kubeadm中如何安装Kubernetes集群

kubeadm中如何安装Kubernetes集群，针对这个问题，这篇文章详细介绍了相对应的分析和解答，希望可以帮助更多想解决这个问题的小伙伴找到更简单易行的方法。

1，修改主机名

//master 192.168.2.211hostnamectl set-hostname kube-master//node1 192.168.2.212hostnamectl set-hostname kube-node1//node1 192.168.2.213hostnamectl set-hostname kube-node2

2， 关闭防火墙

systemctl stop firewalld && systemctl disable firewalld

3，关闭selinux，必须修改允许容器访问主机文件系统

//临时setenforce 0//永久sed -i "s/SELINUX=enforcing/SELINUX=disabled/g" /etc/sysconfig/selinux

4，关闭swap，否则会报错

//临时swapoff -a//永久vi /etc/fstab 注释掉/dev/mapper/cl-swap那一行

如图

修改永久关闭的配置，需要重启系统

5，安装docker

官方文档说已验证的docker版本为1.11.1, 1.12.1, 1.13.1, 17.03, 17.06, 17.09, 18.06（https://github.com/kubernetes/kubernetes/blob/master/CHANGELOG-1.13.md#external-dependencies），但是在测试中使用1.13之前版本时遇到很多问题，所以这里使用目前最新版18。

sudo yum install -y yum-utilssudo yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.reposudo yum install -y docker-cesystemctl start docker && systemctl enable docker

版本：

[root@kube-master ~]# docker versionClient: Version:           18.09.0 API version:       1.39 Go version:        go1.10.4 Git commit:        4d60db4 Built:             Wed Nov  7 00:48:22 2018 OS/Arch:           linux/amd64 Experimental:      falseServer: Docker Engine - Community Engine:  Version:          18.09.0  API version:      1.39 (minimum version 1.12)  Go version:       go1.10.4  Git commit:       4d60db4  Built:            Wed Nov  7 00:19:08 2018  OS/Arch:          linux/amd64  Experimental:     false

6，安装kubeadm，kubelet，kubectl

cat < /etc/yum.repos.d/kubernetes.repo[kubernetes]name=Kubernetesbaseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-\$basearchenabled=1gpgcheck=1repo_gpgcheck=1gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg https://packages.cloud.google.com/yum/doc/rpm-package-key.gpgEOFyum install -y kubelet kubeadm kubectlsystemctl enable kubelet && systemctl start kubelet

官方提供的安装地址在墙外，如果服务器在国内，可以使用阿里的源（https://opsx.alibaba.com/mirror?lang=zh-cn）。

cat < /etc/yum.repos.d/kubernetes.repo[kubernetes]name=Kubernetesbaseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/enabled=1gpgcheck=1repo_gpgcheck=1gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpgEOFyum install -y kubelet kubeadm kubectlsystemctl enable kubelet && systemctl start kubelet

版本：

这一步我没遇到，但是官方文档说某些 RHEL/CentOS 7系统会出现由于iptables被绕过，流量被错误地路由的问题。需要确保sysctl配置中net.bridge.bridge-nf-call-iptables的值为1：

cat <  /etc/sysctl.d/k8s.confnet.bridge.bridge-nf-call-ip6tables = 1net.bridge.bridge-nf-call-iptables = 1EOFsysctl --system

在测试时发现老版本docker驱动不是cgroupfs，导致kubernetes报错。查看驱动版本：

docker info | grep -i cgroup

如果不是需要修改kubernetes配置：

vi /etc/default/kubeletKUBELET_EXTRA_ARGS=--cgroup-driver=改为当前驱动systemctl daemon-reloadsystemctl restart kubelet

7，下载服务所需镜像

可以跳过，初始化会自动下载，但是因为有墙，所以需要尽量提前准备好。首先设置docker代理，

mkdir /etc/systemd/system/docker.service.dcat < /etc/systemd/system/docker.service.d/http-proxy.conf[Service]Environment="HTTP_PROXY=http://192.168.2.100:1080"EOFsystemctl daemon-reloadsystemctl restart docker

下载镜像

kubeadm config images pull --kubernetes-version v1.13.0

得到镜像如下

8，初始化master

kubeadm init --apiserver-advertise-address=192.168.2.211 --kubernetes-version=v1.13.0 --pod-network-cidr=10.244.0.0/16

--apiserver-advertise-address：api-server服务监听地址，即master的ip

--kubernetes-version：指定要部署的kubernetes版本，此处为1.13.0

--pod-network-cidr：指定pod网络分配地址范围。需要与下一步要使用的插件的配置一致，此处使用Flannel

[init] Using Kubernetes version: v1.13.0[preflight] Running pre-flight checks        [WARNING SystemVerification]: this Docker version is not on the list of validated versions: 18.09.0. Latest validated version: 18.06        [WARNING Hostname]: hostname "kube-master" could not be reached        [WARNING Hostname]: hostname "kube-master": lookup kube-master on 192.168.2.1:53: no such host[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 "front-proxy-ca" certificate and key[certs] Generating "front-proxy-client" certificate and key[certs] Generating "etcd/ca" certificate and key[certs] Generating "etcd/peer" certificate and key[certs] etcd/peer serving cert is signed for DNS names [kube-master localhost] and IPs [192.168.2.211 127.0.0.1 ::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 [kube-master localhost] and IPs [192.168.2.211 127.0.0.1 ::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 [kube-master kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 192.168.2.211][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 23.502901 seconds[uploadconfig] storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace[kubelet] Creating a ConfigMap "kubelet-config-1.13" in namespace kube-system with the configuration for the kubelets in the cluster[patchnode] Uploading the CRI Socket information "/var/run/dockershim.sock" to the Node API object "kube-master" as an annotation[mark-control-plane] Marking the node kube-master as control-plane by adding the label "node-role.kubernetes.io/master=''"[mark-control-plane] Marking the node kube-master as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule][bootstrap-token] Using token: thmy85.7ahn8zezyt6m39yy[bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles[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: CoreDNS[addons] Applied essential addon: kube-proxyYour 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/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/You can now join any number of machines by running the following on each nodeas root:  kubeadm join 192.168.2.211:6443 --token thmy85.7ahn8zezyt6m39yy --discovery-token-ca-cert-hash sha256:576442c07cb68e731badb48f15d28d701fa184f1dffc78556ebe834f8a651021

9，创建配置文件

上一步输出中提示创建配置文件，否则执行kubectl会报错。如：

按照提示执行

mkdir -p $HOME/.kubesudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/configsudo chown $(id -u):$(id -g) $HOME/.kube/config

再次执行

[root@kube-master ~]# kubectl get nodesNAME          STATUS     ROLES    AGE     VERSIONkube-master   NotReady   master   3m18s   v1.13.1

10, 安装Pod网络插件，使Pod可以相互通信。

kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

11，启动node

切换到node服务器，重复步骤1~7。执行第七步初始化master时最后打印的命令，如

kubeadm join 192.168.2.211:6443 --token thmy85.7ahn8zezyt6m39yy --discovery-token-ca-cert-hash sha256:576442c07cb68e731badb48f15d28d701fa184f1dffc78556ebe834f8a651021

完成后，回到master执行：watch kubectl get nodes，直到状态变为Ready

NAME          STATUS   ROLES    AGE     VERSIONkube-master   Ready    master   27m     v1.13.1kube-node1    Ready       9m19s   v1.13.1kube-node2    Ready       5m36s   v1.13.1

12，测试

在master上创建文件nginx.yaml，创建一个deployment并通过service发布。

apiVersion: apps/v1kind: Deploymentmetadata:  name: nginx-deplospec:  replicas: 2  selector:    matchLabels:      run: nginx-deploy  template:    metadata:      labels:        run: nginx-deploy    spec:      containers:      - name: nginx        image: nginx:1.7.9        ports:        - containerPort: 80---apiVersion: v1kind: Servicemetadata:  name: nginx-service  labels:    run: nginx-deployspec:  type: NodePort  ports:  - port: 80    targetPort: 80    nodePort: 30001  selector:    run: nginx-deploy

执行

kubectl create -f service.yamlwatch kubectl get deploy

等待状态Ready后，测试服务。

nginx成功返回说明服务已启动。在两个Node上执行docker ps，可以看到每个node各启动了一个nginx容器。

另外，我把镜像传到了七牛云上，可以按照命令下载使用

docker pull reg.qiniu.com/fgding/kube-proxy:v1.13.0docker pull reg.qiniu.com/fgding/kube-controller-manager:v1.13.0docker pull reg.qiniu.com/fgding/kube-apiserver:v1.13.0docker pull reg.qiniu.com/fgding/kube-scheduler:v1.13.0docker pull reg.qiniu.com/fgding/coredns:1.2.6docker pull reg.qiniu.com/fgding/etcd:3.2.24docker pull reg.qiniu.com/fgding/pause:3.1docker tag reg.qiniu.com/fgding/kube-proxy:v1.13.0  k8s.gcr.io/kube-proxy:v1.13.0 docker tag reg.qiniu.com/fgding/kube-controller-manager:v1.13.0 k8s.gcr.io/kube-controller-manager:v1.13.0docker tag reg.qiniu.com/fgding/kube-apiserver:v1.13.0 k8s.gcr.io/kube-apiserver:v1.13.0 docker tag reg.qiniu.com/fgding/kube-scheduler:v1.13.0 k8s.gcr.io/kube-scheduler:v1.13.0 docker tag reg.qiniu.com/fgding/coredns:1.2.6 k8s.gcr.io/coredns:1.2.6docker tag reg.qiniu.com/fgding/etcd:3.2.24 k8s.gcr.io/etcd:3.2.24docker tag reg.qiniu.com/fgding/pause:3.1  k8s.gcr.io/pause:3.1

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