使用|使用 kubeadm 部署 kubernetes 1.14.2 集群

使用|使用 kubeadm 部署 kubernetes 1.14.2 集群
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之前在研究spring cloud Data Flow时有部署过 kubernetes,不过使用的是minikube搭建的,正好这几天在极客时间学习《深入剖析 kubernetes》专栏,依据专栏里的搭建步骤和网上的相关教程搭建了1.14.2版本的集群。
环境规划 由于没有足够的云主机,我在本地使用虚拟机搭建的,具体各个节点的配置如下:

IP地址 系统版本 内存 角色
10.211.55.8 CentOS 7.6 4GB Master(主节点)
10.211.55.9 CentOS 7.6 4GB Worker(从节点)
每个节点需要安装的软件及版本如下:
软件名称 版本 说明
Docker 18.09.6 负责创建、拉取容器
kubeadm 1.14.2-0 负责初始化k8s集群
kubelet 1.14.2-0 运行在所有节点上,负责启动容器和Pod
kubectl 1.14.2-0 k8s命令行工具,负责与k8s集群交互,例如部署应用
环境准备 使用Vmware或其他虚拟机管理工具安装两台CentOS7.6的步骤这里就不介绍了,下面是为了保证我们能正常使用kubeadm启动kubernetes所需要做到前提工作。
系统配置
为了方便之后能快速辨识哪台主机是什么类型的节点,我们需要为每台主机设置代表其节点身份主机名,具体如下:
# 为 10.211.55.8 主节点设置主机名 hostnamectl --static set-hostnamemaster # 为 10.211.55.9 从节点设置主机名 hostnamectl --static set-hostnameworker

【使用|使用 kubeadm 部署 kubernetes 1.14.2 集群】另外还需要在每台主机/etc/hosts文件中加上解析配置
vim /etc/hosts #写入如下类型,IP根据自己实际情况修改10.211.55.8 master 10.211.55.9 worker

如果各个主机启用了防火墙,则我们需要开放kubernetes各个组件所需要的端口,这里搭建是测试环境,只需要禁用各个节点的防火墙即可:
# 注意以下命令是下次生效 systemctl disable firewalld.service systemctl stop firewalld.service# 关闭防火墙立即生效 iptables -F# 防火墙关闭后可以使用以下命令查看防火墙状态 systemctl status firewalld

禁用SELINUX(它是一个 Linux 内核模块,也是 Linux 的一个安全子系统)
##设置SELinux 成为permissive模式(不用重启机器) setenforce 0# 修改配置文件 (重启机器生效) vim /etc/selinux/config SELINUX=disabled

关闭Swap分区
swapoff -a

修改 /etc/fstab 文件,注释掉 SWAP 的自动挂载,使用free -m确认Swap已经关闭。
创建/etc/sysctl.d/k8s.conf文件,添加如下内容:
# 配置路由 net.bridge.bridge-nf-call-ip6tables = 1 net.bridge.bridge-nf-call-iptables = 1 net.ipv4.ip_forward = 1 # swappiness 参数设为 0 vm.swappiness=0

执行下面命令使修改生效
modprobe br_netfilter sysctl -p /etc/sysctl.d/k8s.conf

软件安装
安装Docker。这里安装步骤完成依据官网,可以参考官网了解更多
  • 如果之前安装过,卸载旧版本
    sudo yum remove docker \ docker-client \ docker-client-latest \ docker-common \ docker-latest \ docker-latest-logrotate \ docker-logrotate \ docker-engine

  • 安装所需的包
    sudo yum install -y yum-utils \ device-mapper-persistent-data \ lvm2

  • 设置稳定版本(stable)存储库
    sudo yum-config-manager \ --add-repo \ https://download.docker.com/linux/centos/docker-ce.repo

  • 由于kubernetes 1.4支持的Docker版本最高为18.09,所以这里我们安装的Docker版本为18.09.7
    sudo yum install docker-ce-18.09.7 docker-ce-cli-18.09.7 containerd.io

  • 启动Docker和设置开机自启
    systemctl start docker systemctl enable docker

  • 修改docker cgroup driversystemd
    vim /etc/docker/daemon.json # 写入如下内容 { "exec-opts": ["native.cgroupdriver=systemd"] }

  • 重启Docker
    systemctl restart docker

安装kubeadmkubectlkubelet三个组件
  • 安装之前我们需要先添加yum源,命令如下:
    cat < /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

  • 接着使用如下命令安装1.14.2版本的各个组件
    yum install -y kubelet-1.14.2 kubeadm-1.14.2 kubectl-1.14.2

镜像拉取
由于k8s的许多镜像如果我们直接下是下载不下来的,所以我们需要想办法先将集群所需的所有镜像都下载好。好在阿里云提供了镜像文件,我们只需要执行下面命令即可
  • 拉取所需镜像文件
    docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/pause:3.1 docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/kube-controller-manager:v1.14.2 docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/kube-scheduler:v1.14.2 docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/kube-proxy:v1.14.2 docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/kube-apiserver:v1.14.2 docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/etcd:3.3.10 docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/coredns:1.3.1 docker pull registry.cn-shenzhen.aliyuncs.com/cp_m/flannel:v0.10.0-amd64 docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/kubernetes-dashboard-amd64:v1.10.1

  • 给镜像打标签
    docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-apiserver:v1.14.2 k8s.gcr.io/kube-apiserver:v1.14.2 docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-controller-manager:v1.14.2 k8s.gcr.io/kube-controller-manager:v1.14.2 docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-scheduler:v1.14.2 k8s.gcr.io/kube-scheduler:v1.14.2 docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-proxy:v1.14.2 k8s.gcr.io/kube-proxy:v1.14.2 docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/pause:3.1 k8s.gcr.io/pause:3.1 docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/etcd:3.3.10 k8s.gcr.io/etcd:3.3.10 docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/coredns:1.3.1 k8s.gcr.io/coredns:1.3.1 docker tag registry.cn-shenzhen.aliyuncs.com/cp_m/flannel:v0.10.0-amd64 quay.io/coreos/flannel:v0.10.0-amd64 docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kubernetes-dashboard-amd64:v1.10.1 k8s.gcr.io/kubernetes-dashboard-amd64:v1.10.1

  • 删除拉取的初始镜像,只留打上标签的镜像
    docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/kube-apiserver:v1.14.2 docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/kube-controller-manager:v1.14.2 docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/kube-scheduler:v1.14.2 docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/kube-proxy:v1.14.2 docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/pause:3.1 docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/etcd:3.3.10 docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/coredns:1.3.1 docker rmi registry.cn-shenzhen.aliyuncs.com/cp_m/flannel:v0.10.0-amd64 docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/kubernetes-dashboard-amd64:v1.10.1

    上面步骤执行完成之后,我们使用docker images命令就能看到所有镜像了,显示如下
    [root@Node1 ~]# docker images REPOSITORYTAGIMAGE IDCREATEDSIZE k8s.gcr.io/kube-proxyv1.14.25c24210246bb10 months ago82.1MB k8s.gcr.io/kube-apiserverv1.14.25eeff402b65910 months ago210MB k8s.gcr.io/kube-controller-managerv1.14.28be94bdae13910 months ago158MB k8s.gcr.io/kube-schedulerv1.14.2ee18f350636d10 months ago81.6MB k8s.gcr.io/coredns1.3.1eb516548c18014 months ago40.3MB k8s.gcr.io/kubernetes-dashboard-amd64v1.10.1f9aed6605b8115 months ago122MB k8s.gcr.io/etcd3.3.102c4adeb21b4f16 months ago258MB quay.io/coreos/flannelv0.10.0-amd64f0fad859c9092 years ago44.6MB k8s.gcr.io/pause

安装配置Kubernetes集群 Master 节点初始化
我们使用如下命令来初始化kubernetes
# --kubernetes-version=v1.14.2 指定安装的k8s版本 # --apiserver-advertise-address 指定 Master 节点的 advertise address,也就是 IP 地址 # --pod-network-cidr 用于指定Pod的网络范围,下面采用的是flannel方案(https://github.com/coreos/flannel/blob/master/Documentation/kubernetes.md) kubeadm init --kubernetes-version=v1.14.2 --apiserver-advertise-address 10.211.55.8 --pod-network-cidr=10.244.0.0/16

执行之后,会有如下输出
[init] Using Kubernetes version: v1.14.2 [preflight] Running pre-flight checks [preflight] Pulling images required for setting up a Kubernetes cluster [preflight] This might take a minute or two, depending on the speed of your internet connection [preflight] You can also perform this action in beforehand using 'kubeadm config images pull' [kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env" [kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml" [kubelet-start] Activating the kubelet service [certs] Using certificateDir folder "/etc/kubernetes/pki" [certs] Generating "etcd/ca" certificate and key [certs] Generating "etcd/peer" certificate and key [certs] etcd/peer serving cert is signed for DNS names [master localhost] and IPs [10.211.55.8 127.0.0.1 ::1] [certs] Generating "etcd/healthcheck-client" certificate and key [certs] Generating "apiserver-etcd-client" certificate and key [certs] Generating "etcd/server" certificate and key [certs] etcd/server serving cert is signed for DNS names [master localhost] and IPs [10.211.55.8 127.0.0.1 ::1] [certs] Generating "ca" certificate and key [certs] Generating "apiserver-kubelet-client" certificate and key [certs] Generating "apiserver" certificate and key [certs] apiserver serving cert is signed for DNS names [master kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 10.211.55.8] [certs] Generating "front-proxy-ca" certificate and key [certs] Generating "front-proxy-client" certificate and key [certs] Generating "sa" key and public key [kubeconfig] Using kubeconfig folder "/etc/kubernetes" [kubeconfig] Writing "admin.conf" kubeconfig file [kubeconfig] Writing "kubelet.conf" kubeconfig file [kubeconfig] Writing "controller-manager.conf" kubeconfig file [kubeconfig] Writing "scheduler.conf" kubeconfig file [control-plane] Using manifest folder "/etc/kubernetes/manifests" [control-plane] Creating static Pod manifest for "kube-apiserver" [control-plane] Creating static Pod manifest for "kube-controller-manager" [control-plane] Creating static Pod manifest for "kube-scheduler" [etcd] Creating static Pod manifest for local etcd in "/etc/kubernetes/manifests" [wait-control-plane] Waiting for the kubelet to boot up the control plane as static Pods from directory "/etc/kubernetes/manifests". This can take up to 4m0s [apiclient] All control plane components are healthy after 16.501690 seconds [upload-config] storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace [kubelet] Creating a ConfigMap "kubelet-config-1.14" in namespace kube-system with the configuration for the kubelets in the cluster [upload-certs] Skipping phase. Please see --experimental-upload-certs [mark-control-plane] Marking the node k8s-master as control-plane by adding the label "node-role.kubernetes.io/master=''" [mark-control-plane] Marking the node k8s-master as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule] [bootstrap-token] Using token: y6awgp.6bvxt8l3rie2du5s [bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles [bootstrap-token] configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials [bootstrap-token] configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token [bootstrap-token] configured RBAC rules to allow certificate rotation for all node client certificates in the cluster [bootstrap-token] creating the "cluster-info" ConfigMap in the "kube-public" namespace [addons] Applied essential addon: CoreDNS [addons] Applied essential addon: kube-proxyYour 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/configYou 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 10.211.55.8:6443 --token br6a7j.79aimgudzio73jy5 \ --discovery-token-ca-cert-hash sha256:0623e22780c5a25138208fc417f874a0c70ca28543acf52be52ee445ec0c1dd3

我们使用如下命令来配置kubectl
# root 模式下导入环境变量 export KUBECONFIG=/etc/kubernetes/admin.conf# 重启 kubelet systemctl restart kubelet

添加连接集群的 config 配置
正如初始化之后打印出来的命令,我们需要执行下面命令操作:
mkdir -p $HOME/.kube cp -i /etc/kubernetes/admin.conf $HOME/.kube/config chown $(id -u):$(id -g) $HOME/.kube/config

安装 flannel 网络插件
我们可以使用如下命令来安装。如果wget下载kube-flannel.yml失败了,建议到浏览器下载好之后再试
wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.ymlkubectl apply -f kube-flannel.yml

安装完成之后,我们可以使用kubectl get pods -o wide --all-namespaces来查看目前集群中的所有pod信息;使用kubectl get node来查看目前集群中的节点信息,例如:
[root@Node1 ~]# kubectl get node NAMESTATUSROLESAGEVERSION masterReadymaster7d1hv1.14.2

Worker 节点加入集群
注意,Worker节点需要安装配置环境准备里的所有内容。
其他节点加入集群的方式在集群初始化之后最后也打印出来了,如果我们忘记了或找不到了,可以在Master节点使用如下命令来获取 join token
kubeadm token create --print-join-command

执行完成之后打印如下类似信息:
kubeadm join 10.211.55.8:6443 --token e6gc7z.t52g39w7mxww18gn \ --discovery-token-ca-cert-hash sha256:603fbd109caf000c0cffe286c7b2eeebaf88d0540e1ea226d7f1b239d0695f1e[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 filewith 'kubectl -n kube-system get cm kubeadm-config -oyaml' [kubeelet-start] Downloading configuration for the kubelet from the "kubelet-config-1.14" 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] Activating the kubelet service [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.

于是我们就可以再Worker节点执行如下命令来加入到集群之中
# 基础命令示例 kubeadm join --token : --discovery-token-ca-cert-hash sha256:kubeadm join 10.211.55.8:6443 --token e6gc7z.t52g39w7mxww18gn \ --discovery-token-ca-cert-hash sha256:603fbd109caf000c0cffe286c7b2eeebaf88d0540e1ea226d7f1b239d0695f1e

加入之后,我们就可以使用kubectl get node -o wide来查看集群节点的状态信息
[root@Node1 ~]# kubectl get node -o wide NAMESTATUSROLESAGEVERSIONINTERNAL-IPEXTERNAL-IPOS-IMAGEKERNEL-VERSIONCONTAINER-RUNTIME node1Readymaster7d1hv1.14.210.211.55.8CentOS Linux 7 (Core)3.10.0-1062.el7.x86_64docker://18.9.7 node2Ready7d1hv1.14.210.211.55.9CentOS Linux 7 (Core)3.10.0-1062.el7.x86_64docker://18.9.7

到这里,一个具有两个节点的kubernetes集群就搭建好了。
集群重置或删除
如果想要重置或删除集群,我们可以结合下面几个命令来实现
  • 删除子节点
    # 查询k8s集群所以节点 kubectl get nodes# 删除子节点 , 代表子节点名称 kubectl drain --delete-local-data --force --ignore-daemonsets kubectl delete node

  • 重置节点
    # 主节点和子节点都能使用该命令重置 kubeadm reset# 如果想要删除节点上的集群文件,可以使用如下命令 rm -f $HOME/.kube/

安装配置 Dashborad 安装 Dashborad
Kubernetes Dashborad是一个集群可视化管理工具,我们在上面的镜像拉取中已经拉取了镜像,现在我们需要在集群中安装Dashborad。
先使用如下命令下载YAML配置文件
wget https://raw.githubusercontent.com/kubernetes/dashboard/v1.10.1/src/deploy/recommended/kubernetes-dashboard.yaml

为了实现外网访问,我们首先需要使用vim kubernetes-dashboard.yaml来编辑下载的YAML文件,在Service控制器中添加NodePort类型,具体内容如下:
# ------------------- Dashboard Service ------------------- #kind: Service apiVersion: v1 metadata: labels: k8s-app: kubernetes-dashboard name: kubernetes-dashboard namespace: kube-system spec: ports: - port: 443 targetPort: 8443 nodePort: 31234 selector: k8s-app: kubernetes-dashboard type: NodePort

编辑完成之后,保存退出,然后使用下面命令来创建kubernetes-dashborad
kubectl apply -f kubernetes-dashboard.yaml

完成之后,我们就可以使用如下命令来查看dashborad的状态和service端口
[root@Node1 ~]# kubectl get service -n kube-system NAMETYPECLUSTER-IPEXTERNAL-IPPORT(S)AGE kube-dnsClusterIP10.96.0.1053/UDP,53/TCP,9153/TCP7d2h kubernetes-dashboardNodePort10.102.72.239443:31234/TCP7d [root@Node1 ~]# kubectl get pods -n kube-system NAMEREADYSTATUSRESTARTSAGE coredns-fb8b8dccf-pdq9j1/1Running17d2h coredns-fb8b8dccf-pj6lk1/1Running17d2h etcd-node11/1Running17d2h kube-apiserver-node11/1Running17d2h kube-controller-manager-node11/1Running27d2h kube-flannel-ds-amd64-jtwgg1/1Running17d1h kube-flannel-ds-amd64-vl5hn1/1Running17d2h kube-proxy-227461/1Running17d2h kube-proxy-4tx621/1Running17d1h kube-scheduler-node11/1Running37d2h kubernetes-dashboard-5f7b999d65-59k421/1Running17d

配置Dashborad
为了能在浏览器中访问dashboard,我们必须要先配置https证书。首先我们使用如下命令来生成私钥和证书签名
openssl genrsa -des3 -passout pass:x -out dashboard.pass.key 2048 openssl rsa -passin pass:x -in dashboard.pass.key -out dashboard.key rm dashboard.pass.key # 下面命令,一路回车 openssl req -new -key dashboard.key -out dashboard.csr

然后使用命令生成SSL证书
openssl x509 -req -sha256 -days 365 -in dashboard.csr -signkey dashboard.key -out dashboard.crt

在所有节点使用如下命令创建证书的挂载目录
mkdir -p /var/share/certs

然后回到Master节点将生成的dashboard.keydashboard.crt拷贝到/var/share/certs目录下
创建admin-token.yaml文件,写入如下内容并保存
kind: ClusterRoleBinding apiVersion: rbac.authorization.k8s.io/v1beta1 metadata: name: adm annotations: rbac.authorization.kubernetes.io/autoupdateee: "true" roleRef: kind: ClusterRole name: cluster-admin apiGroup: rbac.authorization.k8s.io subjects: - kind: ServiceAccount name: admin namespace: kube-system --- apiVersion: v1 kind: ServiceAccount metadata: name: admin namespace: kube-system labels: kubernetes.io/cluster-service: "true" addonmanager.kubernetes.io/mode: Reconcile

执行kubectl create -f admin-token.yaml命令后,我们使用如下命令即可查看登入dashboradtoken
kubectl get secret $(kubectl get secret -n kube-system|grep admin-token|awk '{print $1}') -n kube-system -o jsonpath={.data.token}|base64 -d |xargs echo

在浏览器输入:https://IP:31234,然后选择使用令牌登录,将上一步命令输出的token粘入即可登录
参考
  • 使用kubeadm安装Kubernetes 1.15
  • kubernetes-1.14.2集群安装和dashbaord面板
  • Kubeadm 部署 Kubernetes 1.14.2 集群

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