k8s-高可用集群实现（keepalived）

一 环境规划

大致拓扑：

我这里是etcd和master都在同一台机器上面

二 系统初始化

见 https://www.cnblogs.com/huningfei/p/12697310.html

三 安装k8s和docker

见 https://www.cnblogs.com/huningfei/p/12697310.html

四 安装keepalived

在三台master节点上安装

yum -y install keepalived

配置文件
master1

[root@k8s-master01 keepalived]# cat keepalived.conf
! Configuration File for keepalived
global_defs {
   router_id master01
}
vrrp_instance VI_1 {
    state MASTER #主
    interface ens33 #网卡名字
    virtual_router_id 50
    priority 100 #权重
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.1.222 #vip
    }
}

master2

! Configuration File for keepalived
global_defs {
   router_id master01
}
vrrp_instance VI_1 {
    state BACKUP 
    interface ens32
    virtual_router_id 50
    priority 90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.1.222
    }
}

master3

! Configuration File for keepalived
global_defs {
   router_id master01
}
vrrp_instance VI_1 {
    state BACKUP 
    interface ens32
    virtual_router_id 50
    priority 80
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.1.222
    }
}

启动，并设置开机启动

service keepalived start
 systemctl enable keepalived

四初始化master节点

只在任意一台执行即可

kubeadm init --config=kubeadm-config.yaml
初始化配置文件如下：
```bash
[root@k8s-master01 load-k8s]# cat kubeadm-config.yaml
apiVersion: kubeadm.k8s.io/v1beta2
kind: ClusterConfiguration
kubernetesVersion: v1.15.1
apiServer:
  certSANs:    #填写所有kube-apiserver节点的hostname、IP、VIP(好像也可以不用写，只写vip就行)
  - k8s-master01
  - k8s-node1
  - k8s-node2
  - 192.168.1.210
  - 192.168.1.200
  - 192.168.1.211
  - 192.168.1.222
controlPlaneEndpoint: "192.168.1.222:6443" #vip
imageRepository: registry.aliyuncs.com/google_containers

networking:
  podSubnet: "10.244.0.0/16"
  serviceSubnet: 10.96.0.0/12

---
apiVersion: kubeproxy.config.k8s.io/v1alpha1
kind: KubeProxyConfiguration
featureGates:
  SupportIPVSProxyMode: true
mode: ipvs

出现图中信息代表初始化成功：

然后按照提示运行命令：

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

五安装网络插件flannel

kubectl apply -f kube-flannel.yml

六拷贝证书（关键步骤）

从master01上拷贝到其余两个主节点，我这里利用脚本拷贝

[root@k8s-master01 load-k8s]# cat cert-master.sh 
USER=root # customizable
CONTROL_PLANE_IPS="192.168.1.200 192.168.1.211"
for host in ${CONTROL_PLANE_IPS}; do
    scp /etc/kubernetes/pki/ca.crt "${USER}"@$host:
    scp /etc/kubernetes/pki/ca.key "${USER}"@$host:
    scp /etc/kubernetes/pki/sa.key "${USER}"@$host:
    scp /etc/kubernetes/pki/sa.pub "${USER}"@$host:
    scp /etc/kubernetes/pki/front-proxy-ca.crt "${USER}"@$host:
    scp /etc/kubernetes/pki/front-proxy-ca.key "${USER}"@$host:
    scp /etc/kubernetes/pki/etcd/ca.crt "${USER}"@$host:etcd-ca.crt
    # Quote this line if you are using external etcd
    scp /etc/kubernetes/pki/etcd/ca.key "${USER}"@$host:etcd-ca.key
done

然后去其他两个master节点把证书移动到/etc/kubernetes/pki目录下面，我这里用脚本移动
```bash
[root@k8s-node1 load-k8s]# cat mv-cert.sh 
USER=root # customizable
mkdir -p /etc/kubernetes/pki/etcd
mv /${USER}/ca.crt /etc/kubernetes/pki/
mv /${USER}/ca.key /etc/kubernetes/pki/
mv /${USER}/sa.pub /etc/kubernetes/pki/
mv /${USER}/sa.key /etc/kubernetes/pki/
mv /${USER}/front-proxy-ca.crt /etc/kubernetes/pki/
mv /${USER}/front-proxy-ca.key /etc/kubernetes/pki/
mv /${USER}/etcd-ca.crt /etc/kubernetes/pki/etcd/ca.crt
# Quote this line if you are using external etcd
mv /${USER}/etcd-ca.key /etc/kubernetes/pki/etcd/ca.key

七 剩余两个master节点加入集群

kubeadm join 192.168.1.222:6443 --token zi3lku.0jmskzstc49429cu 
    --discovery-token-ca-cert-hash sha256:75c2e15f51e23490a0b042d72d6ac84fc18ba63c230f27882728f8832711710b 
    --control-plane

注意这里的ip就是keepalived生成的虚拟ip
出现下面这个代表成功

加入成功之后，可以去三台master上面查看状态都是否成功
kubectl get nodes
说明：我这里的主机名由于省事，所以就没改成master主机名，其实三台都是master节点

八 node节点加入集群

kubeadm join 192.168.1.222:6443 --token zi3lku.0jmskzstc49429cu 
    --discovery-token-ca-cert-hash sha256:75c2e15f51e23490a0b042d72d6ac84fc18ba63c230f27882728f8832711710b

出现如下信息代表成功

查看节点状态，node3是我的node节点，其余都是主节点

九 集群高可用测试

1 master01关机，vip飘到了master02上面，各项功能正常
2 master02关机，vip飘到了master03上面，已有pod正常，但是所有命令都不能使用了
结论就是当坏掉其中一台master的时候，集群是可以正常工作的