# Kubernetes搭建高可用集群 ## 前言 之前我们搭建的集群，只有一个master节点，当master节点宕机的时候，通过node将无法继续访问，而master主要是管理作用，所以整个集群将无法提供服务  ## 高可用集群 下面我们就需要搭建一个多master节点的高可用集群，不会存在单点故障问题 但是在node 和 master节点之间，需要存在一个 LoadBalancer组件，作用如下： - 负载 - 检查master节点的状态  对外有一个统一的VIP：虚拟ip来对外进行访问 ## 高可用集群技术细节 高可用集群技术细节如下所示：  - keepalived：配置虚拟ip，检查节点的状态 - haproxy：负载均衡服务【类似于nginx】 - apiserver： - controller： - manager： - scheduler： ## 高可用集群步骤 我们采用2个master节点，一个node节点来搭建高可用集群，下面给出了每个节点需要做的事情  ## 初始化操作 我们需要在这三个节点上进行操作 ```bash # 关闭防火墙 systemctl stop firewalld systemctl disable firewalld # 关闭selinux # 永久关闭 sed -i 's/enforcing/disabled/' /etc/selinux/config # 临时关闭 setenforce 0 # 关闭swap # 临时 swapoff -a # 永久关闭 sed -ri 's/.*swap.*/#&/' /etc/fstab # 根据规划设置主机名【master1节点上操作】 hostnamectl set-hostname master1 # 根据规划设置主机名【master2节点上操作】 hostnamectl set-hostname master1 # 根据规划设置主机名【node1节点操作】 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 # 将桥接的IPv4流量传递到iptables的链【3个节点上都执行】 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 # 时间同步 yum install ntpdate -y ntpdate time.windows.com ``` ## 部署keepAlived 下面我们需要在所有的master节点【master1和master2】上部署keepAlive ### 安装相关包 ```bash # 安装相关工具 yum install -y conntrack-tools libseccomp libtool-ltdl # 安装keepalived yum install -y keepalived ``` ### 配置master节点 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 ``` ### 启动和检查 在两台master节点都执行 ```bash # 启动keepalived systemctl start keepalived.service # 设置开机启动 systemctl enable keepalived.service # 查看启动状态 systemctl status keepalived.service ``` 启动后查看master的网卡信息 ```bash ip a s ens33 ```  ## 部署haproxy haproxy主要做负载的作用，将我们的请求分担到不同的node节点上 ### 安装 在两个master节点安装 haproxy ```bash # 安装haproxy yum install -y haproxy # 启动 haproxy systemctl start haproxy # 开启自启 systemctl enable haproxy ``` 启动后，我们查看对应的端口是否包含 16443 ```bash netstat -tunlp | grep haproxy ```  ### 配置 两台master节点的配置均相同，配置中声明了后端代理的两个master节点服务器，指定了haproxy运行的端口为16443等，因此16443端口为集群的入口 ```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 ``` ## 安装Docker、Kubeadm、kubectl 所有节点安装Docker/kubeadm/kubelet ，Kubernetes默认CRI（容器运行时）为Docker，因此先安装Docker ### 安装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方式安装docker ```bash # yum安装 yum -y install docker-ce # 查看docker版本 docker --version # 启动docker systemctl enable docker systemctl start docker ``` 配置docker的镜像源 ```bash cat >> /etc/docker/daemon.json << EOF { "registry-mirrors": ["https://b9pmyelo.mirror.aliyuncs.com"] } EOF ``` 然后重启docker ```bash systemctl restart docker ``` ### 添加kubernetes软件源 然后我们还需要配置一下yum的k8s软件源 ```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 ``` ### 安装kubeadm，kubelet和kubectl 由于版本更新频繁，这里指定版本号部署： ```bash # 安装kubelet、kubeadm、kubectl，同时指定版本 yum install -y kubelet-1.18.0 kubeadm-1.18.0 kubectl-1.18.0 # 设置开机启动 systemctl enable kubelet ``` ## 部署Kubernetes Master【master节点】 ### 创建kubeadm配置文件 在具有vip的master上进行初始化操作，这里为master1 ```bash # 创建文件夹 mkdir /usr/local/kubernetes/manifests -p # 到manifests目录 cd /usr/local/kubernetes/manifests/ # 新建yaml文件 vi kubeadm-config.yaml ``` yaml内容如下所示： ```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: {} ``` 然后我们在 master1 节点执行 ```bash kubeadm init --config kubeadm-config.yaml ``` 执行完成后，就会在拉取我们的进行了【需要等待...】  按照提示配置环境变量，使用kubectl工具 ```bash # 执行下方命令 mkdir -p $HOME/.kube sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config sudo chown $(id -u):$(id -g) $HOME/.kube/config # 查看节点 kubectl get nodes # 查看pod kubectl get pods -n kube-system ``` **按照提示保存以下内容，一会要使用：** ```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节点的时候才有 查看集群状态 ```bash # 查看集群状态 kubectl get cs # 查看pod kubectl get pods -n kube-system ``` ## 安装集群网络 从官方地址获取到flannel的yaml，在master1上执行 ```bash # 创建文件夹 mkdir flannel cd flannel # 下载yaml文件 wget -c https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml ``` 安装flannel网络 ```bash kubectl apply -f kube-flannel.yml ``` 检查 ```bash kubectl get pods -n kube-system ``` ## master2节点加入集群 ### 复制密钥及相关文件 从master1复制密钥及相关文件到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 执行在master1上init后输出的join命令,需要带上参数`--control-plane`表示把master控制节点加入集群 ```bash kubeadm join master.k8s.io:16443 --token ckf7bs.30576l0okocepg8b --discovery-token-ca-cert-hash sha256:19afac8b11182f61073e254fb57b9f19ab4d798b70501036fc69ebef46094aba --control-plane ``` 检查状态 ```bash kubectl get node kubectl get pods --all-namespaces ``` ## 加入Kubernetes Node 在node1上执行 向集群添加新节点，执行在kubeadm init输出的kubeadm join命令： ```bash kubeadm join master.k8s.io:16443 --token ckf7bs.30576l0okocepg8b --discovery-token-ca-cert-hash sha256:19afac8b11182f61073e254fb57b9f19ab4d798b70501036fc69ebef46094aba ``` **集群网络重新安装，因为添加了新的node节点** 检查状态 ```bash kubectl get node kubectl get pods --all-namespaces ``` ## 测试kubernetes集群 在Kubernetes集群中创建一个pod，验证是否正常运行： ```bash # 创建nginx deployment kubectl create deployment nginx --image=nginx # 暴露端口 kubectl expose deployment nginx --port=80 --type=NodePort # 查看状态 kubectl get pod,svc ``` 然后我们通过任何一个节点，都能够访问我们的nginx页面