使用kubeadm安装无疑是一种不错的选择。参考：https://www.cnblogs.com/benjamin77/p/9783797.html
1、环境准备
1.1系统配置
系统是CentOS Linux release 7.6
[root@k8s-master ~]# cat /etc/hosts 192.168.1.134 k8s-master 192.168.1.135 k8s-node1
192.168.1.136 k8s-node2
禁用防火墙和selinux
systemctl stop firewalld systemctl disable firewalld setenforce 0 sed -i "s/SELINUX=enforcing/SELINUX=disabled/g" /etc/selinux/config
关闭系统的Swap（Kubernetes 1.8开始要求）
swapoff -a yes | cp /etc/fstab /etc/fstab_bak cat /etc/fstab_bak |grep -v swap > /etc/fstab
添加内核参数文件 /etc/sysctl.d/k8s.conf
echo """
vm.swappiness = 0
net.ipv4.ip_forward = 1
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
""" > /etc/sysctl.conf
sysctl -p
执行命令使修改生效
modprobe br_netfilter sysctl -p /etc/sysctl.d/k8s.conf
同步时间
ntpdate -u ntp.api.bz
升级内核到最新（已准备内核离线安装包，可选）centos7 升级内核
所有机器需要设定/etc/sysctl.d/k8s.conf的系统参数
# https://github.com/moby/moby/issues/31208 # ipvsadm -l --timout # 修复ipvs模式下长连接timeout问题 小于900即可 cat <<EOF > /etc/sysctl.d/k8s.conf net.ipv4.tcp_keepalive_time = 600 net.ipv4.tcp_keepalive_intvl = 30 net.ipv4.tcp_keepalive_probes = 10 net.ipv6.conf.all.disable_ipv6 = 1 net.ipv6.conf.default.disable_ipv6 = 1 net.ipv6.conf.lo.disable_ipv6 = 1 net.ipv4.neigh.default.gc_stale_time = 120 net.ipv4.conf.all.rp_filter = 0 net.ipv4.conf.default.rp_filter = 0 net.ipv4.conf.default.arp_announce = 2 net.ipv4.conf.lo.arp_announce = 2 net.ipv4.conf.all.arp_announce = 2 net.ipv4.ip_forward = 1 net.ipv4.tcp_max_tw_buckets = 5000 net.ipv4.tcp_syncookies = 1 net.ipv4.tcp_max_syn_backlog = 1024 net.ipv4.tcp_synack_retries = 2 net.bridge.bridge-nf-call-ip6tables = 1 net.bridge.bridge-nf-call-iptables = 1 net.netfilter.nf_conntrack_max = 2310720 fs.inotify.max_user_watches=89100 fs.may_detach_mounts = 1 fs.file-max = 52706963 fs.nr_open = 52706963 net.bridge.bridge-nf-call-arptables = 1 vm.swappiness = 0 vm.overcommit_memory=1 vm.panic_on_oom=0 EOF sysctl --system
设置开机启动
# 启动docker sed -i "13i ExecStartPost=/usr/sbin/iptables -P FORWARD ACCEPT" /usr/lib/systemd/system/docker.service systemctl daemon-reload systemctl enable docker systemctl start docker # 设置kubelet开机启动 systemctl enable kubelet systemctl enable keepalived systemctl enable haproxy
设置免密登录
# 1、三次回车后，密钥生成完成 ssh-keygen # 2、拷贝密钥到其他节点 ssh-copy-id -i ~/.ssh/id_rsa.pub 用户名字@192.168.x.xxx
1.2安装Docker（所有节点）
yum install -y yum-utils device-mapper-persistent-data lvm2
wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker.repo
查看可下载的版本
[root@k8s-master ~]# yum list docker-ce.x86_64 --showduplicates |sort -r
# yum makecache fast
# yum install docker-ce -y
[root@k8s-node1 ~]# docker -v Docker version 18.06.1-ce, build e68fc7a
[root@k8s-node1 ~]#sed -i "13i ExecStartPost=/usr/sbin/iptables -P FORWARD ACCEPT" /usr/lib/systemd/system/docker.service
[root@k8s-node1 ~]# systemctl daemon-reload ;systemctl start docker ;systemctl enable docker
2.使用kubeadm部署Kubernetes
2.1安装kubelet 和 kubeadm
生成kubernetes的yum仓库配置文件/etc/yum.repos.d/kubernetes.repo，内容如下：(默认安装最新版本，我此时安装时版本为1.14.2)
[kubernetes] name=Kubernetes baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/ gpgcheck=0 gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg enabled=1
yum makecache fast yum install -y kubelet kubeadm kubectl
或者指定版本号：yum -y install kubelet-1.14.2-0.x86_64 kubeadm-1.14.2-0.x86_64 kubectl-1.14.2-0.x86_64
关闭swap功能
[root@k8s-node1 yum.repos.d]# swapoff -a [root@k8s-node1 yum.repos.d]# sysctl -p /etc/sysctl.d/k8s.conf
注释掉 、/etc/fstab 中swap的条目
mount -a
echo "KUBELET_EXTRA_ARGS=--fail-swap-on=false" > /etc/sysconfig/kubelet
2.2 使用kubeadm init初始化集群
在各节点开机启动kubelet服务：
systemctl enable kubelet.service
使用kubeadm初始化集群，会发生一下错误，这是由于初始化时，先从本地查找 有没有kubenetes组件的相关镜像如果找不到就从谷歌镜像站下载，如果你不FQ就只能让本地存在这些镜像。
我们可以从docker镜像站下载kubernetes相关组件的镜像然后给他重新打tag
[root@k8s-master ~]#kubeadm init --kubernetes-version=v1.14.2 --pod-network-cidr=10.244.0.0/16 --service-cidr=10.96.0.0/12 --apiserver-advertise-address=10.0.0.11 --ignore-preflight-errors=Swap
执行脚本
[root@k8s-master ~]# cat k8s.sh
docker pull mirrorgooglecontainers/kube-apiserver:v1.14.2
docker pull mirrorgooglecontainers/kube-controller-manager:v1.14.2
docker pull mirrorgooglecontainers/kube-scheduler:v1.14.2
docker pull mirrorgooglecontainers/kube-proxy:v1.14.2
docker pull mirrorgooglecontainers/pause:3.1
docker pull mirrorgooglecontainers/etcd:3.3.10
docker pull coredns/coredns:1.3.1
docker tag mirrorgooglecontainers/kube-proxy:v1.14.2 k8s.gcr.io/kube-proxy:v1.14.2
docker tag mirrorgooglecontainers/kube-scheduler:v1.14.2 k8s.gcr.io/kube-scheduler:v1.14.2
docker tag mirrorgooglecontainers/kube-apiserver:v1.14.2 k8s.gcr.io/kube-apiserver:v1.14.2
docker tag mirrorgooglecontainers/kube-controller-manager:v1.14.2 k8s.gcr.io/kube-controller-manager:v1.14.2
docker tag mirrorgooglecontainers/etcd:3.3.10 k8s.gcr.io/etcd:3.3.10
docker tag coredns/coredns:1.3.1 k8s.gcr.io/coredns:1.3.1
docker tag mirrorgooglecontainers/pause:3.1 k8s.gcr.io/pause:3.1
docker rmi mirrorgooglecontainers/kube-proxy:v1.14.2
docker rmi mirrorgooglecontainers/kube-scheduler:v1.14.2
docker rmi mirrorgooglecontainers/kube-apiserver:v1.14.2
docker rmi mirrorgooglecontainers/kube-controller-manager:v1.14.2
docker rmi mirrorgooglecontainers/etcd:3.3.10
docker rmi coredns/coredns:1.3.1
docker rmi mirrorgooglecontainers/pause:3.1
bash k8s.sh
[root@k8s-master ~]# docker images
具体操作如下：
查看kubernetes的版本
[root@k8s-master yum.repos.d]# kubeadm version
kubeadm version: &version.Info{Major:"1", Minor:"14", GitVersion:"v1.14.2", GitCommit:"4ed3216f3ec431b140b1d899130a69fc671678f4", GitTreeState:"clean", BuildDate:"2019-05-30T16:43:08Z", GoVersion:"go1.10.4", Compiler:"gc", Platform:"linux/amd64"}
再次在master节点上执行初始化
[root@k8s-master ~]#kubeadm init --kubernetes-version=v1.14.2 --pod-network-cidr=10.244.0.0/16 --service-cidr=10.96.0.0/12 --apiserver-advertise-address=10.0.0.11 --ignore-preflight-errors=Swap
输出信息如下：
[root@k8s-master ~]#kubeadm init --kubernetes-version=v1.14.2 --pod-network-cidr=10.244.0.0/16 --service-cidr=10.96.0.0/12 --apiserver-advertise-address=10.0.0.11 --ignore-preflight-errors=Swap
Your 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/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/
Then you can join any number of worker nodes by running the following on each as root:
kubeadm join 192.168.1.153:6443 --token il8ser.l9jyab9xa6m2t971
--discovery-token-ca-cert-hash sha256:492ec57cb9723ae8a71c2b9668bb7a86f0333c530ea5db10540882d6a6463efc
按照上面输出提示进行操作
[root@k8s-master ~]# mkdir -p $HOME/.kube [root@k8s-master ~]# sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config [root@k8s-master ~]# sudo chown $(id -u):$(id -g) $HOME/.kube/config
mkdir -p ~/k8s/ && cd ~/k8s
[root@k8s-master k8s]# wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
#这里改成自己的网卡
# vim kube-flannel.yml args: - --ip-masq - --kube-subnet-mgr - --iface=eth0 # kubectl apply -f kube-flannel.yml
查看集群状态
集群初始化如果遇到问题，可以使用下面的命令进行清理：
kubeadm reset ifconfig cni0 down ip link delete cni0 ifconfig flannel.1 down ip link delete flannel.1 rm -rf /var/lib/cni/
2.3 安装Pod Network
#这时master状态为notready 是因为没有网络插件
[root@k8s-master k8s]# kubectl get nodes NAME STATUS ROLES AGE VERSION k8s-master NotReady master 27m v1.12.1
接下来安装flannel network add-on：
获取组件健康状态
[root@k8s-master k8s]# kubectl get cs
NAME STATUS MESSAGE ERROR
scheduler Healthy ok
controller-manager Healthy ok
etcd-0 Healthy {"health": "true"}
[root@k8s-master k8s]# kubectl describe node k8s-master
Name: k8s-master
Roles: master
Labels: beta.kubernetes.io/arch=amd64
beta.kubernetes.io/os=linux
kubernetes.io/hostname=k8s-master
node-role.kubernetes.io/master=
Annotations: kubeadm.alpha.kubernetes.io/cri-socket: /var/run/dockershim.sock
node.alpha.kubernetes.io/ttl: 0
volumes.kubernetes.io/controller-managed-attach-detach: true
CreationTimestamp: Wed, 17 Oct 2018 21:24:01 +0800
Taints: node-role.kubernetes.io/master:NoSchedule
node.kubernetes.io/not-ready:NoSchedule
Unschedulable: false
上面输出显示首先会下载一个flannel镜像，namespace全部为running状态， master为ready
2.4master参与工作负载
出于安全考虑Pod不会被调度到Master Node上，也就是说Master Node不参与工作负载。这是因为当前的master节点node1被打上了node-role.kubernetes.io/master:NoSchedule的污点：
[root@k8s-master k8s]# kubectl describe node k8s-master | grep Taint Taints: node-role.kubernetes.io/master:NoSchedule
# 如果需要改回来不想让master节点参与到工作负载
kubectl taint node k8s-master node-role.kubernetes.io/master="":NoSchedule
去除污点使k8s-master参与负载
[root@k8s-master k8s]# kubectl taint nodes k8s-master node-role.kubernetes.io/master-
node/k8s-master untainted
[root@k8s-master k8s]# kubectl describe node k8s-master | grep Taint
Taints: <none>
2.5测试DNS
kubectl run curl --image=radial/busyboxplus:curl -it
2.6 向Kubernetes集群中添加Node节点
下面我们将node1 node2这个主机添加到Kubernetes集群中， 在node1和node2上执行:
[root@k8s-node1 ~]# kubeadm join 10.0.0.11:6443 --token i4us8x.pw2f3botcnipng8e --discovery-token-ca-cert-hash sha256:d16ac747c2312ae829aa29a3596f733f920ca3d372d9f1b34d33c938be067e51
查看节点，
原因是节点k8-node1也要获取镜像，执行以上的获取镜像的脚本即可，两个节点分别重置集群，kubeadm reset，然后重新初始化。
从master节点如果需要移出这个node1节点
在master节点上执行：
kubectl drain k8s-node1 --delete-local-data --force --ignore-daemonsets kubectl delete node k8s-node1
