k8s部署---master节点组件部署（三）

kube-APIserver组件介绍

• kube-APIserver提供了k8s各类资源对象（pod,RC,Service等）的增删改查及watch等HTTP Rest接口，是整个系统的数据总线和数据中心。

kube-APIserver的功能

• 提供了集群管理的REST API接口(包括认证授权、数据校验以及集群状态变更)
• 提供其他模块之间的数据交互和通信的枢纽（其他模块通过API Server查询或修改数据，只有API Server才直接操作etcd）
• 是资源配额控制的入口
• 拥有完备的集群安全机制

kube-apiserver工作原理图

kubernetes API的访问

• k8s通过kube-apiserver这个进程提供服务，该进程运行在单个k8s-master节点上。默认有两个端口
  • 本地端口
  • 该端口用于接收HTTP请求
  • 该端口默认值为8080，可以通过API Server的启动参数“--insecure-port”的值来修改默认值
  • 默认的IP地址为“localhost”，可以通过启动参数“--insecure-bind-address”的值来修改该IP地址
  • 非认证或授权的HTTP请求通过该端口访问API Server
  • 安全端口
  • 该端口默认值为6443，可通过启动参数“--secure-port”的值来修改默认值
  • 默认IP地址为非本地（Non-Localhost）网络端口，通过启动参数“--bind-address”设置该值
  • 该端口用于接收HTTPS请求
  • 用于基于Tocken文件或客户端证书及HTTP Base的认证
  • 用于基于策略的授权
  • 默认不启动HTTPS安全访问控制

kube-controller-manager组件介绍

• kube-Controller Manager作为集群内部的管理控制中心，负责集群内的Node、Pod副本、服务端点（Endpoint）、命名空间（Namespace）、服务账号（ServiceAccount）、资源定额（ResourceQuota）的管理，当某个Node意外宕机时，Controller Manager会及时发现并执行自动化修复流程，确保集群始终处于预期的工作状态。

kube-scheduler组件介绍

• kube-scheduler是以插件形式存在的组件，正因为以插件形式存在，所以其具有可扩展可定制的特性。kube-scheduler相当于整个集群的调度决策者，其通过预选和优选两个过程决定容器的最佳调度位置。
• kube-scheduler（调度器）的指责主要是为新创建的pod在集群中寻找最合适的node，并将pod调度到Node上
• 从集群所有节点中，根据调度算法挑选出所有可以运行该pod的节点
• 再根据调度算法从上述node节点选择最优节点作为最终结果
• Scheduler调度器运行在master节点，它的核心功能是监听apiserver来获取PodSpec.NodeName为空的pod，然后为pod创建一个binding指示pod应该调度到哪个节点上，调度结果写入apiserver

kube-scheduler主要职责

• 集群高可用：如果 kube-scheduler 设置了 leader-elect 选举启动参数，那么会通过 etcd 进行节点选主（ kube-scheduler 和 kube-controller-manager 都使用了一主多从的高可用方案）
• 调度资源监听：通过 list-Watch 机制监听 kube-apiserver 上资源的变化，这里的资源主要指的是 Pod 和 Node
• 调度节点分配：通过预选（Predicates）与优选（Priorites）策略，为待调度的 Pod 分配一个 Node 进行绑定并填充nodeName，同时将分配结果通过 kube-apiserver 写入 etcd

实验部署

实验环境

• Master01:192.168.80.12
• Node01:192.168.80.13
• Node02:192.168.80.14
• 本篇实验部署是接上篇文章Flannel部署的，所以实验环境不变，本次部署主要是部署master节点需要的组件

kube-APIserver组件部署

• master01服务器操作，配置apiserver自签证书

  [root@master01 k8s]# cd /mnt/           //进入宿主机挂载目录
  [root@master01 mnt]# ls
  etcd-cert     etcd-v3.3.10-linux-amd64.tar.gz     k8s-cert.sh                           master.zip
  etcd-cert.sh  flannel.sh                          kubeconfig.sh                         node.zip
  etcd.sh       flannel-v0.10.0-linux-amd64.tar.gz  kubernetes-server-linux-amd64.tar.gz
  [root@master01 mnt]# cp master.zip /root/k8s/      //复制压缩包到k8s工作目录
  [root@master01 mnt]# cd /root/k8s/             //进入k8s工作目录
  [root@master01 k8s]# ls
  cfssl.sh   etcd-v3.3.10-linux-amd64            kubernetes-server-linux-amd64.tar.gz
  etcd-cert  etcd-v3.3.10-linux-amd64.tar.gz     master.zip
  etcd.sh    flannel-v0.10.0-linux-amd64.tar.gz
  [root@master01 k8s]# unzip master.zip               //解压压缩包
  Archive:  master.zip
  inflating: apiserver.sh
  inflating: controller-manager.sh
  inflating: scheduler.sh
  [root@master01 k8s]# mkdir /opt/kubernetes/{cfg,bin,ssl} -p      //在master01中创建工作目录，之前在node节点中同样也创建过工作目录
  [root@master01 k8s]# mkdir k8s-cert        //创建自签证书目录
  [root@master01 k8s]# cp /mnt/k8s-cert.sh /root/k8s/k8s-cert    //将挂载的自签证书脚本移动到k8s工作目录中的自签证书目录
  [root@master01 k8s]# cd k8s-cert         //进入目录
  [root@master01 k8s-cert]# vim k8s-cert.sh     //编辑拷贝过来的脚本文件
  ...
  cat > server-csr.json <<EOF
  {
  "CN": "kubernetes",
  "hosts": [
    "10.0.0.1",
    "127.0.0.1",
    "192.168.80.12",          //更改地址为master01IP地址
    "192.168.80.11",          //添加地址为master02IP地址，为之后我们要做的多节点做准备
    "192.168.80.100",         //添加vrrp地址，为之后要做的负载均衡做准备
    "192.168.80.13",          //更改地址为node01节点IP地址
    "192.168.80.14",          //更改地址为node02节点IP地址
    "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
  ...
  :wq
  [root@master01 k8s-cert]# bash k8s-cert.sh      //执行脚本，生成证书
  2020/02/10 10:59:17 [INFO] generating a new CA key and certificate from CSR
  2020/02/10 10:59:17 [INFO] generate received request
  2020/02/10 10:59:17 [INFO] received CSR
  2020/02/10 10:59:17 [INFO] generating key: rsa-2048
  2020/02/10 10:59:17 [INFO] encoded CSR
  2020/02/10 10:59:17 [INFO] signed certificate with serial number 10087572098424151492431444614087300651068639826
  2020/02/10 10:59:17 [INFO] generate received request
  2020/02/10 10:59:17 [INFO] received CSR
  2020/02/10 10:59:17 [INFO] generating key: rsa-2048
  2020/02/10 10:59:17 [INFO] encoded CSR
  2020/02/10 10:59:17 [INFO] signed certificate with serial number 125779224158375570229792859734449149781670193528
  2020/02/10 10:59:17 [WARNING] This certificate lacks a "hosts" field. This makes it unsuitable for
  websites. For more information see the Baseline Requirements for the Issuance and Management
  of Publicly-Trusted Certificates, v.1.1.6, from the CA/Browser Forum (https://cabforum.org);
  specifically, section 10.2.3 ("Information Requirements").
  2020/02/10 10:59:17 [INFO] generate received request
  2020/02/10 10:59:17 [INFO] received CSR
  2020/02/10 10:59:17 [INFO] generating key: rsa-2048
  2020/02/10 10:59:17 [INFO] encoded CSR
  2020/02/10 10:59:17 [INFO] signed certificate with serial number 328087687681727386760831073265687413205940136472
  2020/02/10 10:59:17 [WARNING] This certificate lacks a "hosts" field. This makes it unsuitable for
  websites. For more information see the Baseline Requirements for the Issuance and Management
  of Publicly-Trusted Certificates, v.1.1.6, from the CA/Browser Forum (https://cabforum.org);
  specifically, section 10.2.3 ("Information Requirements").
  2020/02/10 10:59:17 [INFO] generate received request
  2020/02/10 10:59:17 [INFO] received CSR
  2020/02/10 10:59:17 [INFO] generating key: rsa-2048
  2020/02/10 10:59:18 [INFO] encoded CSR
  2020/02/10 10:59:18 [INFO] signed certificate with serial number 525069068228188747147886102005817997066385735072
  2020/02/10 10:59:18 [WARNING] This certificate lacks a "hosts" field. This makes it unsuitable for
  websites. For more information see the Baseline Requirements for the Issuance and Management
  of Publicly-Trusted Certificates, v.1.1.6, from the CA/Browser Forum (https://cabforum.org);
  specifically, section 10.2.3 ("Information Requirements").
  [root@master01 k8s-cert]# ls *pem       //查看  会生成8个证书
  admin-key.pem  admin.pem  ca-key.pem  ca.pem  kube-proxy-key.pem  kube-proxy.pem  server-key.pem  server.pem
  [root@master01 k8s-cert]# cp ca*pem server*pem /opt/kubernetes/ssl/   //将证书移动到k8s工作目录下ssl目录中

• 配置apiserver

  [root@master01 k8s-cert]# cd ..      //回到k8s工作目录
  [root@master01 k8s]# tar zxvf kubernetes-server-linux-amd64.tar.gz      //解压软件包
  kubernetes/
  kubernetes/server/
  kubernetes/server/bin/
  ...
  [root@master01 k8s]# cd kubernetes/server/bin/     //进入加压后软件命令存放目录
  [root@master01 bin]# ls
  apiextensions-apiserver              kube-apiserver.docker_tag           kube-proxy
  cloud-controller-manager             kube-apiserver.tar                  kube-proxy.docker_tag
  cloud-controller-manager.docker_tag  kube-controller-manager             kube-proxy.tar
  cloud-controller-manager.tar         kube-controller-manager.docker_tag  kube-scheduler
  hyperkube                            kube-controller-manager.tar         kube-scheduler.docker_tag
  kubeadm                              kubectl                             kube-scheduler.tar
  kube-apiserver                       kubelet                             mounter
  [root@master01 bin]# cp kube-apiserver kubectl kube-controller-manager kube-scheduler /opt/kubernetes/bin/          //复制关键命令文件到k8s工作目录的bin目录中
  [root@master01 bin]# cd /root/k8s/
  [root@master01 k8s]# head -c 16 /dev/urandom | od -An -t x | tr -d ' '      //生成一个序列号
  c37758077defd4033bfe95a071689272
  [root@master01 k8s]# vim /opt/kubernetes/cfg/token.csv           //创建token.csv文件，可以理解为创建一个管理性的角色
  c37758077defd4033bfe95a071689272,kubelet-bootstrap,10001,"system:kubelet-bootstrap"   //指定用户角色身份，前面的序列号使用生成的序列号
  :wq
  [root@master01 k8s]# bash apiserver.sh 192.168.80.12 https://192.168.80.12:2379,https://192.168.80.13:2379,https://192.168.80.14:2379    //二进制文件，token，证书都准备好，执行apiserver脚本，同时生成配置文件 
  Created symlink from /etc/systemd/system/multi-user.target.wants/kube-apiserver.service to /usr/lib/systemd/system/kube-apiserver.service.
  [root@master01 k8s]# ps aux | grep kube       //检查进程是否启动成功
  root      17088  8.7 16.7 402260 312192 ?       Ssl  11:17   0:08 /opt/kubernetes/bin/kube-apiserver --logtostderr=true --v=4 --etcd-servers=https://192.168.80.12:2379,https://192.168.80.13:2379,https://192.168.80.14:2379 --bind-address=192.168.80.12 --secure-port=6443 --advertise-address=192.168.80.12 --allow-privileged=true --service-cluster-ip-range=10.0.0.0/24 --enable-admission-plugins=NamespaceLifecycle,LimitRanger,ServiceAccount,ResourceQuota,NodeRestriction --authorization-mode=RBAC,Node --kubelet-https=true --enable-bootstrap-token-auth --token-auth-file=/opt/kubernetes/cfg/token.csv --service-node-port-range=30000-50000 --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/etcd/ssl/ca.pem --etcd-certfile=/opt/etcd/ssl/server.pem --etcd-keyfile=/opt/etcd/ssl/server-key.pem
  root      17101  0.0  0.0 112676   980 pts/0    S+   11:19   0:00 grep --color=auto kube
  [root@master01 k8s]# cat /opt/kubernetes/cfg/kube-apiserver    //查看生成的配置文件
  
  KUBE_APISERVER_OPTS="--logtostderr=true \
  --v=4 \
  --etcd-servers=https://192.168.80.12:2379,https://192.168.80.13:2379,https://192.168.80.14:2379 \
  --bind-address=192.168.80.12 \
  --secure-port=6443 \
  --advertise-address=192.168.80.12 \
  --allow-privileged=true \
  --service-cluster-ip-range=10.0.0.0/24 \
  --enable-admission-plugins=NamespaceLifecycle,LimitRanger,ServiceAccount,ResourceQuota,NodeRestriction \
  --authorization-mode=RBAC,Node \
  --kubelet-https=true \
  --enable-bootstrap-token-auth \
  --token-auth-file=/opt/kubernetes/cfg/token.csv \
  --service-node-port-range=30000-50000 \
  --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/etcd/ssl/ca.pem \
  --etcd-certfile=/opt/etcd/ssl/server.pem \
  --etcd-keyfile=/opt/etcd/ssl/server-key.pem"
  [root@master01 k8s]# netstat -ntap | grep 6443      //查看监听的端口是否开启
  tcp        0      0 192.168.80.12:6443      0.0.0.0:*               LISTEN      17088/kube-apiserve
  tcp        0      0 192.168.80.12:48320     192.168.80.12:6443      ESTABLISHED 17088/kube-apiserve
  tcp        0      0 192.168.80.12:6443      192.168.80.12:48320     ESTABLISHED 17088/kube-apiserve
  [root@master01 k8s]# netstat -ntap | grep 8080      //查看监听的端口是否开启
  tcp        0      0 127.0.0.1:8080          0.0.0.0:*               LISTEN      17088/kube-apiserve

• 配置scheduler服务

  [root@master01 k8s]# ./scheduler.sh 127.0.0.1       //直接执行脚本，启动服务，并生成配置文件即可
  Created symlink from /etc/systemd/system/multi-user.target.wants/kube-scheduler.service to /usr/lib/systemd/system/kube-scheduler.service.
  [root@master01 k8s]# systemctl status kube-scheduler.service      //查看服务运行状态
  ● kube-scheduler.service - Kubernetes Scheduler
  Loaded: loaded (/usr/lib/systemd/system/kube-scheduler.service; enabled; vendor preset: disabled)
  Active: active (running) since 一 2020-02-10 11:22:13 CST; 2min 46s ago     //成功运行
   Docs: https://github.com/kubernetes/kubernetes
   ...

• 配置controller-manager服务

  [root@master01 k8s]# chmod +x controller-manager.sh       //添加脚本执行权限
  [root@master01 k8s]# ./controller-manager.sh 127.0.0.1    //执行脚本，启动服务，并生成配置文件
  Created symlink from /etc/systemd/system/multi-user.target.wants/kube-controller-manager.service to /usr/lib/systemd/system/kube-controller-manager.service.
  [root@master01 k8s]# systemctl status kube-controller-manager.service     //查看运行状态
  ● kube-controller-manager.service - Kubernetes Controller Manager 
  Loaded: loaded (/usr/lib/systemd/system/kube-controller-manager.service; enabled; vendor preset: disabled)
  Active: active (running) since 一 2020-02-10 11:28:21 CST; 7min ago     //成功运行
  ...
  [root@master01 k8s]# /opt/kubernetes/bin/kubectl get cs      //查看节点运行状态
  NAME                 STATUS    MESSAGE             ERROR
  scheduler            Healthy   ok
  controller-manager   Healthy   ok
  etcd-2               Healthy   {"health":"true"}
  etcd-0               Healthy   {"health":"true"}
  etcd-1               Healthy   {"health":"true"}

  master节点组件部署完成

来源：51CTO

作者：SiceLc

链接：https://blog.51cto.com/14473285/2470025