-nf-call-iptables的sysctl配置中被设置为1，例如 cat <<EOF >  /etc/sysctl.d/k8s.conf net.bridge.bridge-nf-call-ip6tables = 1 net.bridge.bridge-nf-call-iptables = 1 EOF sysctl --system

安装kubelet kubeadm kubectl [root@aniu-k8s ~]# yum install -y kubelet kubeadm kubectl Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile  * base: mirrors.163.com  * epel: mirrors.tongji.edu.cn  *  extras: mirrors.163.com  * updates: mirrors.163.com Package kubelet-1.9.2-0.x86_64 already installed and latest version Package kubeadm-1.9.2-0.x86_64 already installed and latest version Package kubectl-1.9.2-0.x86_64 already installed and latest version Nothing to do

# systemctl enable kubelet && systemctl start kubelet

初始化kubeadm，否则启动kubelet报证书错误 [root@aniu-k8s ~]# kubeadm init --kubernetes-version=v1.9.2 [init] Using Kubernetes version: v1.9.2 [init] Using Authorization modes: [Node RBAC] [preflight] Running pre-flight checks.         [WARNING FileExisting-crictl]: crictl not found in system path [preflight] Starting the kubelet service [certificates] Generated ca certificate and key. [certificates] Generated apiserver certificate and key. [certificates] apiserver serving cert is signed for DNS names [aniu-k8s kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 192.168.10.10] [certificates] Generated apiserver-kubelet-client certificate and key. [certificates] Generated sa key and public key. [certificates] Generated front-proxy-ca certificate and key. [certificates] Generated front-proxy-client certificate and key. [certificates] Valid certificates and keys now exist in "/etc/kubernetes/pki" [kubeconfig] Wrote KubeConfig file to disk: "admin.conf" [kubeconfig] Wrote KubeConfig file to disk: "kubelet.conf" [kubeconfig] Wrote KubeConfig file to disk: "controller-manager.conf" [kubeconfig] Wrote KubeConfig file to disk: "scheduler.conf" [controlplane] Wrote Static Pod manifest for component kube-apiserver to "/etc/kubernetes/manifests/kube-apiserver.yaml" [controlplane] Wrote Static Pod manifest for component kube-controller-manager to "/etc/kubernetes/manifests/kube-controller-manager.yaml" [controlplane] Wrote Static Pod manifest for component kube-scheduler to "/etc/kubernetes/manifests/kube-scheduler.yaml" [etcd] Wrote Static Pod manifest for a local etcd instance to "/etc/kubernetes/manifests/etcd.yaml" [init] Waiting for the kubelet to boot up the control plane as Static Pods from directory "/etc/kubernetes/manifests". [init] This might take a minute or longer if the control plane images have to be pulled. [apiclient] All control plane components are healthy after 75.502276 seconds [uploadconfig] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace [markmaster] Will mark node aniu-k8s as master by adding a label and a taint [markmaster] Master aniu-k8s tainted and labelled with key/value: node-role.kubernetes.io/master="" [bootstraptoken] Using token: d9b013.26c2f690632cbef9 [bootstraptoken] Configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials [bootstraptoken] Configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token [bootstraptoken] Configured RBAC rules to allow certificate rotation for all node client certificates in the cluster [bootstraptoken] Creating the "cluster-info" ConfigMap in the "kube-public" namespace [addons] Applied essential addon: kube-dns [addons] Applied essential addon: kube-proxy

Your Kubernetes master 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/

You can now join any number of machines by running the following on each node as root:

  kubeadm join --token d9b013.26c2f690632cbef9 192.168.10.10:6443 --discovery-token-ca-cert-hash sha256:887a2ea3fccca1dec2caa12ad2e54f5baf806f29becf548a3b098ee3a869b518

使用kubeadm创建群集

参考：https://kubernetes.io/docs/setup/independent/create-cluster-kubeadm/

kubeadm是一个工具包，可帮助您以简单，合理安全和可扩展的方式引导最佳实践Kubernetes群集。它还支持为您管理Bootstrap令牌并升级/降级群集。

它在设计上并不为您安装网络解决方案，这意味着您必须使用kubectl apply自行安装第三方符合CNI的网络解决方案 初始化master [root@aniu-k8s ~]# kubeadm init --kubernetes-version=v1.9.21

要让kubectl为非root用户工作，您可能需要运行以下命令（这也是kubeadm init输出的一部分）：

mkdir -p $HOME/.kube

sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config

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

查看集群状态 [root@aniu-k8s ~]# kubectl get cs NAME                STATUS    MESSAGE              ERROR controller-manager  Healthy  ok                  scheduler            Healthy  ok                  etcd-0              Healthy  {"health": "true"}

安装pod network

仅在Master节点执行，网络必须在任何应用程序之前部署。而且，kube-dns是一个内部帮助服务，在安装网络之前不会启动。 kubeadm仅支持基于容器网络接口（CNI）的网络（并且不支持kubenet） 安装Flannel # 将桥接的IPv4流量传递给iptables的链 sysctl net.bridge.bridge-nf-call-iptables=1 # [root@aniu-k8s ~]# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/v0.9.1/Documentation/kube-flannel.yml # kubectl apply -f  https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml clusterrole "flannel" created clusterrolebinding "flannel" created serviceaccount "flannel" created configmap "kube-flannel-cfg" created daemonset "kube-flannel-ds" created

一旦安装了pod网络，就可以通过在kubectl get pods –all-namespaces的输出中检查kube-dns pod是否正在运行来确认它正在工作。 一旦kube-dns吊舱启动并运行，您可以继续加入您的节点 [root@aniu-k8s ~]# kubectl get pods --all-namespaces NAMESPACE    NAME                              READY    STATUS              RESTARTS  AGE kube-system  etcd-aniu-k8s                      1/1      Running            0          1h kube-system  kube-apiserver-aniu-k8s            1/1      Running            0          1h kube-system  kube-controller-manager-aniu-k8s  1/1      Running            0          1h kube-system  kube-dns-6f4fd4bdf-2428k          0/3      ContainerCreating  0          1h kube-system  kube-flannel-ds-2h2c6              0/1      CrashLoopBackOff    3          1m kube-system  kube-proxy-wt74z                  1/1      Running            0          1h kube-system  kube-scheduler-aniu-k8s            1/1      Running            0          1h

注意：笔者安装pod network采用flannel有问题，故换成Weave Net export kubever=$(kubectl version | base64 | tr -d '\n') kubectl apply -f "https://cloud.weave.works/k8s/net?k8s-version=$kubever"

Master Isolation

使用kubeadm初始化的集群，出于安全考虑Pod不会被调度到Master Node上，可使用如下命令使Master节点参与工作负载。： [root@aniu-k8s ~]# kubectl taint nodes --all node-role.kubernetes.io/master- node "aniu-k8s" untainted

查看节点状态 [root@aniu-k8s ~]# kubectl get pod --all-namespaces -o wide NAMESPACE    NAME                                    READY    STATUS    RESTARTS  AGE      IP              NODE kube-system  etcd-aniu-k8s                          1/1      Running  0          49m      192.168.10.10  aniu-k8s kube-system  kube-apiserver-aniu-k8s                1/1      Running  0          49m      192.168.10.10  aniu-k8s kube-system  kube-controller-manager-aniu-k8s        1/1      Running  0          49m      192.168.10.10  aniu-k8s kube-system  kube-dns-6f4fd4bdf-n4ctn                3/3      Running  0          50m      10.32.0.2      aniu-k8s kube-system  kube-proxy-s5pnl                        1/1      Running  0          47m      192.168.0.209  aniu-saas-4 kube-system  kube-proxy-szs7k                        1/1      Running  0          50m      192.168.10.10  aniu-k8s kube-system  kube-scheduler-aniu-k8s                1/1      Running  0          49m      192.168.10.10  aniu-k8s kube-system  weave-net-bkbs2                        2/2      Running  0          49m      192.168.10.10  aniu-k8s kube-system  weave-net-cwvdk                        2/2      Running  0          47m      192.168.0.209  aniu-saas-4 # 可以看到全部的pod已经全部running

向K8s集群中加入节点

节点是工作负载（containers and pods）运行的地方。要将新节点添加到群集，请为每台机器执行以下操作： # 节点需要安装 yum install -y kubelet kubeadm kubectl

[root@aniu-saas-4 ~]# kubeadm join --token dc2313.9e3daddc83109625 192.168.10.10:6443 --discovery-token-ca-cert-hash sha256:8fe62dea8e88ff957dcd712f3c5948cc43f940abb3f34e8823576434d216ed5a [preflight] Running pre-flight checks.         [WARNING FileExisting-crictl]: crictl not found in system path [preflight] Starting the kubelet service [discovery] Trying to connect to API Server "192.168.10.10:6443" [discovery] Created cluster-info discovery client, requesting info from "https://192.168.10.10:6443" [discovery] Requesting info from "https://192.168.10.10:6443" again to validate TLS against the pinned public key [discovery] Cluster info signature and contents are valid and TLS certificate validates against pinned roots, will use API Server "192.168.10.10:6443" [discovery] Successfully established connection with API Server "192.168.10.10:6443"

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

Run 'kubectl get nodes' on the master to see this node join the cluster.

查看节点信息 [root@aniu-k8s ~]# kubectl get nodes NAME          STATUS    ROLES    AGE      VERSION aniu-k8s      Ready      master    1h        v1.9.2 aniu-saas-4  NotReady  <none>    17s      v1.9.2

从其他机器或者笔记本终端操作集群 scp root@<master ip>:/etc/kubernetes/admin.conf . kubectl --kubeconfig ./admin.conf get nodes

将API服务器代理到本地主机 scp root@<master ip>:/etc/kubernetes/admin.conf . kubectl --kubeconfig ./admin.conf proxy

删除Kubernetes集群节点 kubectl drain <node name> --delete-local-data --force --ignore-daemonsets kubectl delete node <node name>

注意事项 如果kubeadm出错，修改完成之后需要 kubeadm reset在重启初始化 官网文档只有修改docker配置哪一步，笔者没有操作，其他步骤和官网一致

错误 查看系统日志仍存在相关错误： # Error adding network: open /run/flannel/subnet.env: no such file or directory # oci-systemd-hook[12470]: systemdhook <debug>: Skipping as container command is /pause, not init or systemd # 后面继续学习排查故障

部署Dashboard插件 下载Dashboard配置文件 mkdir ~/k8s cd ~/k8s wget https://raw.githubusercontent.com/kubernetes/dashboard/master/src/deploy/recommended/kubernetes-dashboard.yaml

修改Dashboard Service，编辑kubernetes-dashboard.yaml文件，在Dashboard Service中添加type: NodePort，暴露Dashboard服务 # ------------------- Dashboard Service ------------------- #

kind: Service apiVersion: v1 metadata:   labels:     k8s-app: kubernetes-dashboard   name: kubernetes-dashboard   namespace: kube-system spec:   type: NodePort # 添加   ports:     - port: 443       targetPort: 8443   selector:     k8s-app: kubernetes-dashboard

安装Dashboard插件 [root@aniu-k8s k8s]# kubectl create -f kubernetes-dashboard.yaml secret "kubernetes-dashboard-certs" created serviceaccount "kubernetes-dashboard" created role "kubernetes-dashboard-minimal" created rolebinding "kubernetes-dashboard-minimal" created deployment "kubernetes-dashboard" created service "kubernetes-dashboard" created

Dashboard账户集群管理权限

创建一个kubernetes-dashboard-admin的ServiceAccount并授予集群admin的权限，创建kubernetes-dashboard-admin.rbac.yaml --- apiVersion: v1 kind: ServiceAccount metadata:   labels:     k8s-app: kubernetes-dashboard   name: kubernetes-dashboard-admin   namespace: kube-system --- apiVersion: rbac.authorization.k8s.io/v1beta1 kind: ClusterRoleBinding metadata:   name: kubernetes-dashboard-admin   labels:     k8s-app: kubernetes-dashboard roleRef:   apiGroup: rbac.authorization.k8s.io   kind: ClusterRole   name: cluster-admin subjects: - kind: ServiceAccount   name: kubernetes-dashboard-admin   namespace: kube-system

执行命令： [root@aniu-k8s ~]#  kubectl create -f kubernetes-dashboard-admin.rbac.yaml serviceaccount "kubernetes-dashboard-admin" created clusterrolebinding "kubernetes-dashboard-admin" created

查看kubernete-dashboard-admin的token [root@aniu-k8s ~]# kubectl -n kube-system get secret | grep kubernetes-dashboard-admin kubernetes-dashboard-admin-token-c9sq2          kubernetes.io/service-account-token  3        12s [root@aniu-k8s ~]# kubectl describe -n kube-system secret/kubernetes-dashboard-admin-token-c9sq2 Name:        kubernetes-dashboard-admin-token-c9sq2 Namespace:    kube-system Labels:      <none> Annotations:  kubernetes.io/service-account.name=kubernetes-dashboard-admin               kubernetes.io/service-account.uid=04821fef-061f-11e8-a2bc-d4ae528a3fba

Type:  kubernetes.io/service-account-token

Data ==== ca.crt:    1025 bytes namespace:  11 bytes token:      eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.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.csPOFxpLHxj-btcmUpOEUFO4MgL5wVL_lSuECALt9aLlb6x72lBRIQZfXnu8MbchhUlDBEX-i4dNU6_nyTKTokbiLwtCbKM12g7wG44aw1c-RjmFRvVxe9tMjjQXEN4ZExHoqtrcU5qTHrXo9qQOy5fyPBc6rbnS7YuPwp6tpofMO9WHdHCp0PejveAKSk6V6f-rPCZuh6ScfCYNF9ytLW-SGY4Kly9DXPR1AYgSdi7y1pu61iqWPgWUMqCzd5qsQ8ml4avOgK-jM-StqoG5_Rftk0sCVoVqfiN4toQhoC28_9TGBu0IKPiM-e1Fo6J4bZ8MrDULHnzs8lMWz1c0lQ

查看Dashboard服务端口 [root@aniu-k8s ~]# kubectl get svc -n kube-system NAME                  TYPE        CLUSTER-IP    EXTERNAL-IP  PORT(S)        AGE kube-dns              ClusterIP  10.96.0.10    <none>        53/UDP,53/TCP  14h kubernetes-dashboard  NodePort    10.96.219.54  <none>        443:30760/TCP  2m