使用kubeadm搭建高可用的K8s集群

今天药忘吃喽~ 2023-01-13 10:41 131阅读 0赞

kubeadm是官方社区推出的一个用于快速部署kubernetes集群的工具。

这个工具能通过两条指令完成一个kubernetes集群的部署：

# 创建一个 Master 节点
    $ kubeadm init
    
    # 将一个 Node 节点加入到当前集群中
    $ kubeadm join <Master节点的IP和端口 >

## 1. 安装要求 ##

在开始之前，部署Kubernetes集群机器需要满足以下几个条件：

*  一台或多台机器，操作系统 CentOS7.x-86\_x64
 *  硬件配置：2GB或更多RAM，2个CPU或更多CPU，硬盘30GB或更多
 *  可以访问外网，需要拉取镜像，如果服务器不能上网，需要提前下载镜像并导入节点
 *  禁止swap分区

## 2. 准备环境 ##

<table> 
 <thead> 
  <tr> 
   <th>角色</th> 
   <th>IP</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>master1</td> 
   <td>192.168.44.155</td> 
  </tr> 
  <tr> 
   <td>master2</td> 
   <td>192.168.44.156</td> 
  </tr> 
  <tr> 
   <td>node1</td> 
   <td>192.168.44.157</td> 
  </tr> 
  <tr> 
   <td>VIP（虚拟ip）</td> 
   <td>192.168.44.158</td> 
  </tr> 
 </tbody> 
</table>

# 关闭防火墙
    systemctl stop firewalld
    systemctl disable firewalld
    
    # 关闭selinux
    sed -i 's/enforcing/disabled/' /etc/selinux/config  # 永久
    setenforce 0  # 临时
    
    # 关闭swap
    swapoff -a  # 临时
    sed -ri 's/.*swap.*/#&/' /etc/fstab    # 永久
    
    # 根据规划设置主机名
    hostnamectl set-hostname <hostname>
    
    # 在master添加hosts
    cat >> /etc/hosts << EOF
    192.168.44.158    master.k8s.io   k8s-vip
    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
    cat > /etc/sysctl.d/k8s.conf << EOF
    net.bridge.bridge-nf-call-ip6tables = 1
    net.bridge.bridge-nf-call-iptables = 1
    EOF
    sysctl --system  # 生效
    
    # 时间同步
    yum install ntpdate -y
    ntpdate time.windows.com

## 3. 所有master节点部署keepalived ##

### 3.1 安装相关包和keepalived ###

yum install -y conntrack-tools libseccomp libtool-ltdl
    
    yum install -y keepalived

### 3.2配置master节点 ###

master1节点配置

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

master2节点配置

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

### 3.3 启动和检查 ###

在两台master节点都执行

# 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master1的网卡信息

ip a s ens33

## 4. 部署haproxy ##

### 4.1 安装 ###

yum install -y haproxy

### 4.2 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

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

### 4.3 启动和检查 ###

两台master都启动

# 设置开机启动
    $ systemctl enable haproxy
    # 开启haproxy
    $ systemctl start haproxy
    # 查看启动状态
    $ systemctl status haproxy

检查端口

netstat -lntup|grep haproxy

## 5. 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。

### 5.1 安装Docker ###

$ wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo
    $ yum -y install docker-ce-18.06.1.ce-3.el7
    $ systemctl enable docker && systemctl start docker
    $ docker --version
    Docker version 18.06.1-ce, build e68fc7a

$ cat > /etc/docker/daemon.json << EOF
    {
      "registry-mirrors": ["https://b9pmyelo.mirror.aliyuncs.com"]
    }
    EOF

### 5.2 添加阿里云YUM软件源 ###

$ 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

### 5.3 安装kubeadm，kubelet和kubectl ###

由于版本更新频繁，这里指定版本号部署：

$ yum install -y kubelet-1.16.3 kubeadm-1.16.3 kubectl-1.16.3
    $ systemctl enable kubelet

## 6. 部署Kubernetes Master ##

### 6.1 创建kubeadm配置文件 ###

在具有vip的master上操作，这里为master1

$ mkdir /usr/local/kubernetes/manifests -p
    
    $ cd /usr/local/kubernetes/manifests/
    
    $ vi kubeadm-config.yaml
    
    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: {}

### 6.2 在master1节点执行 ###

$ kubeadm init --config kubeadm-config.yaml

按照提示配置环境变量，使用kubectl工具：

mkdir -p $HOME/.kube
    sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
    sudo chown $(id -u):$(id -g) $HOME/.kube/config
    $ kubectl get nodes
    $ kubectl get pods -n kube-system

**按照提示保存以下内容，一会要使用：**

kubeadm join master.k8s.io:16443 --token jv5z7n.3y1zi95p952y9p65 \
        --discovery-token-ca-cert-hash sha256:403bca185c2f3a4791685013499e7ce58f9848e2213e27194b75a2e3293d8812 \
        --control-plane

查看集群状态

kubectl get cs
    
    kubectl get pods -n kube-system

## 7.安装集群网络 ##

从官方地址获取到flannel的yaml，在master1上执行

mkdir flannel
    cd flannel
    wget -c https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

安装flannel网络

kubectl apply -f kube-flannel.yml

检查

kubectl get pods -n kube-system

## 8、master2节点加入集群 ##

### 8.1 复制密钥及相关文件 ###

从master1复制密钥及相关文件到master2

# 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

### 8.2 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

kubeadm join master.k8s.io:16443 --token ckf7bs.30576l0okocepg8b     --discovery-token-ca-cert-hash sha256:19afac8b11182f61073e254fb57b9f19ab4d798b70501036fc69ebef46094aba --control-plane

检查状态

kubectl get node
    
    kubectl get pods --all-namespaces

##  ##

## 5. 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：

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

kubectl get node
    
    kubectl get pods --all-namespaces

##  ##

## 7. 测试kubernetes集群 ##

在Kubernetes集群中创建一个pod，验证是否正常运行：

$ kubectl create deployment nginx --image=nginx
    $ kubectl expose deployment nginx --port=80 --type=NodePort
    $ kubectl get pod,svc

访问地址：http://NodeIP:Port