一、前置知识点

1.1 生产环境可部署Kubernetes集群的两种方式

目前生产部署Kubernetes集群主要有两种方式:

  • kubeadm

Kubeadm是一个K8s部署工具,提供kubeadm init和kubeadm join,用于快速部署Kubernetes集群。

  • 二进制包

从github下载发行版的二进制包,手动部署每个组件,组成Kubernetes集群。

这里采用kubeadm搭建集群。

kubeadm工具功能:

  • kubeadm init:初始化一个Master节点
  • kubeadm join:将工作节点加入集群
  • kubeadm upgrade:升级K8s版本
  • kubeadm token:管理 kubeadm join 使用的令牌
  • kubeadm reset:清空 kubeadm init 或者 kubeadm join 对主机所做的任何更改
  • kubeadm version:打印 kubeadm 版本
  • kubeadm alpha:预览可用的新功能

1.2 准备环境

服务器要求:

  • 建议最小硬件配置:2核CPU、2G内存、30G硬盘
  • 服务器最好可以访问外网,会有从网上拉取镜像需求,如果服务器不能上网,需要提前下载对应镜像并导入节点

软件环境:

软件

版本

操作系统

CentOS7.8_x64 (mini)

Docker

19-ce

Kubernetes

1.20

服务器整体规划:

角色

IP

其他单装组件

k8s-master1

192.168.31.61

docker,etcd,nginx,keepalived

k8s-master2

192.168.31.62

docker,etcd,nginx,keepalived

k8s-node1

192.168.31.63

docker,etcd

负载均衡器对外IP

192.168.31.88 (VIP)

 

架构图:

1.3 操作系统初始化配置

# 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
192.168.31.61 k8s-master1
192.168.31.62 k8s-master2
192.168.31.63 k8s-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

二、部署Nginx+Keepalived高可用负载均衡器

Kubernetes作为容器集群系统,通过健康检查+重启策略实现了Pod故障自我修复能力,通过调度算法实现将Pod分布式部署,并保持预期副本数,根据Node失效状态自动在其他Node拉起Pod,实现了应用层的高可用性。

针对Kubernetes集群,高可用性还应包含以下两个层面的考虑:Etcd数据库的高可用性和Kubernetes Master组件的高可用性。 而kubeadm搭建的K8s集群,Etcd只起了一个,存在单点,所以我们这里会独立搭建一个Etcd集群。

Master节点扮演着总控中心的角色,通过不断与工作节点上的Kubelet和kube-proxy进行通信来维护整个集群的健康工作状态。如果Master节点故障,将无法使用kubectl工具或者API做任何集群管理。

Master节点主要有三个服务kube-apiserver、kube-controller-manager和kube-scheduler,其中kube-controller-manager和kube-scheduler组件自身通过选择机制已经实现了高可用,所以Master高可用主要针对kube-apiserver组件,而该组件是以HTTP API提供服务,因此对他高可用与Web服务器类似,增加负载均衡器对其负载均衡即可,并且可水平扩容。

kube-apiserver高可用架构图:

  • Nginx是一个主流Web服务和反向代理服务器,这里用四层实现对apiserver实现负载均衡。
  • Keepalived是一个主流高可用软件,基于VIP绑定实现服务器双机热备,在上述拓扑中,Keepalived主要根据Nginx运行状态判断是否需要故障转移(偏移VIP),例如当Nginx主节点挂掉,VIP会自动绑定在Nginx备节点,从而保证VIP一直可用,实现Nginx高可用。

注:为了节省机器,这里与K8s master节点机器复用。也可以独立于k8s集群之外部署,只要nginx与apiserver能通信就行。

2.1 安装软件包(主/备)

 yum install epel-release -y

 yum install nginx keepalived -y

2.2 Nginx配置文件(主/备一样)

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;
}

# 四层负载均衡,为两台Master apiserver组件提供负载均衡
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 192.168.31.61:6443;   # Master1 APISERVER IP:PORT
       server 192.168.31.62:6443;   # Master2 APISERVER IP:PORT
    }
    
    server {
       listen 16443;  # 由于nginx与master节点复用,这个监听端口不能是6443,否则会冲突
       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

2.3 keepalived配置文件(Nginx Master)

cat > /etc/keepalived/keepalived.conf << EOF
global_defs {
   notification_email {
     acassen@firewall.loc
     failover@firewall.loc
     sysadmin@firewall.loc
   }
   notification_email_from Alexandre.Cassen@firewall.loc  
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id NGINX_MASTER
}

vrrp_script check_nginx {
    script "/etc/keepalived/check_nginx.sh"
}

vrrp_instance VI_1 {
    state MASTER
    interface ens33  # 修改为实际网卡名
    virtual_router_id 51 # VRRP 路由 ID实例,每个实例是唯一的
    priority 100    # 优先级,备服务器设置 90
    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
    }  
    # 虚拟IP
    virtual_ipaddress {
        192.168.31.88/24
    }
    track_script {
        check_nginx
    }
}
EOF

vrrp_script:指定检查nginx工作状态脚本(根据nginx状态判断是否故障转移)
virtual_ipaddress:虚拟IP(VIP)
准备上述配置文件中检查nginx运行状态的脚本:

cat > /etc/keepalived/check_nginx.sh  << "EOF"
#!/bin/bash
count=$(ss -antp |grep 16443 |egrep -cv "grep|$$")

if [ "$count" -eq 0 ];then
    exit 1
else
    exit 0
fi
EOF
chmod +x /etc/keepalived/check_nginx.sh

2.4 keepalived配置文件(Nginx Backup)

cat > /etc/keepalived/keepalived.conf << EOF
global_defs {
   notification_email {
     acassen@firewall.loc
     failover@firewall.loc
     sysadmin@firewall.loc
   }
   notification_email_from Alexandre.Cassen@firewall.loc  
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id NGINX_BACKUP
}

vrrp_script check_nginx {
    script "/etc/keepalived/check_nginx.sh"
}

vrrp_instance VI_1 {
    state BACKUP
    interface ens33
    virtual_router_id 51 # VRRP 路由 ID实例,每个实例是唯一的
    priority 90
    advert_int 1
    authentication {
        auth_type PASS      
        auth_pass 1111
    }  
    virtual_ipaddress {
        192.168.31.88/24
    }
    track_script {
        check_nginx
    }
}
EOF

准备上述配置文件中检查nginx运行状态的脚本:

cat > /etc/keepalived/check_nginx.sh  << "EOF"
#!/bin/bash
count=$(ss -antp |grep 16443 |egrep -cv "grep|$$")

if [ "$count" -eq 0 ];then
    exit 1
else
    exit 0
fi
EOF
chmod +x /etc/keepalived/check_nginx.sh

注:keepalived根据脚本返回状态码(0为工作正常,非0不正常)判断是否故障转移。

2.5 启动并设置开机启动

systemctl daemon-reload
systemctl start nginx
systemctl start keepalived
systemctl enable nginx
systemctl enable keepalived

2.6 查看keepalived工作状态

ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:04:f7:2c brd ff:ff:ff:ff:ff:ff
    inet 192.168.31.80/24 brd 192.168.31.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet 192.168.31.88/24 scope global secondary ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe04:f72c/64 scope link
       valid_lft forever preferred_lft forever

可以看到,在ens33网卡绑定了192.168.31.88 虚拟IP,说明工作正常。

2.7 Nginx+Keepalived高可用测试

关闭主节点Nginx,测试VIP是否漂移到备节点服务器。

在Nginx Master执行 pkill nginx
在Nginx Backup,ip addr命令查看已成功绑定VIP。

三、部署Etcd集群

如果你在学习中遇到问题或者文档有误可联系阿良~ 微信: xyz12366699

Etcd 是一个分布式键值存储系统,Kubernetes使用Etcd进行数据存储,kubeadm搭建默认情况下只启动一个Etcd Pod,存在单点故障,生产环境强烈不建议,所以我们这里使用3台服务器组建集群,可容忍1台机器故障,当然,你也可以使用5台组建集群,可容忍2台机器故障。

节点名称

IP

etcd-1

192.168.31.61

etcd-2

192.168.31.62

etcd-3

192.168.31.63

注:为了节省机器,这里与K8s节点机器复用。也可以独立于k8s集群之外部署,只要apiserver能连接到就行。

3.1 准备cfssl证书生成工具

cfssl是一个开源的证书管理工具,使用json文件生成证书,相比openssl更方便使用。

找任意一台服务器操作,这里用Master节点。

wget https://pkg.cfssl.org/R1.2/cfssl_linux-amd64
wget https://pkg.cfssl.org/R1.2/cfssljson_linux-amd64
wget https://pkg.cfssl.org/R1.2/cfssl-certinfo_linux-amd64
chmod +x cfssl_linux-amd64 cfssljson_linux-amd64 cfssl-certinfo_linux-amd64
mv cfssl_linux-amd64 /usr/local/bin/cfssl
mv cfssljson_linux-amd64 /usr/local/bin/cfssljson
mv cfssl-certinfo_linux-amd64 /usr/bin/cfssl-certinfo

3.2 生成Etcd证书

1. 自签证书颁发机构(CA)

创建工作目录:

mkdir -p ~/etcd_tls
cd ~/etcd_tls

自签CA:

cat > ca-config.json << EOF
{
  "signing": {
    "default": {
      "expiry": "87600h"
    },
    "profiles": {
      "www": {
         "expiry": "87600h",
         "usages": [
            "signing",
            "key encipherment",
            "server auth",
            "client auth"
        ]
      }
    }
  }
}
EOF

cat > ca-csr.json << EOF
{
    "CN": "etcd CA",
    "key": {
        "algo": "rsa",
        "size": 2048
    },
    "names": [
        {
            "C": "CN",
            "L": "Beijing",
            "ST": "Beijing"
        }
    ]
}
EOF

生成证书:

cfssl gencert -initca ca-csr.json | cfssljson -bare ca -

会生成ca.pem和ca-key.pem文件。

2. 使用自签CA签发Etcd HTTPS证书

创建证书申请文件:

cat > server-csr.json << EOF
{
    "CN": "etcd",
    "hosts": [
    "192.168.31.61",
    "192.168.31.62",
    "192.168.31.63"
    ],
    "key": {
        "algo": "rsa",
        "size": 2048
    },
    "names": [
        {
            "C": "CN",
            "L": "BeiJing",
            "ST": "BeiJing"
        }
    ]
}
EOF

注:上述文件hosts字段中IP为所有etcd节点的集群内部通信IP,一个都不能少!为了方便后期扩容可以多写几个预留的IP。

生成证书:

cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=www server-csr.json | cfssljson -bare server

会生成server.pem和server-key.pem文件。

3.3 从Github下载二进制文件

下载地址:https://github.com/etcd-io/etcd/releases/download/v3.4.9/etcd-v3.4.9-linux-amd64.tar.gz

3.4 部署Etcd集群

以下在节点1上操作,为简化操作,待会将节点1生成的所有文件拷贝到节点2和节点3。

1. 创建工作目录并解压二进制包

mkdir /opt/etcd/{bin,cfg,ssl} -p
tar zxvf etcd-v3.4.9-linux-amd64.tar.gz
mv etcd-v3.4.9-linux-amd64/{etcd,etcdctl} /opt/etcd/bin/

2. 创建etcd配置文件

cat > /opt/etcd/cfg/etcd.conf << EOF
#[Member]
ETCD_NAME="etcd-1"
ETCD_DATA_DIR="/var/lib/etcd/default.etcd"
ETCD_LISTEN_PEER_URLS="https://192.168.31.61:2380"
ETCD_LISTEN_CLIENT_URLS="https://192.168.31.61:2379"

#[Clustering]
ETCD_INITIAL_ADVERTISE_PEER_URLS="https://192.168.31.61:2380"
ETCD_ADVERTISE_CLIENT_URLS="https://192.168.31.61:2379"
ETCD_INITIAL_CLUSTER="etcd-1=https://192.168.31.61:2380,etcd-2=https://192.168.31.62:2380,etcd-3=https://192.168.31.63:2380"
ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
ETCD_INITIAL_CLUSTER_STATE="new"
EOF

ETCD_NAME:节点名称,集群中唯一
ETCDDATADIR:数据目录
ETCDLISTENPEER_URLS:集群通信监听地址
ETCDLISTENCLIENT_URLS:客户端访问监听地址
ETCDINITIALADVERTISEPEERURLS:集群通告地址
ETCDADVERTISECLIENT_URLS:客户端通告地址
ETCDINITIALCLUSTER:集群节点地址
ETCDINITIALCLUSTER_TOKEN:集群Token
ETCDINITIALCLUSTER_STATE:加入集群的当前状态,new是新集群,existing表示加入已有集群
3. systemd管理etcd

cat > /usr/lib/systemd/system/etcd.service << EOF
[Unit]
Description=Etcd Server
After=network.target
After=network-online.target
Wants=network-online.target

[Service]
Type=notify
EnvironmentFile=/opt/etcd/cfg/etcd.conf
ExecStart=/opt/etcd/bin/etcd \
--cert-file=/opt/etcd/ssl/server.pem \
--key-file=/opt/etcd/ssl/server-key.pem \
--peer-cert-file=/opt/etcd/ssl/server.pem \
--peer-key-file=/opt/etcd/ssl/server-key.pem \
--trusted-ca-file=/opt/etcd/ssl/ca.pem \
--peer-trusted-ca-file=/opt/etcd/ssl/ca.pem \
--logger=zap
Restart=on-failure
LimitNOFILE=65536

[Install]
WantedBy=multi-user.target
EOF

4. 拷贝刚才生成的证书

把刚才生成的证书拷贝到配置文件中的路径:

cp ~/etcd_tls/ca*pem ~/etcd_tls/server*pem /opt/etcd/ssl/

5. 启动并设置开机启动

systemctl daemon-reload
systemctl start etcd
systemctl enable etcd

6. 将上面节点1所有生成的文件拷贝到节点2和节点3

scp -r /opt/etcd/ root@192.168.31.62:/opt/
scp /usr/lib/systemd/system/etcd.service root@192.168.31.62:/usr/lib/systemd/system/
scp -r /opt/etcd/ root@192.168.31.63:/opt/
scp /usr/lib/systemd/system/etcd.service root@192.168.31.63:/usr/lib/systemd/system/

然后在节点2和节点3分别修改etcd.conf配置文件中的节点名称和当前服务器IP:

vi /opt/etcd/cfg/etcd.conf
#[Member]
ETCD_NAME="etcd-1"   # 修改此处,节点2改为etcd-2,节点3改为etcd-3
ETCD_DATA_DIR="/var/lib/etcd/default.etcd"
ETCD_LISTEN_PEER_URLS="https://192.168.31.71:2380"   # 修改此处为当前服务器IP
ETCD_LISTEN_CLIENT_URLS="https://192.168.31.71:2379" # 修改此处为当前服务器IP

#[Clustering]
ETCD_INITIAL_ADVERTISE_PEER_URLS="https://192.168.31.71:2380" # 修改此处为当前服务器IP
ETCD_ADVERTISE_CLIENT_URLS="https://192.168.31.71:2379" # 修改此处为当前服务器IP
ETCD_INITIAL_CLUSTER="etcd-1=https://192.168.31.71:2380,etcd-2=https://192.168.31.72:2380,etcd-3=https://192.168.31.73:2380"
ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
ETCD_INITIAL_CLUSTER_STATE="new"

最后启动etcd并设置开机启动,同上。

7. 查看集群状态

ETCDCTL_API=3 /opt/etcd/bin/etcdctl --cacert=/opt/etcd/ssl/ca.pem --cert=/opt/etcd/ssl/server.pem --key=/opt/etcd/ssl/server-key.pem --endpoints="https://192.168.31.61:2379,https://192.168.31.62:2379,https://192.168.31.63:2379" endpoint health --write-out=table

+----------------------------+--------+-------------+-------+
|          ENDPOINT    | HEALTH |    TOOK     | ERROR |
+----------------------------+--------+-------------+-------+
| https://192.168.31.61:2379 |   true | 10.301506ms |    |
| https://192.168.31.63:2379 |   true | 12.87467ms |     |
| https://192.168.31.62:2379 |   true | 13.225954ms |    |
+----------------------------+--------+-------------+-------+

如果输出上面信息,就说明集群部署成功。

如果有问题第一步先看日志:/var/log/message 或 journalctl -u etcd

四、安装Docker/kubeadm/kubelet【所有节点】

这里使用Docker作为容器引擎,也可以换成别的,例如containerd

4.1 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
systemctl enable docker && systemctl start docker

配置镜像下载加速器:

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

systemctl restart docker
docker info

4.2 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

4.3 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-1.20.0 kubeadm-1.20.0 kubectl-1.20.0
systemctl enable kubelet

五、部署Kubernetes Master

5.1 初始化Master1

生成初始化配置文件:

cat > kubeadm-config.yaml << EOF
apiVersion: kubeadm.k8s.io/v1beta2
bootstrapTokens:
- groups:
  - system:bootstrappers:kubeadm:default-node-token
  token: 9037x2.tcaqnpaqkra9vsbw
  ttl: 24h0m0s
  usages:
  - signing
  - authentication
kind: InitConfiguration
localAPIEndpoint:
  advertiseAddress: 192.168.31.61
  bindPort: 6443
nodeRegistration:
  criSocket: /var/run/dockershim.sock
  name: k8s-master1
  taints:
  - effect: NoSchedule
    key: node-role.kubernetes.io/master
---
apiServer:
  certSANs:  # 包含所有Master/LB/VIP IP,一个都不能少!为了方便后期扩容可以多写几个预留的IP。
  - k8s-master1
  - k8s-master2
  - 192.168.31.61
  - 192.168.31.62
  - 192.168.31.63
  - 127.0.0.1
  extraArgs:
    authorization-mode: Node,RBAC
  timeoutForControlPlane: 4m0s
apiVersion: kubeadm.k8s.io/v1beta2
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controlPlaneEndpoint: 192.168.31.88:16443 # 负载均衡虚拟IP(VIP)和端口
controllerManager: {}
dns:
  type: CoreDNS
etcd:
  external:  # 使用外部etcd
    endpoints:
    - https://192.168.31.61:2379 # etcd集群3个节点
    - https://192.168.31.62:2379
    - https://192.168.31.63:2379
    caFile: /opt/etcd/ssl/ca.pem # 连接etcd所需证书
    certFile: /opt/etcd/ssl/server.pem
    keyFile: /opt/etcd/ssl/server-key.pem
imageRepository: registry.aliyuncs.com/google_containers # 由于默认拉取镜像地址k8s.gcr.io国内无法访问,这里指定阿里云镜像仓库地址
kind: ClusterConfiguration
kubernetesVersion: v1.20.0 # K8s版本,与上面安装的一致
networking:
  dnsDomain: cluster.local
  podSubnet: 10.244.0.0/16  # Pod网络,与下面部署的CNI网络组件yaml中保持一致
  serviceSubnet: 10.96.0.0/12  # 集群内部虚拟网络,Pod统一访问入口
scheduler: {}
EOF

或者使用配置文件引导:

kubeadm init --config kubeadm-config.yaml
...
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:

  kubeadm join 192.168.31.88:16443 --token 9037x2.tcaqnpaqkra9vsbw \
    --discovery-token-ca-cert-hash sha256:b1e726042cdd5df3ce62e60a2f86168cd2e64bff856e061e465df10cd36295b8 \
    --control-plane

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

kubeadm join 192.168.31.88:16443 --token 9037x2.tcaqnpaqkra9vsbw \
    --discovery-token-ca-cert-hash sha256:b1e726042cdd5df3ce62e60a2f86168cd2e64bff856e061e465df10cd36295b8

初始化完成后,会有两个join的命令,带有 --control-plane 是用于加入组建多master集群的,不带的是加入节点的。

拷贝kubectl使用的连接k8s认证文件到默认路径:

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 node
NAME          STATUS     ROLES                  AGE     VERSION
k8s-master1   NotReady   control-plane,master   6m42s   v1.20.0

5.2 初始化Master2

将Master1节点生成的证书拷贝到Master2:

 scp -r /etc/kubernetes/pki/ 192.168.31.62:/etc/kubernetes/

复制加入master join命令在master2执行:

  kubeadm join 192.168.31.88:16443 --token 9037x2.tcaqnpaqkra9vsbw \
    --discovery-token-ca-cert-hash sha256:b1e726042cdd5df3ce62e60a2f86168cd2e64bff856e061e465df10cd36295b8 \
    --control-plane

拷贝kubectl使用的连接k8s认证文件到默认路径:

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 node
NAME          STATUS     ROLES                  AGE     VERSION
k8s-master1   NotReady   control-plane,master   28m     v1.20.0
k8s-master2   NotReady   control-plane,master   2m12s   v1.20.0

注:由于网络插件还没有部署,还没有准备就绪 NotReady

5.3 访问负载均衡器测试

找K8s集群中任意一个节点,使用curl查看K8s版本测试,使用VIP访问:

curl -k https://192.168.31.88:16443/version
{
  "major": "1",
  "minor": "20",
  "gitVersion": "v1.20.0",
  "gitCommit": "e87da0bd6e03ec3fea7933c4b5263d151aafd07c",
  "gitTreeState": "clean",
  "buildDate": "2021-02-18T16:03:00Z",
  "goVersion": "go1.15.8",
  "compiler": "gc",
  "platform": "linux/amd64"

}

可以正确获取到K8s版本信息,说明负载均衡器搭建正常。该请求数据流程:curl -> vip(nginx) -> apiserver

通过查看Nginx日志也可以看到转发apiserver IP:

tail /var/log/nginx/k8s-access.log -f
192.168.31.71 192.168.31.71:6443 - [02/Apr/2021:19:17:57 +0800] 200 423
192.168.31.71 192.168.31.72:6443 - [02/Apr/2021:19:18:50 +0800] 200 423

六、加入Kubernetes Node

在192.168.31.63(Node)执行。

向集群添加新节点,执行在kubeadm init输出的kubeadm join命令:

kubeadm join 192.168.31.88:16443 --token 9037x2.tcaqnpaqkra9vsbw \
    --discovery-token-ca-cert-hash sha256:e6a724bb7ef8bb363762fbaa088f6eb5975e0c654db038560199a7063735a697

后续其他节点也是这样加入。

注:默认token有效期为24小时,当过期之后,该token就不可用了。这时就需要重新创建token,可以直接使用命令快捷生成:kubeadm token create --print-join-command

七、部署网络组件

Calico是一个纯三层的数据中心网络方案,是目前Kubernetes主流的网络方案。

部署Calico:

kubectl apply -f https://docs.projectcalico.org/manifests/calico.yaml
kubectl get pods -n kube-system

等Calico Pod都Running,节点也会准备就绪:

kubectl get node
NAME          STATUS   ROLES                  AGE   VERSION
k8s-master1    Ready    control-plane,master   50m   v1.20.0
k8s-master2    Ready    control-plane,master   24m   v1.20.0
k8s-node1     Ready    <none>            20m   v1.20.0

八、部署 Dashboard

Dashboard是官方提供的一个UI,可用于基本管理K8s资源。

kubectl apply -f kubernetes-dashboard.yaml
# 查看部署
kubectl get pods -n kubernetes-dashboard

访问地址:https://NodeIP:30001

创建service account并绑定默认cluster-admin管理员集群角色:

kubectl create serviceaccount dashboard-admin -n kube-system
kubectl create clusterrolebinding dashboard-admin --clusterrole=cluster-admin --serviceaccount=kube-system:dashboard-admin
kubectl describe secrets -n kube-system $(kubectl -n kube-system get secret | awk '/dashboard-admin/{print $1}')

使用输出的token登录Dashboard。

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