k8s-高可用集群實現（keepalived）

一 環境規划

大致拓撲：

我這里是etcd和master都在同一台機器上面

二 系統初始化

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

三 安裝k8s和docker

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

四 安裝keepalived

在三台master節點上安裝

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 #網卡名字
    virtual_router_id 50
    priority 100 #權重
    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
    }
}

啟動，並設置開機啟動

service keepalived start
 systemctl enable keepalived

四初始化master節點

只在任意一台執行即可

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:    #填寫所有kube-apiserver節點的hostname、IP、VIP(好像也可以不用寫，只寫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

出現圖中信息代表初始化成功：

然后按照提示運行命令：

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

五安裝網絡插件flannel

kubectl apply -f kube-flannel.yml

六拷貝證書（關鍵步驟）

從master01上拷貝到其余兩個主節點，我這里利用腳本拷貝

[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

然后去其他兩個master節點把證書移動到/etc/kubernetes/pki目錄下面，我這里用腳本移動
```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 剩余兩個master節點加入集群

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

注意這里的ip就是keepalived生成的虛擬ip
出現下面這個代表成功

加入成功之后，可以去三台master上面查看狀態都是否成功
kubectl get nodes
說明：我這里的主機名由於省事，所以就沒改成master主機名，其實三台都是master節點

八 node節點加入集群

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

出現如下信息代表成功

查看節點狀態，node3是我的node節點，其余都是主節點

九 集群高可用測試

1 master01關機，vip飄到了master02上面，各項功能正常
2 master02關機，vip飄到了master03上面，已有pod正常，但是所有命令都不能使用了
結論就是當壞掉其中一台master的時候，集群是可以正常工作的