# Kubernetes搭建高可用集群 ## 前言 之前我們搭建的集群，只有一個master節點，當master節點宕機的時候，通過node將無法繼續訪問，而master主要是管理作用，所以整個集群將無法提供服務  ## 高可用集群 下面我們就需要搭建一個多master節點的高可用集群，不會存在單點故障問題 但是在node 和 master節點之間，需要存在一個 LoadBalancer組件，作用如下： - 負載 - 檢查master節點的狀態  對外有一個統一的VIP：虛擬ip來對外進行訪問 ## 高可用集群技術細節 高可用集群技術細節如下所示：  - keepalived：配置虛擬ip，檢查節點的狀態 - haproxy：負載均衡服務【類似于nginx】 - apiserver： - controller： - manager： - scheduler： ## 高可用集群步驟 我們采用2個master節點，一個node節點來搭建高可用集群，下面給出了每個節點需要做的事情  ## 初始化操作 我們需要在這三個節點上進行操作 ```bash # 關閉防火墻 systemctl stop firewalld systemctl disable firewalld # 關閉selinux # 永久關閉 sed -i 's/enforcing/disabled/' /etc/selinux/config # 臨時關閉 setenforce 0 # 關閉swap # 臨時 swapoff -a # 永久關閉 sed -ri 's/.*swap.*/#&/' /etc/fstab # 根據規劃設置主機名【master1節點上操作】 hostnamectl set-hostname master1 # 根據規劃設置主機名【master2節點上操作】 hostnamectl set-hostname master1 # 根據規劃設置主機名【node1節點操作】 hostnamectl set-hostname node1 # r添加hosts cat >> /etc/hosts << EOF 192.168.44.158 k8smaster 192.168.44.155 master01.k8s.io master1 192.168.44.156 master02.k8s.io master2 192.168.44.157 node01.k8s.io node1 EOF # 將橋接的IPv4流量傳遞到iptables的鏈【3個節點上都執行】 cat > /etc/sysctl.d/k8s.conf << EOF net.bridge.bridge-nf-call-ip6tables = 1 net.bridge.bridge-nf-call-iptables = 1 EOF # 生效 sysctl --system # 時間同步 yum install ntpdate -y ntpdate time.windows.com ``` ## 部署keepAlived 下面我們需要在所有的master節點【master1和master2】上部署keepAlive ### 安裝相關包 ```bash # 安裝相關工具 yum install -y conntrack-tools libseccomp libtool-ltdl # 安裝keepalived yum install -y keepalived ``` ### 配置master節點 添加master1的配置 ```bash cat > /etc/keepalived/keepalived.conf <<EOF ! Configuration File for keepalived global_defs { router_id k8s } vrrp_script check_haproxy { script "killall -0 haproxy" interval 3 weight -2 fall 10 rise 2 } vrrp_instance VI_1 { state MASTER interface ens33 virtual_router_id 51 priority 250 advert_int 1 authentication { auth_type PASS auth_pass ceb1b3ec013d66163d6ab } virtual_ipaddress { 192.168.44.158 } track_script { check_haproxy } } EOF ``` 添加master2的配置 ```bash cat > /etc/keepalived/keepalived.conf <<EOF ! Configuration File for keepalived global_defs { router_id k8s } vrrp_script check_haproxy { script "killall -0 haproxy" interval 3 weight -2 fall 10 rise 2 } vrrp_instance VI_1 { state BACKUP interface ens33 virtual_router_id 51 priority 200 advert_int 1 authentication { auth_type PASS auth_pass ceb1b3ec013d66163d6ab } virtual_ipaddress { 192.168.44.158 } track_script { check_haproxy } } EOF ``` ### 啟動和檢查 在兩臺master節點都執行 ```bash # 啟動keepalived systemctl start keepalived.service # 設置開機啟動 systemctl enable keepalived.service # 查看啟動狀態 systemctl status keepalived.service ``` 啟動后查看master的網卡信息 ```bash ip a s ens33 ```  ## 部署haproxy haproxy主要做負載的作用，將我們的請求分擔到不同的node節點上 ### 安裝 在兩個master節點安裝 haproxy ```bash # 安裝haproxy yum install -y haproxy # 啟動 haproxy systemctl start haproxy # 開啟自啟 systemctl enable haproxy ``` 啟動后，我們查看對應的端口是否包含 16443 ```bash netstat -tunlp | grep haproxy ```  ### 配置 兩臺master節點的配置均相同，配置中聲明了后端代理的兩個master節點服務器，指定了haproxy運行的端口為16443等，因此16443端口為集群的入口 ```bash cat > /etc/haproxy/haproxy.cfg << EOF #--------------------------------------------------------------------- # Global settings #--------------------------------------------------------------------- global # to have these messages end up in /var/log/haproxy.log you will # need to: # 1) configure syslog to accept network log events. This is done # by adding the '-r' option to the SYSLOGD_OPTIONS in # /etc/sysconfig/syslog # 2) configure local2 events to go to the /var/log/haproxy.log # file. A line like the following can be added to # /etc/sysconfig/syslog # # local2.* /var/log/haproxy.log # log 127.0.0.1 local2 chroot /var/lib/haproxy pidfile /var/run/haproxy.pid maxconn 4000 user haproxy group haproxy daemon # turn on stats unix socket stats socket /var/lib/haproxy/stats #--------------------------------------------------------------------- # common defaults that all the 'listen' and 'backend' sections will # use if not designated in their block #--------------------------------------------------------------------- defaults mode http log global option httplog option dontlognull option http-server-close option forwardfor except 127.0.0.0/8 option redispatch retries 3 timeout http-request 10s timeout queue 1m timeout connect 10s timeout client 1m timeout server 1m timeout http-keep-alive 10s timeout check 10s maxconn 3000 #--------------------------------------------------------------------- # kubernetes apiserver frontend which proxys to the backends #--------------------------------------------------------------------- frontend kubernetes-apiserver mode tcp bind *:16443 option tcplog default_backend kubernetes-apiserver #--------------------------------------------------------------------- # round robin balancing between the various backends #--------------------------------------------------------------------- backend kubernetes-apiserver mode tcp balance roundrobin server master01.k8s.io 192.168.44.155:6443 check server master02.k8s.io 192.168.44.156:6443 check #--------------------------------------------------------------------- # collection haproxy statistics message #--------------------------------------------------------------------- listen stats bind *:1080 stats auth admin:awesomePassword stats refresh 5s stats realm HAProxy\ Statistics stats uri /admin?stats EOF ``` ## 安裝Docker、Kubeadm、kubectl 所有節點安裝Docker/kubeadm/kubelet ，Kubernetes默認CRI（容器運行時）為Docker，因此先安裝Docker ### 安裝Docker 首先配置一下Docker的阿里yum源 ```bash cat >/etc/yum.repos.d/docker.repo<<EOF [docker-ce-edge] name=Docker CE Edge - \$basearch baseurl=https://mirrors.aliyun.com/docker-ce/linux/centos/7/\$basearch/edge enabled=1 gpgcheck=1 gpgkey=https://mirrors.aliyun.com/docker-ce/linux/centos/gpg EOF ``` 然后yum方式安裝docker ```bash # yum安裝 yum -y install docker-ce # 查看docker版本 docker --version # 啟動docker systemctl enable docker systemctl start docker ``` 配置docker的鏡像源 ```bash cat >> /etc/docker/daemon.json << EOF { "registry-mirrors": ["https://b9pmyelo.mirror.aliyuncs.com"] } EOF ``` 然后重啟docker ```bash systemctl restart docker ``` ### 添加kubernetes軟件源 然后我們還需要配置一下yum的k8s軟件源 ```bash cat > /etc/yum.repos.d/kubernetes.repo << EOF [kubernetes] name=Kubernetes baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64 enabled=1 gpgcheck=0 repo_gpgcheck=0 gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg EOF ``` ### 安裝kubeadm，kubelet和kubectl 由于版本更新頻繁，這里指定版本號部署： ```bash # 安裝kubelet、kubeadm、kubectl，同時指定版本 yum install -y kubelet-1.18.0 kubeadm-1.18.0 kubectl-1.18.0 # 設置開機啟動 systemctl enable kubelet ``` ## 部署Kubernetes Master【master節點】 ### 創建kubeadm配置文件 在具有vip的master上進行初始化操作，這里為master1 ```bash # 創建文件夾 mkdir /usr/local/kubernetes/manifests -p # 到manifests目錄 cd /usr/local/kubernetes/manifests/ # 新建yaml文件 vi kubeadm-config.yaml ``` yaml內容如下所示： ```bash apiServer: certSANs: - master1 - master2 - master.k8s.io - 192.168.44.158 - 192.168.44.155 - 192.168.44.156 - 127.0.0.1 extraArgs: authorization-mode: Node,RBAC timeoutForControlPlane: 4m0s apiVersion: kubeadm.k8s.io/v1beta1 certificatesDir: /etc/kubernetes/pki clusterName: kubernetes controlPlaneEndpoint: "master.k8s.io:16443" controllerManager: {} dns: type: CoreDNS etcd: local: dataDir: /var/lib/etcd imageRepository: registry.aliyuncs.com/google_containers kind: ClusterConfiguration kubernetesVersion: v1.16.3 networking: dnsDomain: cluster.local podSubnet: 10.244.0.0/16 serviceSubnet: 10.1.0.0/16 scheduler: {} ``` 然后我們在 master1 節點執行 ```bash kubeadm init --config kubeadm-config.yaml ``` 執行完成后，就會在拉取我們的進行了【需要等待...】  按照提示配置環境變量，使用kubectl工具 ```bash # 執行下方命令 mkdir -p $HOME/.kube sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config sudo chown $(id -u):$(id -g) $HOME/.kube/config # 查看節點 kubectl get nodes # 查看pod kubectl get pods -n kube-system ``` **按照提示保存以下內容，一會要使用：** ```bash kubeadm join master.k8s.io:16443 --token jv5z7n.3y1zi95p952y9p65 \ --discovery-token-ca-cert-hash sha256:403bca185c2f3a4791685013499e7ce58f9848e2213e27194b75a2e3293d8812 \ --control-plane ``` > --control-plane ： 只有在添加master節點的時候才有 查看集群狀態 ```bash # 查看集群狀態 kubectl get cs # 查看pod kubectl get pods -n kube-system ``` ## 安裝集群網絡 從官方地址獲取到flannel的yaml，在master1上執行 ```bash # 創建文件夾 mkdir flannel cd flannel # 下載yaml文件 wget -c https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml ``` 安裝flannel網絡 ```bash kubectl apply -f kube-flannel.yml ``` 檢查 ```bash kubectl get pods -n kube-system ``` ## master2節點加入集群 ### 復制密鑰及相關文件 從master1復制密鑰及相關文件到master2 ```bash # ssh root@192.168.44.156 mkdir -p /etc/kubernetes/pki/etcd # scp /etc/kubernetes/admin.conf root@192.168.44.156:/etc/kubernetes # scp /etc/kubernetes/pki/{ca.*,sa.*,front-proxy-ca.*} root@192.168.44.156:/etc/kubernetes/pki # scp /etc/kubernetes/pki/etcd/ca.* root@192.168.44.156:/etc/kubernetes/pki/etcd ``` ### master2加入集群 執行在master1上init后輸出的join命令,需要帶上參數`--control-plane`表示把master控制節點加入集群 ```bash kubeadm join master.k8s.io:16443 --token ckf7bs.30576l0okocepg8b --discovery-token-ca-cert-hash sha256:19afac8b11182f61073e254fb57b9f19ab4d798b70501036fc69ebef46094aba --control-plane ``` 檢查狀態 ```bash kubectl get node kubectl get pods --all-namespaces ``` ## 加入Kubernetes Node 在node1上執行 向集群添加新節點，執行在kubeadm init輸出的kubeadm join命令： ```bash kubeadm join master.k8s.io:16443 --token ckf7bs.30576l0okocepg8b --discovery-token-ca-cert-hash sha256:19afac8b11182f61073e254fb57b9f19ab4d798b70501036fc69ebef46094aba ``` **集群網絡重新安裝，因為添加了新的node節點** 檢查狀態 ```bash kubectl get node kubectl get pods --all-namespaces ``` ## 測試kubernetes集群 在Kubernetes集群中創建一個pod，驗證是否正常運行： ```bash # 創建nginx deployment kubectl create deployment nginx --image=nginx # 暴露端口 kubectl expose deployment nginx --port=80 --type=NodePort # 查看狀態 kubectl get pod,svc ``` 然后我們通過任何一個節點，都能夠訪問我們的nginx頁面