kubeadm安装
安装环境（vm6.5下虚拟机3台，centos 7.4）：
master：10.20.0.191
Node1：10.20.0.192
Node2：10.20.0.193
1.安装虚拟机，配置网络接口；
2.修改主机名
hostnamectl set-hostname k8s-master
3.安装常用工具
yum install wget -y
yum install net-tools -y
yum install vim -y
4.配置yum源环境（是用阿里云镜像）
docker-ce
/etc/yum.repos.d目录下
wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
kubernetes
/etc/yum.repos.d目录下
vim kubenetes.repo
[root@k8s-master yum.repos.d]# cat kubenetes.repo
[kubernetes]
name=Kubernetes Repo
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
gpgcheck=1 #开启gpg校验
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg
enabled=1
yum repolist 检测yum源列表
5.gpg校验配置
下载校验文件
wget https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
wget https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg
导入校验文件
rpm --import rpm-package-key.gpg
rpm --import yum-key.gpg
6.关闭firewall，修改内核参数
systemctl disable firewalld
systemctl stop firewalld
vim /etc/sysctl.d/k8s.conf
添加如下内容
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
执行命令生效
modprobe br_netfilter
sysctl -p /etc/sysctl.d/k8s.conf
禁用节点上的swap
swapoff -a
sysctl -p
vim /ets/fstab #去除该文件中关于swap那行
7.安装docker-ce，kubelet组件
master节点安装
yum install docker-ce kubelet kubeadm kubectl
node节点安装
yum install docker-ce kubelet kubeadm
8.启动docker，kubelet
编辑kubelet的配置文件/etc/sysconfig/kubelet，设置其忽略Swap启用的状态错误，内容如下: KUBELET_EXTRA_ARGS=“—fail-swap-on=false” ,master以及node节点均需设置；
[root@k8s-master yum.repos.d]# cat /etc/sysconfig/kubelet
KUBELET_EXTRA_ARGS="--fail-swap-on=false"
google的镜像仓库k8s.grc.io国内无法访问，如有代理服务器，则编辑docker.service文件，添加代理服务器
vim /usr/lib/systemd/system/docker.service
添加如下内容
Environment="HTTPS_PROXY=https://[proxy-addr]:[proxy-port]/"
保存退出，从新加载配置文件，重启docker
systemctl daemon-reload
systemctl restart docker
启动docker，kubelet
systemctl enable docker kubelet
systemctl start docker
无代理服务，可以把k8s的软件包下载到本地安装，通过（docker load）命令加载tar包；
9.初始化master节点,node节点
master节点需要pull完成的相关镜像
k8s.gcr.io/kube-proxy v1.13.3 98db19758ad4 2 weeks ago 80.3MB
k8s.gcr.io/kube-apiserver v1.13.3 fe242e556a99 2 weeks ago 181MB
k8s.gcr.io/kube-controller-manager v1.13.3 0482f6400933 2 weeks ago 146MB
k8s.gcr.io/kube-scheduler v1.13.3 3a6f709e97a0 2 weeks ago 79.6MB
k8s.gcr.io/coredns 1.2.6 f59dcacceff4 3 months ago 40MB
k8s.gcr.io/etcd 3.2.24 3cab8e1b9802 5 months ago 220MB
k8s.gcr.io/pause 3.1 da86e6ba6ca1 14 months ago 742kB
quay.io/coreos/flannel v0.11.0-amd64 ff281650a721 2 weeks ago 52.6MB
node节点需要pull完成的相关镜像
k8s.gcr.io/kube-proxy v1.13.3 98db19758ad4 2 weeks ago 80.3MB
k8s.gcr.io/pause 3.1 da86e6ba6ca1 14 months ago 742kB
quay.io/coreos/flannel v0.11.0-amd64 ff281650a721 2 weeks ago 52.6MB
目前默认版本为1.13.3
kubeadm init --help 查看启动参数 默认监听端口6443
kubeadm init --kubernetes-version=v1.13.3 --pod-network-cidr=10.244.0.0/16 service-
cidr=10.96.0.0/12 --ignore-preflight-errors=Swap
启动完成后会显示join命令，记得保存
根据提示完成非root用户配置
mkdir ~/.kube
cp /etc/kubernetes/admin.conf ~/.kube/
chown $(id -u):$(id -g) $HOME/.kube/config
检查启动情况(nodes此时还只有master节点，未安装flannel时候状态不是ready)
[root@k8s-master yum.repos.d]# kubectl get componentstatus
NAME STATUS MESSAGE ERROR
scheduler Healthy ok
controller-manager Healthy ok
etcd-0 Healthy {"health": "true"}
[root@k8s-master yum.repos.d]# kubectl get nodes
NAME STATUS ROLES AGE VERSION
k8s-master Ready master 137m v1.13.3
k8s-node1 Ready <none> 72m v1.13.3
k8s-node2 Ready <none> 59m v1.13.3
10.安装flannel组件
coredns依赖flannel组件，未安装flannel时候查看coredns的状态为prending
[root@k8s-master yum.repos.d]# kubectl get pods -n kube-system -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
coredns-86c58d9df4-697md 1/1 Running 0 141m 10.244.0.2 k8s-master <none> <none>
coredns-86c58d9df4-7ppx6 1/1 Running 0 141m 10.244.0.3 k8s-master <none> <none>
etcd-k8s-master 1/1 Running 0 140m 10.20.0.191 k8s-master <none> <none>
kube-apiserver-k8s-master 1/1 Running 0 140m 10.20.0.191 k8s-master <none> <none>
kube-controller-manager-k8s-master 1/1 Running 0 140m 10.20.0.191 k8s-master <none> <none>
kube-flannel-ds-amd64-jnr54 1/1 Running 0 108m 10.20.0.191 k8s-master <none> <none>
kube-flannel-ds-amd64-n9c74 1/1 Running 0 64m 10.20.0.193 k8s-node2 <none> <none>
kube-flannel-ds-amd64-x7tj8 1/1 Running 0 77m 10.20.0.192 k8s-node1 <none> <none>
kube-proxy-8cvq4 1/1 Running 0 77m 10.20.0.192 k8s-node1 <none> <none>
kube-proxy-kc6bb 1/1 Running 0 64m 10.20.0.193 k8s-node2 <none> <none>
kube-proxy-rcfrt 1/1 Running 0 141m 10.20.0.191 k8s-master <none> <none>
kube-scheduler-k8s-master 1/1 Running 0 141m 10.20.0.191 k8s-master <none> <none>
安装flannel
master节点
kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
正常会自动pull flannel镜像，如网络不稳定，可以手动pull
docker pull quay.io/coreos/flannel:v0.11.0-amd64
node节点在加入k8s之后会自动pull flannel镜像，无需额外配置；
11.node节点加入k8s
kubeadm join 10.20.0.191:6443 --token qpibgq.aj47u2bq7l7w898x --discovery-token-ca-cert-hash sha256:868e795381864a9234e2a29f96cd6095831e8775a80a1f2c81319569cb876ff4 --ignore-preflight-errors=Swap
查看状态
[root@k8s-master yum.repos.d]# kubectl get nodes
NAME STATUS ROLES AGE VERSION
k8s-master Ready master 144m v1.13.3
k8s-node1 Ready <none> 79m v1.13.3
k8s-node2 Ready <none> 66m v1.13.3