【Kubernetes部署篇】Kubeadm方式搭建K8s高可用集群1.23.0版本

一、集群规划及架构

官方文档：

二进制下载地址

环境规划：

• pod网段：10.244.0.0/16

• service网段：10.10.0.0/16

• 注意： pod和service网段不可冲突，如果冲突会导致K8S集群安装失败。

主机名	IP地址	操作系统	备注
master-1	16.32.15.200	CentOS7.8	安装keepalived、nginx实现高可用
master-2	16.32.15.201	CentOS7.8	安装keepalived、nginx实现高可用
node-1	16.32.15.202	CentOS7.8
\	16.32.15.100	\	VIP地址

本次实验架构图：

二、系统初始化准备(所有节点同步操作)

1、关闭防火墙

systemctl disable firewalld --now
setenforce 0
sed  -i -r 's/SELINUX=[ep].*/SELINUX=disabled/g' /etc/selinux/config

2、配置域名解析

cat  >> /etc/hosts << EOF
16.32.15.200 master-1
16.32.15.201 master-2
16.32.15.202 node-1
EOF

在指定主机上面修改主机名

hostnamectl set-hostname master-1 && bash
hostnamectl set-hostname master-2 && bash
hostnamectl set-hostname node-1 && bash

3、配置服务器时间保持一致

yum -y install ntpdate
ntpdate ntp1.aliyun.com

添加定时同步 每天凌晨1点自动同步时间

echo "0 1 * * * ntpdate ntp1.aliyun.com" >> /var/spool/cron/root
crontab -l

4、禁用swap交换分区（kubernetes强制要求禁用）

swapoff --all

禁止开机自启动swap交换分区

sed -i -r '/swap/ s/^/#/' /etc/fstab

5、修改Linux内核参数，添加网桥过滤器和地址转发功能

cat >> /etc/sysctl.d/kubernetes.conf <<EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
EOF

sysctl -p /etc/sysctl.d/kubernetes.conf

加载网桥过滤器模块

modprobe br_netfilter
lsmod | grep br_netfilter # 验证是否生效

6、配置ipvs功能

在kubernetes中Service有两种代理模型，一种是基于iptables的，一种是基于ipvs，两者对比ipvs的性能要高，如果想要使用ipvs模型，需要手动载入ipvs模块

yum -y install ipset ipvsadm

cat > /etc/sysconfig/modules/ipvs.modules <<EOF
modprobe -- ip_vs
modprobe -- ip_vs_rr
modprobe -- ip_vs_wrr
modprobe -- ip_vs_sh
modprobe -- nf_conntrack_ipv4  
EOF

chmod +x /etc/sysconfig/modules/ipvs.modules 
# 执行脚本
/etc/sysconfig/modules/ipvs.modules

# 验证ipvs模块
lsmod | grep -e ip_vs -e nf_conntrack_ipv4

7、安装Docker容器组件

curl -o /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-7.repo
wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-7.repo
yum makecache

# yum-utils软件用于提供yum-config-manager程序
yum install -y yum-utils

# 使用yum-config-manager创建docker阿里存储库
yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo

yum install docker-ce-20.10.6 docker-ce-cli-20.10.6 -y

Docker默认使用的Cgroup Driver为默认文件驱动,而k8s默认使用的文件驱动为systemd,k8s要求驱动类型必须要一致,所以需要将docker文件驱动改成systemd,并且配置国内加速器。

mkdir /etc/docker
cat <<EOF > /etc/docker/daemon.json
{
  "registry-mirrors": ["https://aoewjvel.mirror.aliyuncs.com"],
  "exec-opts": ["native.cgroupdriver=systemd"]
}
EOF

# 启动docker并设置开机自启
systemctl enable docker --now
systemctl status docker

8、重启服务器 可略过

reboot

三、安装kubeadm(所有节点同步操作)

配置国内yum源，一键安装 kubeadm、kubelet、kubectl

cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
enabled=1
gpgcheck=0
EOF

yum -y install --setopt=obsoletes=0 kubeadm-1.23.0 kubelet-1.23.0 kubectl-1.23.0

kubeadm将使用kubelet服务以容器方式部署kubernetes的主要服务，所以需要先启动kubelet服务

systemctl enable kubelet.service --now

四、高可用组件安装及配置

master-1、master-2主机上进行操作

1、安装Nginx及配置

在 master-1、 master-2主机同步执行，Nginx配置是一致的

wget -O /etc/yum.repos.d/epel.repo https://mirrors.aliyun.com/repo/epel-7.repo
yum -y install nginx*

配置Nginx文件内容如下：如果主机名称一致，那么Nginx配置文件直接复制即可,如果主机名不一致则需要更改 upstream k8s-apiserver下面为对应的主机名或者IP地址。

mv /etc/nginx/nginx.conf{
    
    ,.bak}
cat >> /etc/nginx/nginx.conf << EOF

user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log;
pid /run/nginx.pid;

include /usr/share/nginx/modules/*.conf;

events {
    worker_connections 1024;
}

stream {

    log_format  main  '$remote_addr $upstream_addr - [$time_local] $status $upstream_bytes_sent';

    access_log  /var/log/nginx/k8s-access.log  main;

    upstream k8s-apiserver {
       server master-1:6443; 
       server master-2:6443;
    }

server {
       listen 16443; 
       proxy_pass k8s-apiserver;
    }
}


http {
    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  /var/log/nginx/access.log  main;

    sendfile            on;
    tcp_nopush          on;
    tcp_nodelay         on;
    keepalive_timeout   65;
    types_hash_max_size 2048;

    include             /etc/nginx/mime.types;
    default_type        application/octet-stream;
server {
        listen       80 default_server;
        server_name  _;

        location / {
        }
    }
}
EOF

启动Nginx 并且加入开机自启动

nginx -t
systemctl start nginx
systemctl enable nginx

我们代理apiservice的端口是16443， 验证端口是否启动

netstat -anput |grep 16443

2、安装keepalived及配置

在 master-1、 master-2主机同步执行，但是配置文件不一致！

yum -y install keepalived

添加脚本文件，实现当Nginx宕机后停止keepalived，VIP地址会漂移到另一个节点，从而实现apiservice的高可用。

vim /etc/keepalived/checkNginx.sh

#!/bin/bash
# egrep -cv "grep|$$" 过滤掉包含grep 或者 $$ 表示的当前Shell进程ID
count=$(ps -ef |grep nginx | grep sbin | egrep -cv "grep|$$")
if [ $count -eq 0 ];then
    systemctl stop keepalived
fi

赋予可执行权限

chmod +x /etc/keepalived/checkNginx.sh

Keepalived master-1主机配置文件内容：

mv /etc/keepalived/keepalived.conf{
    
    ,.default}

vim /etc/keepalived/keepalived.conf
vrrp_script checkNginx {
    
    
    script "/etc/keepalived/checkNginx.sh"      # 监控Nginx状态脚本
    interval 2
}

vrrp_instance VI_1 {
    
    
    state MASTER
    interface ens33        # 本机网卡名称
    virtual_router_id 51   # VRRP 路由 ID实例,每个实例是唯一的 
    priority 100           # 优先级
    advert_int 1           # 指定VRRP 心跳包通告间隔时间,默认1秒 
    authentication {
    
    
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
    
    
	16.32.15.100/24
    }

   track_script {
    
    
	checkNginx
    } 
}

Keepalived master-2备机配置文件内容：

mv /etc/keepalived/keepalived.conf{
    
    ,.default}
vim /etc/keepalived/keepalived.conf

vrrp_script checkNginx {
    
    
    script "/etc/keepalived/checkNginx.sh"      # 监控Nginx状态脚本
    interval 2
}

vrrp_instance VI_1 {
    
    
    state BACKUP           # 当前角色
    interface ens33        
    virtual_router_id 52   # VRRP 路由 ID实例,每个实例是唯一的 
    priority 90            # 优先级
    advert_int 1          
    authentication {
    
    
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
    
    
	16.32.15.100/24
    }

   track_script {
    
    
	checkNginx
    } 
}

重启keepalived(两台master同步执行)

systemctl restart keepalived

五、初始化Master集群

在master-1主机上进行操作

1、创建初始化文件

vim kubeadm-config.yaml

apiVersion: kubeadm.k8s.io/v1beta2
kind: ClusterConfiguration
kubernetesVersion: v1.23.0
controlPlaneEndpoint: 16.32.15.100:16443
imageRepository: registry.aliyuncs.com/google_containers
apiServer:
 certSANs:
 - 16.32.15.200
 - 16.32.15.201
 - 16.32.15.202
 - 16.32.15.100
networking:
  podSubnet: 10.244.0.0/16
  serviceSubnet: 10.10.0.0/16
---
apiVersion: kubeproxy.config.k8s.io/v1alpha1
kind:  KubeProxyConfiguration
mode: ipvs

• controlPlaneEndpoint：将集群的控制平面连接到一个负载均衡器(填写VIP地址)
• imageRepository：镜像下载地址，这里使用国内阿里云的
• certSANs：配置DNS，把集群涉及到的IP全部写上即可,包括VIP地址
• podSubnet：Pod网络段
• serviceSubnet：Service网络段

2、进行初始化

kubeadm init --config kubeadm-config.yaml --ignore-preflight-errors=SystemVerification

初始化成功后输出如下内容：

[init] Using Kubernetes version: v1.23.0
[preflight] Running pre-flight checks
[preflight] Pulling images required for setting up a Kubernetes cluster
[preflight] This might take a minute or two, depending on the speed of your internet connection
[preflight] You can also perform this action in beforehand using 'kubeadm config images pull'
[certs] Using certificateDir folder "/etc/kubernetes/pki"
[certs] Generating "ca" certificate and key
[certs] Generating "apiserver" certificate and key
[certs] apiserver serving cert is signed for DNS names [kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local master-1] and IPs [10.10.0.1 16.32.15.200 16.32.15.100 16.32.15.201 16.32.15.202]
[certs] Generating "apiserver-kubelet-client" certificate and key
[certs] Generating "front-proxy-ca" certificate and key
[certs] Generating "front-proxy-client" certificate and key
[certs] Generating "etcd/ca" certificate and key
[certs] Generating "etcd/server" certificate and key
[certs] etcd/server serving cert is signed for DNS names [localhost master-1] and IPs [16.32.15.200 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [localhost master-1] and IPs [16.32.15.200 127.0.0.1 ::1]
[certs] Generating "etcd/healthcheck-client" certificate and key
[certs] Generating "apiserver-etcd-client" certificate and key
[certs] Generating "sa" key and public key
[kubeconfig] Using kubeconfig folder "/etc/kubernetes"
[endpoint] WARNING: port specified in controlPlaneEndpoint overrides bindPort in the controlplane address
[kubeconfig] Writing "admin.conf" kubeconfig file
[endpoint] WARNING: port specified in controlPlaneEndpoint overrides bindPort in the controlplane address
[kubeconfig] Writing "kubelet.conf" kubeconfig file
[endpoint] WARNING: port specified in controlPlaneEndpoint overrides bindPort in the controlplane address
[kubeconfig] Writing "controller-manager.conf" kubeconfig file
[endpoint] WARNING: port specified in controlPlaneEndpoint overrides bindPort in the controlplane address
[kubeconfig] Writing "scheduler.conf" kubeconfig file
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Starting the kubelet
[control-plane] Using manifest folder "/etc/kubernetes/manifests"
[control-plane] Creating static Pod manifest for "kube-apiserver"
[control-plane] Creating static Pod manifest for "kube-controller-manager"
[control-plane] Creating static Pod manifest for "kube-scheduler"
[etcd] Creating static Pod manifest for local etcd in "/etc/kubernetes/manifests"
[wait-control-plane] Waiting for the kubelet to boot up the control plane as static Pods from directory "/etc/kubernetes/manifests". This can take up to 4m0s
[apiclient] All control plane components are healthy after 11.889660 seconds
[upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[kubelet] Creating a ConfigMap "kubelet-config-1.23" in namespace kube-system with the configuration for the kubelets in the cluster
NOTE: The "kubelet-config-1.23" naming of the kubelet ConfigMap is deprecated. Once the UnversionedKubeletConfigMap feature gate graduates to Beta the default name will become just "kubelet-config". Kubeadm upgrade will handle this transition transparently.
[upload-certs] Skipping phase. Please see --upload-certs
[mark-control-plane] Marking the node master-1 as control-plane by adding the labels: [node-role.kubernetes.io/master(deprecated) node-role.kubernetes.io/control-plane node.kubernetes.io/exclude-from-external-load-balancers]
[mark-control-plane] Marking the node master-1 as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]
[bootstrap-token] Using token: giw3n1.8ys41tcqlvl9xhrk
[bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles
[bootstrap-token] configured RBAC rules to allow Node Bootstrap tokens to get nodes
[bootstrap-token] configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials
[bootstrap-token] configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token
[bootstrap-token] configured RBAC rules to allow certificate rotation for all node client certificates in the cluster
[bootstrap-token] Creating the "cluster-info" ConfigMap in the "kube-public" namespace
[kubelet-finalize] Updating "/etc/kubernetes/kubelet.conf" to point to a rotatable kubelet client certificate and key
[addons] Applied essential addon: CoreDNS
[endpoint] WARNING: port specified in controlPlaneEndpoint overrides bindPort in the controlplane address
[addons] Applied essential addon: kube-proxy

Your Kubernetes control-plane has initialized successfully!

To start using your cluster, you need to run the following as a regular user:

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

Alternatively, if you are the root user, you can run:

  export KUBECONFIG=/etc/kubernetes/admin.conf

You should now deploy a pod network to the cluster.
Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
  https://kubernetes.io/docs/concepts/cluster-administration/addons/

You can now join any number of control-plane nodes by copying certificate authorities
and service account keys on each node and then running the following as root:

# 将master节点加入集群中
  kubeadm join 16.32.15.100:16443 --token giw3n1.8ys41tcqlvl9xhrk \
	--discovery-token-ca-cert-hash sha256:2e97fe276dd9a52e91704fbd985f8c57c73c6ca750f07e9eeaf695f7639e0287 \
	--control-plane 

Then you can join any number of worker nodes by running the following on each as root:

# 将node节点加入集群中
kubeadm join 16.32.15.100:16443 --token giw3n1.8ys41tcqlvl9xhrk \
	--discovery-token-ca-cert-hash sha256:2e97fe276dd9a52e91704fbd985f8c57c73c6ca750f07e9eeaf695f7639e0287 

配置kubectl的配置文件config，相当于对kubectl进行授权，这样kubectl命令可以使用这个证书对k8s集群进行管理

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

验证使用可以使用 kubectl 命令

kubectl get nodes

六、扩容K8S集群

1、扩容master节点

把master-1主节点的证书文件拷贝到master-2主机

master-2主机执行

cd /root && mkdir -p /etc/kubernetes/pki/etcd &&mkdir -p ~/.kube/

master-1主机执行 拷贝证书等文件到master-2主机

scp /etc/kubernetes/pki/ca.key master-2:/etc/kubernetes/pki/
scp /etc/kubernetes/pki/ca.crt master-2:/etc/kubernetes/pki/
scp /etc/kubernetes/pki/sa.key master-2:/etc/kubernetes/pki/
scp /etc/kubernetes/pki/sa.pub master-2:/etc/kubernetes/pki/
scp /etc/kubernetes/pki/front-proxy-ca.crt master-2:/etc/kubernetes/pki/
scp /etc/kubernetes/pki/front-proxy-ca.key master-2:/etc/kubernetes/pki/
scp /etc/kubernetes/pki/etcd/ca.crt master-2:/etc/kubernetes/pki/etcd/
scp /etc/kubernetes/pki/etcd/ca.key master-2:/etc/kubernetes/pki/etcd/

master-2主机执行 加入集群

kubeadm join 16.32.15.100:16443 --token giw3n1.8ys41tcqlvl9xhrk \
	--discovery-token-ca-cert-hash sha256:2e97fe276dd9a52e91704fbd985f8c57c73c6ca750f07e9eeaf695f7639e0287 \
	--control-plane

显示如下图表示成功加入集群中

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

master-1主机执行 查看node状态

kubectl get node

2、扩容node节点

node-1主机上执行 加入集群

kubeadm join 16.32.15.100:16443 --token giw3n1.8ys41tcqlvl9xhrk \
	--discovery-token-ca-cert-hash sha256:2e97fe276dd9a52e91704fbd985f8c57c73c6ca750f07e9eeaf695f7639e0287 

显示如下图表示成功加入集群中

master-1主机执行 查看node状态

kubectl get node

可以看到node-1的ROLES角色为空，就表示这个节点是工作节点。

可以把node-1的ROLES变成work，按照如下方法：

kubectl label node node-1 node-role.kubernetes.io/worker=worker

七、安装网络组件Calico

Calico在线文档地址：

Calico.yaml下载地址：

1、查看自带Pod状态

kubectl get pods -n kube-system

当我们查看自带Pod状态时，coredns是pending状态，这是因为还没有安装网络插件，等到下面安装好网络插件之后这个cordns就会变成running了

2、上传calico.yaml文件到服务器中，下面提供calico.yaml文件内容：

在master-1、master-2执行

kubectl apply -f  calico.yaml

3、查看集群状态 && 查看自带Pod状态

kubectl get nodes

kubectl get pods -n kube-system

八、部署Tomcat测试集群可用性

1、创建tomcat的pod资源

vim tomcat.yaml 

apiVersion: v1  #pod属于k8s核心组v1
kind: Pod  #创建的是一个Pod资源
metadata:  #元数据
  name: demo-pod  #pod名字
  namespace: default  #pod所属的名称空间
  labels:
    app: myapp  #pod具有的标签
    env: dev      #pod具有的标签
spec:
  containers:      #定义一个容器，容器是对象列表，下面可以有多个name
  - name:  tomcat-pod-java  #容器的名字
    ports:
    - containerPort: 8080
    image: tomcat:8.5-jre8-alpine   #容器使用的镜像
    imagePullPolicy: IfNotPresent

执行ymal文件

kubectl apply -f tomcat.yaml

查看pod状态

kubectl get pod

2、创建tomcat的service资源

vim tomcat-service.yaml 

apiVersion: v1
kind: Service
metadata:
  name: tomcat
spec:
  type: NodePort
  ports:
    - port: 8080
      nodePort: 30080
  selector:
    app: myapp
    env: dev

执行ymal文件

kubectl apply -f tomcat-service.yaml 

查看service状态

kubectl get svc

3、浏览器访问测试(任意节点+30080端口)

4、测试coredns

kubectl run busybox --image busybox:1.28 --restart=Never --rm -it busybox -- sh

If you don't see a command prompt, try pressing enter.


/ # nslookup kubernetes.default.svc.cluster.local
Server:    10.10.0.10
Address 1: 10.10.0.10 kube-dns.kube-system.svc.cluster.local

Name:      kubernetes.default.svc.cluster.local
Address 1: 10.10.0.1 kubernetes.default.svc.cluster.local

/ # nslookup tomcat.default.svc.cluster.local
Server:    10.10.0.10
Address 1: 10.10.0.10 kube-dns.kube-system.svc.cluster.local

Name:      tomcat.default.svc.cluster.local
Address 1: 10.10.164.81 tomcat.default.svc.cluster.local

• 注意：busybox要用指定的1.28版本，不能用最新版本，最新版本，nslookup会解析不到dns和ip