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-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
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/v1.6.0/kubernetes.tar.gz
$ tar -xzvf kubernetes.tar.gz
...
$ cd kubernetes
$ ./cluster/get-kube-binaries.sh
...
方式二
从 CHANGELOG
页面 下载 client
或 server
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
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
; -
--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 "\x15\x03\x01\x00\x02\x02"
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