kubeadm is designed to be a simple way for new users to start trying Kubernetes out, possibly for the first time, a way for existing users to test their application on and stitch together a cluster easily, and also to be a building block in other ecosystem and/or installer tool with a larger scope. kubeadm是一个python写的项目，代码在这里，用来帮助快速部署Kubernetes集群环境，但是目前仅仅是作为测试环境使用，如果你想在生产环境使用，可是要三思。
本文所用的环境：
虚拟机软件：VirtualBox
操作系统：Centos 7.3 minimal 安装
网卡：两块网卡，一块 Host-Only方式，一块 Nat 方式。
网络规划：
Master:192.168.0.101
Node:192.168.0.102-104
0.1 关掉 selinux
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$ setenforce 0 $ sed -i "s/^SELINUX=enforcing/SELINUX=disabled/g" /etc/sysconfig/selinux
[root@devops-101 ~]# kubeadm init --kubernetes-version=v1.11.0 --pod-network-cidr=10.244.0.0/16 --apiserver-advertise-address=192.168.0.101 [init] using Kubernetes version: v1.11.0 [preflight] running pre-flight checks I0724 08:36:35.636931 3409 kernel_validator.go:81] Validating kernel version I0724 08:36:35.637052 3409 kernel_validator.go:96] Validating kernel config [WARNING Hostname]: hostname "devops-101" could not be reached [WARNING Hostname]: hostname "devops-101" lookup devops-101 on 172.20.10.1:53: no such host [WARNING Service-Kubelet]: kubelet service is not enabled, please run 'systemctl enable kubelet.service' [preflight/images] Pulling images required for setting up a Kubernetes cluster [preflight/images] This might take a minute or two, depending on the speed of your internet connection [preflight/images] You can also perform this action in beforehand using 'kubeadm config images pull' [kubelet] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env" [kubelet] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml" [preflight] Activating the kubelet service [certificates] Generated ca certificate and key. [certificates] Generated apiserver certificate and key. [certificates] apiserver serving cert is signed for DNS names [devops-101 kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 192.168.0.101] [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] Generated etcd/ca certificate and key. [certificates] Generated etcd/server certificate and key. [certificates] etcd/server serving cert is signed for DNS names [devops-101 localhost] and IPs [127.0.0.1 ::1] [certificates] Generated etcd/peer certificate and key. [certificates] etcd/peer serving cert is signed for DNS names [devops-101 localhost] and IPs [192.168.0.101 127.0.0.1 ::1] [certificates] Generated etcd/healthcheck-client certificate and key. [certificates] Generated apiserver-etcd-client certificate and key. [certificates] valid certificates and keys now exist in"/etc/kubernetes/pki" [kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/admin.conf" [kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/kubelet.conf" [kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/controller-manager.conf" [kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/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 46.002877 seconds [uploadconfig] storing the configuration used in ConfigMap "kubeadm-config"in the "kube-system" Namespace [kubelet] Creating a ConfigMap "kubelet-config-1.11"in namespace kube-system with the configuration for the kubelets in the cluster [markmaster] Marking the node devops-101 as master by adding the label "node-role.kubernetes.io/master=''" [markmaster] Marking the node devops-101 as master by adding the taints [node-role.kubernetes.io/master:NoSchedule] [patchnode] Uploading the CRI Socket information "/var/run/dockershim.sock" to the Node API object "devops-101" as an annotation [bootstraptoken] using token: wkj0bo.pzibll6rd9gyi5z8 [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:
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:
[root@devops-101 ~]# export KUBECONFIG=/etc/kubernetes/admin.conf [root@devops-101 ~]# kubectl get nodes NAME STATUS ROLES AGE VERSION devops-101 NotReady master 7m v1.11.1 [root@devops-101 ~]# kubectl get pods --all-namespaces NAMESPACE NAME READY STATUS RESTARTS AGE kube-system coredns-78fcdf6894-8sd6g 0/1 Pending 0 7m kube-system coredns-78fcdf6894-lgvd9 0/1 Pending 0 7m kube-system etcd-devops-101 1/1 Running 0 6m kube-system kube-apiserver-devops-101 1/1 Running 0 6m kube-system kube-controller-manager-devops-101 1/1 Running 0 6m kube-system kube-proxy-bhmj8 1/1 Running 0 7m kube-system kube-scheduler-devops-101 1/1 Running 0 6m
可以看到节点还没有Ready，dns的两个pod也没不正常，还需要安装网络配置。
3. Master节点的网络配置
这里我选用了 Flannel 的方案。
kubeadm only supports Container Network Interface (CNI) based networks (and does not support kubenet).
修改系统设置，创建 flannel 网络。
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[root@devops-101 ~]# sysctl net.bridge.bridge-nf-call-iptables=1 net.bridge.bridge-nf-call-iptables = 1 [root@devops-101 ~]# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/v0.10.0/Documentation/kube-flannel.yml clusterrole.rbac.authorization.k8s.io/flannel created clusterrolebinding.rbac.authorization.k8s.io/flannel created serviceaccount/flannel created configmap/kube-flannel-cfg created daemonset.extensions/kube-flannel-ds created
$ docker tag registry.cn-hangzhou.aliyuncs.com/k8sth/pause-amd64:3.1 k8s.gcr.io/pause:3.1
两台服务器时间不同步。
报错信息
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[discovery] Failed to request cluster info, will try again: [Get https://192.168.0.101:6443/api/v1/namespaces/kube-public/configmaps/cluster-info: x509: certificate has expired or is not yet valid]
