Docker实践(6)—CentOS7上部署Kubernetes

Kubernetes架构

Kubernetes的整体架构如下：

Master为主控节点，上面运行apiserver，scheduler，controller-manager等组件。Minion相当于工作节点，上面运行kubelet，proxy，cAdvisor以及最重要的docker等组件。下面来实际部署一下这套集群管理工具。

环境

yy1  10.193.6.35

yy2  10.193.6.36

yy1作为master，yy2作为minion。

# cat /etc/centos-release

CentOS Linux release 7.0.1406 (Core)

安装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=""

# 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=""

# 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,  is debug

KUBE_LOG_LEVEL=

# Should this cluster be allowed to run privleged docker containers

KUBE_ALLOW_PRIV="true"

启动yy1上相关服务

master上需要运行etcd，kube-apiserver，kube-controller-manager，kube-scheduler这4个进程。

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=""

 # 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,  is debug

 KUBE_LOG_LEVEL=

 # Should this cluster be allowed to run privleged docker containers

 KUBE_ALLOW_PRIV="true"

修改yy2 kubelet的配置

CentOS7上没有docker.socket服务，注释掉kubelet中对docker.socket的依赖。

/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

启动yy2上的相关服务

minion上需要运行kube-proxy，kubelet以及docker。

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

创建pod描述文件

创建一个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": ,

          "hostPort": 

        }]

      }]

    }

  },

  "labels": {

    "name": "apache"

  }

}

创建pod

通过客户端工具kubecfg提交任务给apiserver，由scheduler选择一个minion部署容。

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

I0925 ::26.768122  request.go:] Waiting for completion of /operations/

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服务会自动部署到机器yy2，yy2上的docker会自动下载image，然后启动apache服务。顺利的话，过一会儿，apache服务就会在yy2上起来。

[root@yy1 ~]# kubecfg list pods  

ID                  Image(s)            Host                Labels              Status

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

apache              fedora/apache       10.193.6.36/        name=apache         Running

可以尝试访问一下，

主要参考

https://github.com/GoogleCloudPlatform/kubernetes/blob/master/docs/getting-started-guides/fedora/fedora_manual_config.md

作者：YY哥 
出处：http://www.cnblogs.com/hustcat/ 
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