准备工作
规划是使用两台服务器安装kubernetes集群，分别为：kube-1、kube-2。
修改ubuntu国内镜像源
我们这里使用阿里云的镜像，修改 /etc/apt/sources.list 为：
deb http://mirrors.aliyun.com/ubuntu/ xenial main deb-src http://mirrors.aliyun.com/ubuntu/ xenial main deb http://mirrors.aliyun.com/ubuntu/ xenial-updates main deb-src http://mirrors.aliyun.com/ubuntu/ xenial-updates main deb http://mirrors.aliyun.com/ubuntu/ xenial universe deb-src http://mirrors.aliyun.com/ubuntu/ xenial universe deb http://mirrors.aliyun.com/ubuntu/ xenial-updates universe deb-src http://mirrors.aliyun.com/ubuntu/ xenial-updates universe deb http://mirrors.aliyun.com/ubuntu/ xenial-security main deb-src http://mirrors.aliyun.com/ubuntu/ xenial-security main deb http://mirrors.aliyun.com/ubuntu/ xenial-security universe deb-src http://mirrors.aliyun.com/ubuntu/ xenial-security universe
添加kubernetes包仓库
并且执行以下命令安装kubernetes的软件源，参考：https://opsx.alibaba.com/mirror
apt-get update && apt-get install -y apt-transport-https curl https://mirrors.aliyun.com/kubernetes/apt/doc/apt-key.gpg | apt-key add - cat <<EOF >/etc/apt/sources.list.d/kubernetes.list deb https://mirrors.aliyun.com/kubernetes/apt/ kubernetes-xenial main EOF apt-get update apt-get install -y kubelet kubeadm kubectl
安装docker
apt-get install docker.io -y
随后启动docker
service docker start
如果需要普通用户执行docker命令，可以参考这篇文章进一步做设置：https://johng.cn/using-docker-without-root/
安装Kubernetes
在kube-1执行安装
我们现在kube-1节点上，使用 kubeadmin 工具包来安装kubernetes，使用以下命令初始化Kubernetes节点：
kubeadm init --image-repository mirrorgooglecontainers --kubernetes-version v1.13.2
其中，loads 为我个人创建的kubernetes镜像仓库，v1.13.2为指定需要安装的kubernetes版本，不同的版本依赖的docker镜像会不同。
执行后，输出结果如下：
root@kube-1:~# kubeadm init --image-repository mirrorgooglecontainers --kubernetes-version v1.13.2 [init] Using Kubernetes version: v1.13.2 [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 "front-proxy-ca" certificate and key [certs] Generating "front-proxy-client" certificate and key [certs] Generating "etcd/ca" certificate and key [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-1 localhost] and IPs [192.168.1.9 127.0.0.1 ::1] [certs] Generating "etcd/peer" certificate and key [certs] etcd/peer serving cert is signed for DNS names [kube-1 localhost] and IPs [192.168.1.9 127.0.0.1 ::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-1 kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 192.168.1.9] [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 28.005808 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-1" as an annotation [mark-control-plane] Marking the node kube-1 as control-plane by adding the label "node-role.kubernetes.io/master=''" [mark-control-plane] Marking the node kube-1 as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule] [bootstrap-token] Using token: xvm4rc.qmlh7m5uprqfjt9g [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-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 192.168.1.9:6443 --token xvm4rc.qmlh7m5uprqfjt9g --discovery-token-ca-cert-hash sha256:bab0a640108a524fefd4574ccb9f63273087936fd403f4b51d6217b903cbf400 root@kube-1:~#
根据提示，初始化完成之后我们需要执行以下命令安装kubectl的配置文件：
mkdir -p $HOME/.kube sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config sudo chown $(id -u):$(id -g) $HOME/.kube/config
此外，需要注意的是这一段，记录下来，以便后续添加其他节点进入集群：
kubeadm join 192.168.1.9:6443 --token xvm4rc.qmlh7m5uprqfjt9g --discovery-token-ca-cert-hash sha256:bab0a640108a524fefd4574ccb9f63273087936fd403f4b51d6217b903cbf400
在kube-2上执行安装
在kube-2节点上完成准备工作后不要执行kubeadmin init指令，而是需要执行kubeadmin join指令加入节点：
root@kube-2:~# kubeadm join 192.168.1.9:6443 --token xvm4rc.qmlh7m5uprqfjt9g --discovery-token-ca-cert-hash sha256:bab0a640108a524fefd4574ccb9f63273087936fd403f4b51d6217b903cbf400 [preflight] Running pre-flight checks [discovery] Trying to connect to API Server "192.168.1.9:6443" [discovery] Created cluster-info discovery client, requesting info from "https://192.168.1.9:6443" [discovery] Requesting info from "https://192.168.1.9:6443" 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 "192.168.1.9:6443" [discovery] Successfully established connection with API Server "192.168.1.9:6443" [join] Reading configuration from the cluster... [join] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml' [kubelet] Downloading configuration for the kubelet from the "kubelet-config-1.13" 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 [tlsbootstrap] Waiting for the kubelet to perform the TLS Bootstrap... [patchnode] Uploading the CRI Socket information "/var/run/dockershim.sock" to the Node API object "kube-2" as an annotation 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 master to see this node join the cluster. root@kube-2:~#
如果之前已经初始化过节点，可随时通过kubeadmin reset指令重置当前节点配置，并使用service kubelet restart重启kubelet服务，随后再通过kubeadmin join指令加入集群。
Kubernetes常见问题
1、runtime network not ready: NetworkReady=false reason:NetworkPluginNotReady message:docker: network plugin is not ready: cni config uninitialized
原因：
因为kubelet配置了network-plugin=cni，但是还没安装，所以状态会是NotReady,不想看这个报错或者不需要网络，就可以修改kubelet配置文件，去掉network-plugin=cni 就可以了。
解决：
vim /etc/systemd/system/kubelet.service.d/10-kubeadm.conf
删除最后一行里的$KUBELET_NETWORK_ARGS ，1.11.2+版本的封装在 /var/lib/kubelet/kubeadm-flags.env 文件中。