kubernetes-v1.20.4 二进制部署(二) kube-apiserver

一、安装部署kube-apiserver

　　1、生成kube-apiserver证书，自签证书颁发机构（CA）

cd ~/TLS/k8s
cat > ca-config.json << EOF
{
  "signing": {
    "default": {
      "expiry": "175200h"
    },
    "profiles": {
      "kubernetes": {
         "expiry": "175200h",
         "usages": [
            "signing",
            "key encipherment",
            "server auth",
            "client auth"
        ]
      }
    }
  }
}
EOF
cat > ca-csr.json << EOF
{
    "CN": "kubernetes",
    "key": {
        "algo": "rsa",
        "size": 2048
    },
    "names": [
        {
            "C": "CN",
            "L": "Beijing",
            "ST": "Beijing",
            "O": "k8s",
            "OU": "System"
        }
    ]
}
EOF

cfssl gencert -initca ca-csr.json | cfssljson -bare ca -                      生成证书
ls *pem
ca-key.pem  ca.pem

　　2、创建证书申请文件，使用自签CA签发kube-apiserver HTTPS证书

cd ~/TLS/k8s
cat > server-csr.json << EOF
{
    "CN": "kubernetes",
    "hosts": [
      "10.0.0.1",
      "127.0.0.1",
      "192.168.112.110",
      "192.168.112.111",
      "192.168.112.112",
      "192.168.112.113",
      "192.168.112.114",
      "192.168.112.115",
      "192.168.112.120",
      "kubernetes",
      "kubernetes.default",
      "kubernetes.default.svc",
      "kubernetes.default.svc.cluster",
      "kubernetes.default.svc.cluster.local"
    ],
    "key": {
        "algo": "rsa",
        "size": 2048
    },
    "names": [
        {
            "C": "CN",
            "L": "BeiJing",
            "ST": "BeiJing",
            "O": "k8s",
            "OU": "System"
        }
    ]
}
EOF

cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=kubernetes server-csr.json | cfssljson -bare server       生成证书
ls server*pem
server-key.pem  server.pem

　　上述文件hosts字段中IP为所有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。

　　3、下载二进制包

下载地址： https://storage.googleapis.com/kubernetes-release/release/v1.20.4/kubernetes-server-linux-amd64.tar.gz

　　4、解压二进制包

mkdir -p /opt/kubernetes/{bin,cfg,ssl,logs} 
tar zxvf kubernetes-server-linux-amd64.tar.gz
cd kubernetes/server/bin
cp kube-apiserver kube-scheduler kube-controller-manager /opt/kubernetes/bin
cp kubectl /usr/bin/

　　5、创建kube-apiserver配置文件

cat > /opt/kubernetes/cfg/kube-apiserver.conf << EOF
KUBE_APISERVER_OPTS="--logtostderr=false \\
--v=2 \\
--log-dir=/opt/kubernetes/logs \\
--etcd-servers=https://192.168.112.110:2379,https://192.168.112.111:2379,https://192.168.112.112:2379 \\
--bind-address=192.168.112.110 \\
--secure-port=6443 \\
--advertise-address=192.168.112.110 \\
--allow-privileged=true \\
--service-cluster-ip-range=10.0.0.0/24 \\
--enable-admission-plugins=NamespaceLifecycle,LimitRanger,ServiceAccount,ResourceQuota,NodeRestriction \\
--authorization-mode=RBAC,Node \\
--enable-bootstrap-token-auth=true \\
--token-auth-file=/opt/kubernetes/cfg/token.csv \\
--service-node-port-range=30000-32767 \\
--kubelet-client-certificate=/opt/kubernetes/ssl/server.pem \\
--kubelet-client-key=/opt/kubernetes/ssl/server-key.pem \\
--tls-cert-file=/opt/kubernetes/ssl/server.pem  \\
--tls-private-key-file=/opt/kubernetes/ssl/server-key.pem \\
--client-ca-file=/opt/kubernetes/ssl/ca.pem \\
--service-account-key-file=/opt/kubernetes/ssl/ca-key.pem \\
--etcd-cafile=/opt/kubernetes/ssl/etcd/ca.pem \\
--etcd-certfile=/opt/kubernetes/ssl/etcd/server.pem \\
--etcd-keyfile=/opt/kubernetes/ssl/etcd/server-key.pem \\
--service-account-issuer=api \\
--service-account-signing-key-file=/opt/kubernetes/ssl/server-key.pem \\
--requestheader-client-ca-file=/opt/kubernetes/ssl/ca.pem \\
--proxy-client-cert-file=/opt/kubernetes/ssl/server.pem \\
--proxy-client-key-file=/opt/kubernetes/ssl/server-key.pem \\
--requestheader-allowed-names=kubernetes \\
--requestheader-extra-headers-prefix=X-Remote-Extra- \\
--requestheader-group-headers=X-Remote-Group \\
--requestheader-username-headers=X-Remote-User \\
--enable-aggregator-routing=true \\
--audit-log-maxage=30 \\
--audit-log-maxbackup=3 \\
--audit-log-maxsize=100 \\
--audit-log-path=/opt/kubernetes/logs/k8s-audit.log"
EOF

注：上面两个\ \ 第一个是转义符，第二个是换行符，使用转义符是为了使用EOF保留换行符。

–logtostderr：启用日志
—v：日志等级
–log-dir：日志目录
–etcd-servers：etcd集群地址
–bind-address：监听地址
–secure-port：https安全端口
–advertise-address：集群通告地址
–allow-privileged：启用授权
–service-cluster-ip-range：Service虚拟IP地址段
–enable-admission-plugins：准入控制模块
–authorization-mode：认证授权，启用RBAC授权和节点自管理
–enable-bootstrap-token-auth：启用TLS bootstrap机制
–token-auth-file：bootstrap token文件
–service-node-port-range：Service nodeport类型默认分配端口范围
–kubelet-client-xxx：apiserver访问kubelet客户端证书
–tls-xxx-file：apiserver https证书
–etcd-xxxfile：连接Etcd集群证书
–audit-log-xxx：审计日志

　　6、拷贝刚才生成的证书

cp ~/TLS/k8s/ca*pem ~/TLS/k8s/server*pem /opt/kubernetes/ssl/

　　7、systemd管理apiserver

cat > /usr/lib/systemd/system/kube-apiserver.service << EOF
[Unit]
Description=Kubernetes API Server
Documentation=https://github.com/kubernetes/kubernetes
[Service]
EnvironmentFile=/opt/kubernetes/cfg/kube-apiserver.conf
ExecStart=/opt/kubernetes/bin/kube-apiserver \$KUBE_APISERVER_OPTS
Restart=on-failure
[Install]
WantedBy=multi-user.target
EOF

　　8、启用 TLS Bootstrapping 机制

　　TLS Bootstraping：Master apiserver启用TLS认证后，Node节点kubelet和kube-proxy要与kube-apiserver进行通信，必须使用CA签发的有效证书才可以，当Node节点很多时，这种客户端证书颁发需要大量工作，同样也会增加集群扩展复杂度。为了简化流程，Kubernetes引入了TLS bootstraping机制来自动颁发客户端证书，kubelet会以一个低权限用户自动向apiserver申请证书，kubelet的证书由apiserver动态签署。所以强烈建议在Node上使用这种方式，目前主要用于kubelet，kube-proxy还是由我们统一颁发一个证书。
TLS bootstraping 工作流程：

　　　　1）创建上述配置文件中token文件：

cat > /opt/kubernetes/cfg/token.csv << EOF
c47ffb939f5ca36231d9e3121a252940,kubelet-bootstrap,10001,"system:node-bootstrapper"
EOF

　　　　格式：token，用户名，UID，用户组，

　　　　token也可自行生成替换：

head -c 16 /dev/urandom | od -An -t x | tr -d ' '

　　　　2）签发admin证书

cd ~/TLS/k8s
cat > admin-csr.json << EOF
{
  "CN": "admin",
  "hosts": [],
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "CN",
      "L": "BeiJing",
      "ST": "BeiJing",
      "O": "system:masters",
      "OU": "System"
    }
  ]
}
EOF

cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=kubernetes admin-csr.json | cfssljson -bare admin
cp admin.pem admin-key.pem /opt/kubernetes/ssl

　　　　3）创建config文件

mkdir /root/.kube/  && cd  /root/.kube/

cat > config << EOF
apiVersion: v1
clusters:
- cluster:
    certificate-authority: /opt/kubernetes/ssl/ca.pem
    server: https://192.168.112.120:7443
  name: kubernetes
contexts:
- context:
    cluster: kubernetes
    user: admin
  name: default
current-context: default
kind: Config
preferences: {}
users:
- name: admin
  user:
    client-certificate: /opt/kubernetes/ssl/admin.pem
    client-key: /opt/kubernetes/ssl/admin-key.pem
EOF

　　9、拷贝安装文件至另一台master节点上

scp -r /opt/kubernetes/ root@192.168.112.111:/opt
scp -r /root/.kube/config root@192.168.112.111:/root/.kube
scp /usr/lib/systemd/system/kube-apiserver.service root@192.168.112.111:/usr/lib/systemd/system/                    

　　注意：从节点记得修改kube-apiserver.conf中的主机IP地址

　　10、启动并设置开机启动

systemctl daemon-reload
systemctl start kube-apiserver
systemctl enable kube-apiserver

二、安装nginx和keepalived，对apiserver做高可用负载

　　1、在两台master节点安装nginx

　　　　1）编辑yum文件

vim /etc/yum.repos.d/nginx.repo

[nginx-stable]
name=nginx stable repo
baseurl=http://nginx.org/packages/centos/$releasever/$basearch/
gpgcheck=1
enabled=1
gpgkey=https://nginx.org/keys/nginx_signing.key
module_hotfixes=true

[nginx-mainline]
name=nginx mainline repo
baseurl=http://nginx.org/packages/mainline/centos/$releasever/$basearch/
gpgcheck=1
enabled=0
gpgkey=https://nginx.org/keys/nginx_signing.key
module_hotfixes=true

　　　　2）安装最新版nginx

yum install nginx -y

　　2、编辑nginx配置文件，nginx四层负载，必须与http同级

vi /etc/nginx/nginx.conf

stream {
    upstream kube-apiserver {
        server 192.168.112.110:6443     max_fails=3 fail_timeout=30s;
        server 192.168.112.111:6443     max_fails=3 fail_timeout=30s;
    }
    server {
        listen 7443;
        proxy_connect_timeout 2s;
        proxy_timeout 900s;
        proxy_pass kube-apiserver;
    }
}

　　3、启动nginx

nginx -t
systemctl start nginx
systemctl enable nginx

　　4、部署keepalived实现高可用

yum install keepalived -y

　　5、编写keepalived监控脚本

vi /etc/keepalived/check_port.sh

#!/bin/bash
#keepalived 监控端口脚本
#使用方法：
#在keepalived的配置文件中
#vrrp_script check_port {#创建一个vrrp_script脚本,检查配置
#    script "/etc/keepalived/check_port.sh 6379" #配置监听的端口
#    interval 2 #检查脚本的频率,单位（秒）
#}
CHK_PORT=$1
if [ -n "$CHK_PORT" ];then
        PORT_PROCESS=`ss -lnt|grep $CHK_PORT|wc -l`
        if [ $PORT_PROCESS -eq 0 ];then
                echo "Port $CHK_PORT Is Not Used,End."
                exit 1
        fi
else
        echo "Check Port Cant Be Empty!"
fi

　　6、对监控脚本授权

chmod +x /etc/keepalived/check_port.sh

　　7、编辑keepalived配置文件，注意主从配置文件不一样

vi /etc/keepalived/keepalived.conf
主：
! Configuration File for keepalived
 
global_defs {
   router_id 192.168.112.110
 
}
 
vrrp_script chk_nginx {
    script "/etc/keepalived/check_port.sh 7443"
    interval 2
    weight -20
}
 
vrrp_instance VI_1 {
    state MASTER
    interface ens192                       修改网卡名字
    virtual_router_id 251
    priority 100
    advert_int 1
    mcast_src_ip 192.168.112.110
    nopreempt   #非抢占式 ，当主节点挂了以后，从节点vip飘到从上，主节点恢复以后，不主动飘回主，需要手动重启keepalived
 
    authentication {
        auth_type PASS
        auth_pass 11111111
    }
    track_script {
         chk_nginx
    }
    virtual_ipaddress {
        192.168.112.120
    }
}

从：
! Configuration File for keepalived
global_defs {
    router_id  192.168.112.111
}
vrrp_script chk_nginx {
    script "/etc/keepalived/check_port.sh 7443"
    interval 2
    weight -20
}
vrrp_instance VI_1 {
    state BACKUP
    interface ens192                     修改网卡名字
    virtual_router_id 251
    mcast_src_ip  192.168.112.111
    priority 90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 11111111
    }
    track_script {
        chk_nginx
    }
    virtual_ipaddress {
        192.168.112.120
    }
}

　　8、启动keepalived并配置开机自启

systemctl start keepalived
systemctl enable keepalived

　　9、检查VIP情况

　　 如果keepalived出现脑裂问题，两台上面都有vip，可以加入以下配置，将多播修改成单播

　 至此，apiserver部署完成，并且配置了负载高可用。

　 10、授权kubelet-bootstrap用户允许请求证书

kubectl create clusterrolebinding kubelet-bootstrap \
--clusterrole=system:node-bootstrapper \
--user=kubelet-bootstrap