305 lines
11 KiB
Markdown
305 lines
11 KiB
Markdown
# 部署高可用 kubernetes master 集群
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kubernetes master 节点包含的组件：
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+ kube-apiserver
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+ kube-scheduler
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+ kube-controller-manager
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目前这三个组件需要部署在同一台机器上。
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+ `kube-scheduler`、`kube-controller-manager` 和 `kube-apiserver` 三者的功能紧密相关；
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+ 同时只能有一个 `kube-scheduler`、`kube-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；
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本文档记录部署一个三个节点的高可用 kubernetes master 集群步骤。（后续创建一个 load balancer 来代理访问 kube-apiserver 的请求）
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## TLS 证书文件
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pem和token.csv证书文件我们在[TLS证书和秘钥](./01-TLS证书和秘钥.md)这一步中已经创建过了。我们再检查一下。
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``` bash
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$ ls /etc/kubernetes/ssl
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admin-key.pem admin.pem ca-key.pem ca.pem kube-proxy-key.pem kube-proxy.pem kubernetes-key.pem kubernetes.pem
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```
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## 下载最新版本的二进制文件
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有两种下载方式
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**方式一**
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从 [github release 页面](https://github.com/kubernetes/kubernetes/releases) 下载发布版 tarball，解压后再执行下载脚本
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``` shell
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$ wget https://github.com/kubernetes/kubernetes/releases/download/v1.6.0/kubernetes.tar.gz
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$ tar -xzvf kubernetes.tar.gz
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...
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$ cd kubernetes
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$ ./cluster/get-kube-binaries.sh
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...
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```
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**方式二**
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从 [`CHANGELOG`页面](https://github.com/kubernetes/kubernetes/blob/master/CHANGELOG.md) 下载 `client` 或 `server` tarball 文件
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`server` 的 tarball `kubernetes-server-linux-amd64.tar.gz` 已经包含了 `client`(`kubectl`) 二进制文件，所以不用单独下载`kubernetes-client-linux-amd64.tar.gz`文件；
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``` shell
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$ # wget https://dl.k8s.io/v1.6.0/kubernetes-client-linux-amd64.tar.gz
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$ wget https://dl.k8s.io/v1.6.0/kubernetes-server-linux-amd64.tar.gz
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$ tar -xzvf kubernetes-server-linux-amd64.tar.gz
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...
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$ cd kubernetes
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$ tar -xzvf kubernetes-src.tar.gz
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```
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将二进制文件拷贝到指定路径
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``` bash
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$ cp -r server/bin/{kube-apiserver,kube-controller-manager,kube-scheduler,kubectl,kube-proxy,kubelet} /root/local/bin/
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```
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## 配置和启动 kube-apiserver
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**创建 kube-apiserver的service配置文件**
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serivce配置文件`/usr/lib/systemd/system/kube-apiserver.service`内容：
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```ini
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[Unit]
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Description=Kubernetes API Service
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Documentation=https://github.com/GoogleCloudPlatform/kubernetes
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After=network.target
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After=etcd.service
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[Service]
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EnvironmentFile=-/etc/kubernetes/config
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EnvironmentFile=-/etc/kubernetes/apiserver
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ExecStart=/usr/bin/kube-apiserver \
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$KUBE_LOGTOSTDERR \
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$KUBE_LOG_LEVEL \
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$KUBE_ETCD_SERVERS \
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$KUBE_API_ADDRESS \
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$KUBE_API_PORT \
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$KUBELET_PORT \
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$KUBE_ALLOW_PRIV \
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$KUBE_SERVICE_ADDRESSES \
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$KUBE_ADMISSION_CONTROL \
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$KUBE_API_ARGS
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Restart=on-failure
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Type=notify
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LimitNOFILE=65536
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[Install]
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WantedBy=multi-user.target
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```
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`/etc/kubernetes/config`文件的内容为：
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```ini
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###
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# kubernetes system config
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#
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# The following values are used to configure various aspects of all
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# kubernetes services, including
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#
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# kube-apiserver.service
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# kube-controller-manager.service
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# kube-scheduler.service
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# kubelet.service
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# kube-proxy.service
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# logging to stderr means we get it in the systemd journal
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KUBE_LOGTOSTDERR="--logtostderr=true"
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# journal message level, 0 is debug
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KUBE_LOG_LEVEL="--v=0"
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# Should this cluster be allowed to run privileged docker containers
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KUBE_ALLOW_PRIV="--allow-privileged=true"
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# How the controller-manager, scheduler, and proxy find the apiserver
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#KUBE_MASTER="--master=http://sz-pg-oam-docker-test-001.tendcloud.com:8080"
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KUBE_MASTER="--master=http://172.20.0.113:8080"
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```
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该配置文件同时被kube-apiserver、kube-controller-manager、kube-scheduler、kubelet、kube-proxy使用。
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apiserver配置文件`/etc/kubernetes/apiserver`内容为：
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``` Ini
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###
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## kubernetes system config
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##
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## The following values are used to configure the kube-apiserver
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##
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#
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## The address on the local server to listen to.
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#KUBE_API_ADDRESS="--insecure-bind-address=sz-pg-oam-docker-test-001.tendcloud.com"
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KUBE_API_ADDRESS="--advertise-address=172.20.0.113 --bind-address=172.20.0.113 --insecure-bind-address=172.20.0.113"
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#
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## The port on the local server to listen on.
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#KUBE_API_PORT="--port=8080"
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#
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## Port minions listen on
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#KUBELET_PORT="--kubelet-port=10250"
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#
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## Comma separated list of nodes in the etcd cluster
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KUBE_ETCD_SERVERS="--etcd-servers=https://172.20.0.113:2379,172.20.0.114:2379,172.20.0.115:2379"
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#
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## Address range to use for services
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KUBE_SERVICE_ADDRESSES="--service-cluster-ip-range=10.254.0.0/16"
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#
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## default admission control policies
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KUBE_ADMISSION_CONTROL="--admission-control=ServiceAccount,NamespaceLifecycle,NamespaceExists,LimitRanger,ResourceQuota"
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#
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## Add your own!
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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 --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"
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```
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+ `--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；
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+ 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;
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+ 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；
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+ 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；
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+ 如果使用了 kubelet TLS Boostrap 机制，则不能再指定 `--kubelet-certificate-authority`、`--kubelet-client-certificate` 和 `--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；
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+ `--admission-control` 值必须包含 `ServiceAccount`；
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+ `--bind-address` 不能为 `127.0.0.1`；
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+ `runtime-config`配置为`rbac.authorization.k8s.io/v1beta1`，表示运行时的apiVersion；
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+ `--service-cluster-ip-range` 指定 Service Cluster IP 地址段，该地址段不能路由可达；
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+ 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；
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完整 unit 见 [kube-apiserver.service](./systemd/kube-apiserver.service)
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**启动kube-apiserver**
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``` bash
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$ systemctl daemon-reload
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$ systemctl enable kube-apiserver
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$ systemctl start kube-apiserver
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$ systemctl status kube-apiserver
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```
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## 配置和启动 kube-controller-manager
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**创建 kube-controller-manager的serivce配置文件**
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文件路径`/usr/lib/systemd/system/kube-controller-manager.service`
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```ini
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Description=Kubernetes Controller Manager
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Documentation=https://github.com/GoogleCloudPlatform/kubernetes
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[Service]
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EnvironmentFile=-/etc/kubernetes/config
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EnvironmentFile=-/etc/kubernetes/controller-manager
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ExecStart=/usr/bin/kube-controller-manager \
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$KUBE_LOGTOSTDERR \
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$KUBE_LOG_LEVEL \
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$KUBE_MASTER \
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$KUBE_CONTROLLER_MANAGER_ARGS
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Restart=on-failure
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LimitNOFILE=65536
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[Install]
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WantedBy=multi-user.target
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```
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配置文件`/etc/kubernetes/controller-manager`。
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``` ini
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###
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# The following values are used to configure the kubernetes controller-manager
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# defaults from config and apiserver should be adequate
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# Add your own!
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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"
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```
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+ `--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；
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+ `--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；
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+ `--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**；
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+ `--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：
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``` bash
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$ kubectl get componentstatuses
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NAME STATUS MESSAGE ERROR
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scheduler Unhealthy Get http://127.0.0.1:10251/healthz: dial tcp 127.0.0.1:10251: getsockopt: connection refused
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controller-manager Healthy ok
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etcd-2 Unhealthy Get http://172.20.0.113:2379/health: malformed HTTP response "\x15\x03\x01\x00\x02\x02"
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etcd-0 Healthy {"health": "true"}
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etcd-1 Healthy {"health": "true"}
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```
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参考：https://github.com/kubernetes-incubator/bootkube/issues/64
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完整 unit 见 [kube-controller-manager.service](./systemd/kube-controller-manager.service)
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### 启动 kube-controller-manager
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``` bash
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$ systemctl daemon-reload
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$ systemctl enable kube-controller-manager
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$ systemctl start kube-controller-manager
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```
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## 配置和启动 kube-scheduler
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**创建 kube-scheduler的serivce配置文件**
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文件路径`/usr/lib/systemd/system/kube-scheduler.serivce`。
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```ini
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[Unit]
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Description=Kubernetes Scheduler Plugin
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Documentation=https://github.com/GoogleCloudPlatform/kubernetes
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[Service]
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EnvironmentFile=-/etc/kubernetes/config
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EnvironmentFile=-/etc/kubernetes/scheduler
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ExecStart=/usr/bin/kube-scheduler \
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$KUBE_LOGTOSTDERR \
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$KUBE_LOG_LEVEL \
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$KUBE_MASTER \
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$KUBE_SCHEDULER_ARGS
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Restart=on-failure
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LimitNOFILE=65536
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[Install]
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WantedBy=multi-user.target
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```
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配置文件`/etc/kubernetes/scheduler`。
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``` Ini
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###
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# kubernetes scheduler config
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# default config should be adequate
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# Add your own!
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KUBE_SCHEDULER_ARGS="--leader-elect=true --address=127.0.0.1"
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```
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+ `--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；
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完整 unit 见 [kube-scheduler.service](./systemd/kube-scheduler.service)
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### 启动 kube-scheduler
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``` bash
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$ systemctl daemon-reload
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$ systemctl enable kube-scheduler
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$ systemctl start kube-scheduler
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```
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## 验证 master 节点功能
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``` bash
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$ kubectl get componentstatuses
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NAME STATUS MESSAGE ERROR
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scheduler Healthy ok
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controller-manager Healthy ok
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etcd-0 Healthy {"health": "true"}
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etcd-1 Healthy {"health": "true"}
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etcd-2 Healthy {"health": "true"}
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```
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