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  • 06-搭建master集群

    部署高可用 kubernetes master 集群

    kubernetes master 节点包含的组件:

    • kube-apiserver
    • kube-scheduler
    • kube-controller-manager

    目前这三个组件需要部署在同一台机器上。

    • kube-schedulerkube-controller-managerkube-apiserver 三者的功能紧密相关;
    • 同时只能有一个 kube-schedulerkube-controller-manager 进程处于工作状态,如果运行多个,则需要通过选举产生一个 leader;

    本文档现只记录部署一个 master 节点集群步骤。(后续创建一个有三个master节点的高可用集群,使用 load balancer 来代理访问 kube-apiserver 的请求,敬请期待~)

    TLS 证书文件

    pem和token.csv证书文件我们在之前的步骤中已经创建过了,我们再检查一下。

    # ls /etc/kubernetes/ssl
    admin-key.pem  admin.pem  ca-key.pem  ca.pem  kube-proxy-key.pem  kube-proxy.pem  kubernetes-key.pem  kubernetes.pem
    # ll /etc/kubernetes/token.csv 
    -rw-r--r-- 1 root root 84 Jul 19 13:29 /etc/kubernetes/token.csv
    
    

    下载最新版本的二进制文件

    有两种下载方式

    方式一

    github release 页面 下载发布版 tarball,解压后再执行下载脚本

    $ wget https://github.com/kubernetes/kubernetes/releases/download/v1.6.0/kubernetes.tar.gz
    $ tar -xzvf kubernetes.tar.gz
    ...
    $ cd kubernetes
    $ ./cluster/get-kube-binaries.sh
    ...
    

    方式二

    CHANGELOG页面 下载 clientserver tarball 文件

    # # wget https://dl.k8s.io/v1.6.2/kubernetes-client-linux-amd64.tar.gz
    # wget https://dl.k8s.io/v1.6.2/kubernetes-server-linux-amd64.tar.gz
    # tar -xzvf kubernetes-server-linux-amd64.tar.gz
    ...
    

    将二进制文件拷贝到指定路径

    # cp -r server/bin/{kube-apiserver,kube-controller-manager,kube-scheduler,kubectl,kube-proxy,kubelet} /usr/bin/
    

    配置和启动 kube-apiserver

    创建 kube-apiserver的service配置文件

    serivce配置文件/etc/systemd/system/kube-apiserver.service内容:

    [Unit]
    Description=Kubernetes API Service
    Documentation=https://github.com/GoogleCloudPlatform/kubernetes
    After=network.target
    After=etcd.service
    
    [Service]
    EnvironmentFile=-/etc/kubernetes/config
    EnvironmentFile=-/etc/kubernetes/apiserver
    ExecStart=/usr/bin/kube-apiserver 
    	    $KUBE_LOGTOSTDERR 
    	    $KUBE_LOG_LEVEL 
    	    $KUBE_ETCD_SERVERS 
    	    $KUBE_API_ADDRESS 
    	    $KUBE_API_PORT 
    	    $KUBELET_PORT 
    	    $KUBE_ALLOW_PRIV 
    	    $KUBE_SERVICE_ADDRESSES 
    	    $KUBE_ADMISSION_CONTROL 
    	    $KUBE_API_ARGS
    Restart=on-failure
    Type=notify
    LimitNOFILE=65536
    
    [Install]
    WantedBy=multi-user.target
    

    /etc/kubernetes/config文件的内容为:

    ###
    # kubernetes system config
    #
    # The following values are used to configure various aspects of all
    # kubernetes services, including
    #
    #   kube-apiserver.service
    #   kube-controller-manager.service
    #   kube-scheduler.service
    #   kubelet.service
    #   kube-proxy.service
    # logging to stderr means we get it in the systemd journal
    KUBE_LOGTOSTDERR="--logtostderr=true"
    
    # journal message level, 0 is debug
    KUBE_LOG_LEVEL="--v=0"
    
    # Should this cluster be allowed to run privileged docker containers
    KUBE_ALLOW_PRIV="--allow-privileged=true"
    
    # How the controller-manager, scheduler, and proxy find the apiserver
    #KUBE_MASTER="--master=http://sz-pg-oam-docker-test-001.tendcloud.com:8080"
    KUBE_MASTER="--master=http://192.168.1.121:8080"
    
    

    该配置文件同时被kube-apiserver、kube-controller-manager、kube-scheduler、kubelet、kube-proxy使用。

    apiserver配置文件/etc/kubernetes/apiserver内容为:

    ###
    ## kubernetes system config
    ##
    ## The following values are used to configure the kube-apiserver
    ##
    #
    ## The address on the local server to listen to.
    KUBE_API_ADDRESS="--advertise-address=192.168.1.121 --bind-address=192.168.1.121 --insecure-bind-address=192.168.1.121"
    #
    ## The port on the local server to listen on.
    #KUBE_API_PORT="--port=8080"
    #
    ## Port minions listen on
    #KUBELET_PORT="--kubelet-port=10250"
    #
    ## Comma separated list of nodes in the etcd cluster
    KUBE_ETCD_SERVERS="--etcd-servers=https://192.168.1.121:2379,192.168.1.122:2379,192.168.1.123:2379"
    #
    ## Address range to use for services
    KUBE_SERVICE_ADDRESSES="--service-cluster-ip-range=10.254.0.0/16"
    #
    ## default admission control policies
    KUBE_ADMISSION_CONTROL="--admission-control=ServiceAccount,NamespaceLifecycle,NamespaceExists,LimitRanger,ResourceQuota"
    #
    ## Add your own!
    KUBE_API_ARGS="--authorization-mode=RBAC --runtime-config=rbac.authorization.k8s.io/v1beta1 --kubelet-https=true --experimental-bootstrap-token-auth --token-auth-file=/etc/kubernetes/token.csv --service-node-port-range=30000-32767 --tls-cert-file=/etc/kubernetes/ssl/kubernetes.pem --tls-private-key-file=/etc/kubernetes/ssl/kubernetes-key.pem --client-ca-file=/etc/kubernetes/ssl/ca.pem --service-account-key-file=/etc/kubernetes/ssl/ca-key.pem --etcd-cafile=/etc/kubernetes/ssl/ca.pem --etcd-certfile=/etc/kubernetes/ssl/kubernetes.pem --etcd-keyfile=/etc/kubernetes/ssl/kubernetes-key.pem --enable-swagger-ui=true --allow-privileged=true --apiserver-count=3 --audit-log-maxage=30 --audit-log-maxbackup=3 --audit-log-maxsize=100 --audit-log-path=/var/lib/audit.log --event-ttl=1h"
    
    • --authorization-mode=RBAC 指定在安全端口使用 RBAC 授权模式,拒绝未通过授权的请求;
    • kube-scheduler、kube-controller-manager 一般和 kube-apiserver 部署在同一台机器上,它们使用非安全端口和 kube-apiserver通信;
    • kubelet、kube-proxy、kubectl 部署在其它 Node 节点上,如果通过安全端口访问 kube-apiserver,则必须先通过 TLS 证书认证,再通过 RBAC 授权;
    • kube-proxy、kubectl 通过在使用的证书里指定相关的 User、Group 来达到通过 RBAC 授权的目的;
    • 如果使用了 kubelet TLS Boostrap 机制,则不能再指定 --kubelet-certificate-authority--kubelet-client-certificate--kubelet-client-key 选项,否则后续 kube-apiserver 校验 kubelet 证书时出现 ”x509: certificate signed by unknown authority“ 错误;
    • --admission-control 值必须包含 ServiceAccount
    • --bind-address 不能为 127.0.0.1
    • runtime-config配置为rbac.authorization.k8s.io/v1beta1,表示运行时的apiVersion;
    • --service-cluster-ip-range 指定 Service Cluster IP 地址段,该地址段不能路由可达;
    • 缺省情况下 kubernetes 对象保存在 etcd /registry 路径下,可以通过 --etcd-prefix 参数进行调整;

    完整 unit 见 kube-apiserver.service

    启动kube-apiserver

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

    配置和启动 kube-controller-manager

    创建 kube-controller-manager的serivce配置文件

    文件路径/etc/systemd/system/kube-controller-manager.service

    Description=Kubernetes Controller Manager
    Documentation=https://github.com/GoogleCloudPlatform/kubernetes
    
    [Service]
    EnvironmentFile=-/etc/kubernetes/config
    EnvironmentFile=-/etc/kubernetes/controller-manager
    ExecStart=/usr/bin/kube-controller-manager 
    	    $KUBE_LOGTOSTDERR 
    	    $KUBE_LOG_LEVEL 
    	    $KUBE_MASTER 
    	    $KUBE_CONTROLLER_MANAGER_ARGS
    Restart=on-failure
    LimitNOFILE=65536
    
    [Install]
    WantedBy=multi-user.target
    
    

    配置文件/etc/kubernetes/controller-manager

    ###
    # The following values are used to configure the kubernetes controller-manager
    
    # defaults from config and apiserver should be adequate
    
    # Add your own!
    KUBE_CONTROLLER_MANAGER_ARGS="--address=127.0.0.1 --service-cluster-ip-range=10.254.0.0/16 --cluster-name=kubernetes --cluster-signing-cert-file=/etc/kubernetes/ssl/ca.pem --cluster-signing-key-file=/etc/kubernetes/ssl/ca-key.pem  --service-account-private-key-file=/etc/kubernetes/ssl/ca-key.pem --root-ca-file=/etc/kubernetes/ssl/ca.pem --leader-elect=true"
    
    • --service-cluster-ip-range 参数指定 Cluster 中 Service 的CIDR范围,该网络在各 Node 间必须路由不可达,必须和 kube-apiserver 中的参数一致;

    • --cluster-signing-* 指定的证书和私钥文件用来签名为 TLS BootStrap 创建的证书和私钥;

    • --root-ca-file 用来对 kube-apiserver 证书进行校验,指定该参数后,才会在Pod 容器的 ServiceAccount 中放置该 CA 证书文件

    • --address 值必须为 127.0.0.1,因为当前 kube-apiserver 期望 scheduler 和 controller-manager 在同一台机器,否则会报:

      $ kubectl get componentstatuses
      NAME                 STATUS      MESSAGE                                                                                        ERROR
      scheduler            Unhealthy   Get http://127.0.0.1:10251/healthz: dial tcp 127.0.0.1:10251: getsockopt: connection refused   
      controller-manager   Healthy     ok                                                                                             
      etcd-2               Unhealthy   Get http://172.20.0.113:2379/health: malformed HTTP response "x15x03x01x00x02x02"        
      etcd-0               Healthy     {"health": "true"}                                                                             
      etcd-1               Healthy     {"health": "true"}  
      

      参考:https://github.com/kubernetes-incubator/bootkube/issues/64

    完整 unit 见 kube-controller-manager.service

    启动 kube-controller-manager

    # systemctl daemon-reload
    # systemctl enable kube-controller-manager
    # systemctl start kube-controller-manager
    

    配置和启动 kube-scheduler

    创建 kube-scheduler的serivce配置文件

    文件路径/usr/lib/systemd/system/kube-scheduler.serivce

    [Unit]
    Description=Kubernetes Scheduler Plugin
    Documentation=https://github.com/GoogleCloudPlatform/kubernetes
    
    [Service]
    EnvironmentFile=-/etc/kubernetes/config
    EnvironmentFile=-/etc/kubernetes/scheduler
    ExecStart=/usr/bin/kube-scheduler 
    	    $KUBE_LOGTOSTDERR 
    	    $KUBE_LOG_LEVEL 
    	    $KUBE_MASTER 
    	    $KUBE_SCHEDULER_ARGS
    Restart=on-failure
    LimitNOFILE=65536
    
    [Install]
    WantedBy=multi-user.target
    
    

    配置文件/etc/kubernetes/scheduler

    ###
    # kubernetes scheduler config
    
    # default config should be adequate
    
    # Add your own!
    KUBE_SCHEDULER_ARGS="--leader-elect=true --address=127.0.0.1"
    
    
    • --address 值必须为 127.0.0.1,因为当前 kube-apiserver 期望 scheduler 和 controller-manager 在同一台机器;

    完整 unit 见 kube-scheduler.service

    启动 kube-scheduler

    # systemctl daemon-reload
    # systemctl enable kube-scheduler
    # systemctl start kube-scheduler
    

    验证 master 节点功能

    # kubectl  cluster-info
    Kubernetes master is running at https://192.168.1.121:6443
    
    To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.  
    
    • 可以使用浏览器访问192.168.1.121:8080查看是否正常
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  • 原文地址:https://www.cnblogs.com/guigujun/p/8366537.html
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