部署 master 节点
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-scheduler
、kube-controller-manager
和kube-apiserver
三者的功能紧密相关;- 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;
本文档介绍部署单机 kubernetes master 节点的步骤,没有实现高可用 master 集群。
计划后续再介绍部署 LB 的步骤,客户端 (kubectl、kubelet、kube-proxy) 使用 LB 的 VIP 来访问 kube-apiserver,从而实现高可用 master 集群。
master 节点与 node 节点上的 Pods 通过 Pod 网络通信,所以需要在 master 节点上部署 Flannel 网络。
使用的变量
本文档用到的变量定义如下:
$ export MASTER_IP=192.168.202.131 # 替换为当前部署的 master 机器 IP
$ # 导入用到的其它全局变量:SERVICE_CIDR、CLUSTER_CIDR、NODE_PORT_RANGE、ETCD_ENDPOINTS、BOOTSTRAP_TOKEN
$ source /root/local/bin/environment.sh
$
下载最新版本的二进制文件
有两种下载方式:
从 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/v1.6.2/kubernetes.tar.gz $ tar -xzvf kubernetes.tar.gz ... $ cd kubernetes $ ./cluster/get-kube-binaries.sh ...
从
CHANGELOG
页面 下载client
或server
tarball 文件server
的 tarballkubernetes-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;$ # 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 ... $ cd kubernetes $ tar -xzvf kubernetes-src.tar.gz
将二进制文件拷贝到指定路径:
$ sudo cp -r server/bin/{kube-apiserver,kube-controller-manager,kube-scheduler,kubectl,kube-proxy,kubelet} /root/local/bin/
$
安装和配置 flanneld
创建 kubernetes 证书
创建 kubernetes 证书签名请求
$ cat > kubernetes-csr.json <<EOF
{
"CN": "kubernetes",
"hosts": [
"127.0.0.1",
"${MASTER_IP}",
"10.254.0.1",
"kubernetes",
"kubernetes.default",
"kubernetes.default.svc",
"kubernetes.default.svc.cluster",
"kubernetes.default.svc.cluster.local"
],
"key": {
"algo": "rsa",
"size": 2048
},
"names": [
{
"C": "CN",
"ST": "BeiJing",
"L": "BeiJing",
"O": "k8s",
"OU": "System"
}
]
}
EOF
- 如果 hosts 字段不为空则需要指定授权使用该证书的 IP 或域名列表,所以上面分别指定了当前部署的 master 节点主机 IP;
还需要添加 kube-apiserver 注册的名为
kubernetes
的服务 IP (Service Cluster IP),一般是 kube-apiserver--service-cluster-ip-range
选项值指定的网段的第一个IP,如 "10.254.0.1";$ kubectl get svc kubernetes NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes 10.254.0.1 <none> 443/TCP 1d
生成 kubernetes 证书和私钥
$ cfssl gencert -ca=/etc/kubernetes/ssl/ca.pem \
-ca-key=/etc/kubernetes/ssl/ca-key.pem \
-config=/etc/kubernetes/ssl/ca-config.json \
-profile=kubernetes kubernetes-csr.json | cfssljson -bare kubernetes
$ ls kubernetes*
kubernetes.csr kubernetes-csr.json kubernetes-key.pem kubernetes.pem
$ sudo mkdir -p /etc/kubernetes/ssl/
$ sudo mv kubernetes*.pem /etc/kubernetes/ssl/
$ rm kubernetes.csr kubernetes-csr.json
配置和启动 kube-apiserver
创建 kube-apiserver 使用的客户端 token 文件
kubelet 首次启动时向 kube-apiserver 发送 TLS Bootstrapping 请求,kube-apiserver 验证 kubelet 请求中的 token 是否与它配置的 token.csv 一致,如果一致则自动为 kubelet生成证书和秘钥。
$ # 导入的 environment.sh 文件定义了 BOOTSTRAP_TOKEN 变量
$ cat > token.csv <<EOF
${BOOTSTRAP_TOKEN},kubelet-bootstrap,10001,"system:kubelet-bootstrap"
EOF
$ mv token.csv /etc/kubernetes/
$
创建 kube-apiserver 的 systemd unit 文件
$ cat kube-apiserver.service
[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://192.168.202.131:8080"
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="--insecure-bind-address=sz-pg-oam-docker-test-001.tendcloud.com"
KUBE_API_ADDRESS="--advertise-address=192.168.202.131 --bind-address=192.168.202.131 --insecure-bind-address=192.168.202.131"
#
## 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://192.168.202.131:2379,192.168.202.132:2379,192.168.202.133:2379"
#
## 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 --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"
- kube-apiserver 1.6 版本开始使用 etcd v3 API 和存储格式;
--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
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; --admission-control
值必须包含ServiceAccount
,否则部署集群插件时会失败;--bind-address
不能为127.0.0.1
;--service-cluster-ip-range
指定 Service Cluster IP 地址段,该地址段不能路由可达;--service-node-port-range
指定 NodePort 的端口范围;- 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
$ sudo cp kube-apiserver.service /etc/systemd/system/
$ sudo systemctl daemon-reload
$ sudo systemctl enable kube-apiserver
$ sudo systemctl start kube-apiserver
$ sudo systemctl status kube-apiserver
$
配置和启动 kube-controller-manager
创建 kube-controller-manager 的 systemd unit 文件
$ cat kube-controller-manager.service
[Unit]
Description=Kubernetes Controller Manager
Documentation=https://github.com/GoogleCloudPlatform/kubernetes
After=kube-apiserver.service
[Service]
EnvironmentFile=-/etc/kubernetes/config
EnvironmentFile=-/etc/kubernetes/controller-manager
ExecStart=/usr/bin/kube-controller-manager \
$KUBE_LOGTOSTDERR \
$KUBE_LOG_LEVEL \
$KUBE_MASTER \
$KUBE_CONTROLLER_MANAGER_ARGS
Restart=on-failure
LimitNOFILE=65536
[Install]
WantedBy=multi-user.target
配置文件/etc/kubernetes/controller-manager
###
# The following values are used to configure the kubernetes controller-manager
# defaults from config and apiserver should be adequate
# Add your own!
KUBE_CONTROLLER_MANAGER_ARGS="--address=127.0.0.1 --service-cluster-ip-range=10.254.0.0/16 --cluster-name=kubernetes --cluster-signing-cert-file=/etc/kubernetes/ssl/ca.pem --cluster-signing-key-file=/etc/kubernetes/ssl/ca-key.pem --service-account-private-key-file=/etc/kubernetes/ssl/ca-key.pem --root-ca-file=/etc/kubernetes/ssl/ca.pem --leader-elect=true"
--address
值必须为127.0.0.1
,因为当前 kube-apiserver 期望 scheduler 和 controller-manager 在同一台机器,否则:$ kubectl get componentstatuses NAME STATUS MESSAGE ERROR controller-manager Unhealthy Get http://127.0.0.1:10252/healthz: dial tcp 127.0.0.1:10252: getsockopt: connection refused scheduler Unhealthy Get http://127.0.0.1:10251/healthz: dial tcp 127.0.0.1:10251: getsockopt: connection refused
参考:https://github.com/kubernetes-incubator/bootkube/issues/64
--master=http://{MASTER_IP}:8080
:使用非安全 8080 端口与 kube-apiserver 通信;--cluster-cidr
指定 Cluster 中 Pod 的 CIDR 范围,该网段在各 Node 间必须路由可达(flanneld保证);--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;--leader-elect=true
部署多台机器组成的 master 集群时选举产生一处于工作状态的kube-controller-manager
进程;
完整 unit 见 kube-controller-manager.service
启动 kube-controller-manager
$ sudo cp kube-controller-manager.service /etc/systemd/system/
$ sudo systemctl daemon-reload
$ sudo systemctl enable kube-controller-manager
$ sudo systemctl start kube-controller-manager
$
配置和启动 kube-scheduler
创建 kube-scheduler 的 systemd unit 文件
$ cat kube-scheduler.service
[Unit]
Description=Kubernetes Scheduler
Documentation=https://github.com/GoogleCloudPlatform/kubernetes
After=kube-apiserver.service
[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;--master=http://{MASTER_IP}:8080
:使用非安全 8080 端口与 kube-apiserver 通信;--leader-elect=true
部署多台机器组成的 master 集群时选举产生一处于工作状态的kube-controller-manager
进程;
完整 unit 见 kube-scheduler.service。
启动 kube-scheduler
$ sudo cp kube-scheduler.service /etc/systemd/system/
$ sudo systemctl daemon-reload
$ sudo systemctl enable kube-scheduler
$ sudo systemctl start kube-scheduler
$
验证 master 节点功能
$ kubectl get componentstatuses
NAME STATUS MESSAGE ERROR
controller-manager Healthy ok
scheduler Healthy ok
etcd-0 Healthy {"health": "true"}
etcd-1 Healthy {"health": "true"}
etcd-2 Healthy {"health": "true"}