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Docker實(shí)踐—CentOS7上部署Kubernetes詳解

更新時(shí)間：2017年01月16日 10:48:47 作者：YY哥

kubernetes作為docker的管理工具是由Google開源提供，但是kubernetes的安裝一直折磨著運(yùn)維人員，在這一系列的文章中我將會(huì)由kubernetes的安裝講起為大家介紹kubernetes的安裝使用等過(guò)程，也作為自己的學(xué)習(xí)筆記。

Kubernetes架構(gòu)

Kubernetes的整體架構(gòu)如下：

Master為主控節(jié)點(diǎn)，上面運(yùn)行apiserver，scheduler，controller-manager等組件。Minion相當(dāng)于工作節(jié)點(diǎn)，上面運(yùn)行kubelet，proxy，cAdvisor以及最重要的docker等組件。下面來(lái)實(shí)際部署一下這套集群管理工具。

環(huán)境

yy1 10.193.6.35

yy2 10.193.6.36

yy1作為master，yy2作為minion。

# cat /etc/centos-release

CentOS Linux release 7.0.1406 (Core)

安裝kubernetes

# curl https://copr.fedoraproject.org/coprs/eparis/kubernetes-epel-7/repo/epel-7/eparis-kubernetes-epel-7-epel-7.repo -o /etc/yum.repos.d/eparis-kubernetes-epel-7-epel-7.repo

# yum install kubernetes -y

配置yy1

# cat /etc/kubernetes/apiserver

###

# kubernetes system config

#

# The following values are used to configure the kubernetes-apiserver

#

 

# The address on the local server to listen to.

KUBE_API_ADDRESS="10.193.6.35"

 

# The port on the local server to listen on.

KUBE_API_PORT="8080"

 

# How the replication controller and scheduler find the apiserver

KUBE_MASTER="10.193.6.35:8080"

 

# Comma seperated list of minions

MINION_ADDRESSES="10.193.6.36"

 

# Port minions listen on

MINION_PORT="10250"

 

# cat /etc/kubernetes/config

###

# kubernetes system config

#

# The following values are used to configure various aspects of all

# kubernetes services, including

#

#  kubernetes-apiserver.service

#  kubernetes-controller-manager.service

#  kubernetes-kubelet.service

#  kubernetes-proxy.service

 

# Comma seperated list of nodes in the etcd cluster

KUBE_ETCD_SERVERS="http://10.193.6.35:4001"

 

# logging to stderr means we get it in the systemd journal

KUBE_LOGTOSTDERR="true"

 

# journal message level, 0 is debug

KUBE_LOG_LEVEL=0

 

# Should this cluster be allowed to run privleged docker containers

KUBE_ALLOW_PRIV="true"

啟動(dòng)yy1上相關(guān)服務(wù)

master上需要運(yùn)行etcd，kube-apiserver，kube-controller-manager，kube-scheduler這4個(gè)進(jìn)程。

for SERVICES in etcd kube-apiserver kube-controller-manager kube-scheduler; do

  systemctl restart $SERVICES

  systemctl enable $SERVICES

  systemctl status $SERVICES

done

配置yy2

# cat /etc/kubernetes/kubelet

###

# kubernetes kublet (minion) config

 

# The address for the info server to serve on

MINION_ADDRESS="10.193.6.36"

 

# The port for the info server to serve on

MINION_PORT="10250"

# You may leave this blank to use the actual hostname

MINION_HOSTNAME="10.193.6.36"

# cat /etc/kubernetes/config 

###

# kubernetes system config

#

# The following values are used to configure various aspects of all

# kubernetes services, including

#

#  kubernetes-apiserver.service

#  kubernetes-controller-manager.service

#  kubernetes-kubelet.service

#  kubernetes-proxy.service

# Comma seperated list of nodes in the etcd cluster

KUBE_ETCD_SERVERS="http://10.193.6.35:4001"

 

# logging to stderr means we get it in the systemd journal

KUBE_LOGTOSTDERR="true"

# journal message level, 0 is debug

KUBE_LOG_LEVEL=0

# Should this cluster be allowed to run privleged docker containers

KUBE_ALLOW_PRIV="true"

修改yy2 kubelet的配置

CentOS7上沒(méi)有docker.socket服務(wù)，注釋掉kubelet中對(duì)docker.socket的依賴。

/usr/lib/systemd/system/kubelet.service

[Unit]

Description=Kubernetes Kubelet

#After=docker.socket cadvisor.service

After=cadvisor.service

#Requires=docker.socket cadvisor.service

Requires=cadvisor.service

啟動(dòng)yy2上的相關(guān)服務(wù)

minion上需要運(yùn)行kube-proxy，kubelet以及docker。

for SERVICES in kube-proxy kubelet docker; do 
  systemctl restart $SERVICES
  systemctl enable $SERVICES
  systemctl status $SERVICES 
done

創(chuàng)建pod描述文件

創(chuàng)建一個(gè)apache的pod描述文件。

# cat apache.json

{

 "id": "apache",

 "desiredState": {

  "manifest": {

   "version": "v1beta1",

   "id": "apache-1",

   "containers": [{

    "name": "master",

    "image": "fedora/apache",

    "ports": [{

     "containerPort": 80,

     "hostPort": 80

    }]

   }]

  }

 },

 "labels": {

  "name": "apache"

 }

}

創(chuàng)建pod

通過(guò)客戶端工具kubecfg提交任務(wù)給apiserver，由scheduler選擇一個(gè)minion部署容。

[root@yy1 ~]# kubecfg -c apache.json create pods

I0925 06:43:26.768122 09313 request.go:292] Waiting for completion of /operations/1

ID         Image(s)      Host        Labels       Status

----------     ----------     ----------     ----------     ----------

apache       fedora/apache    /          name=apache     Waiting

 

[root@yy1 ~]# kubecfg list pods 

ID         Image(s)      Host        Labels       Status

----------     ----------     ----------     ----------     ----------

apache       fedora/apache    10.193.6.36/    name=apache     Waiting

apache服務(wù)會(huì)自動(dòng)部署到機(jī)器yy2，yy2上的docker會(huì)自動(dòng)下載image，然后啟動(dòng)apache服務(wù)。順利的話，過(guò)一會(huì)兒，apache服務(wù)就會(huì)在yy2上起來(lái)。

[root@yy1 ~]# kubecfg list pods 

ID         Image(s)      Host        Labels       Status

----------     ----------     ----------     ----------     ----------

apache       fedora/apache    10.193.6.36/    name=apache     Running

NewImage