Docker实践(6)—CentOS7上部署Kubernetes

浏览数：63 / 时间：2015年06月09日

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="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"

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

 1 # cat /etc/kubernetes/kubelet
 2 
 3 ###
 4 
 5 # kubernetes kublet (minion) config
 6 
 7  
 8 
 9 # The address for the info server to serve on
10 
11 MINION_ADDRESS="10.193.6.36"
12 
13  
14 
15 # The port for the info server to serve on
16 
17 MINION_PORT="10250"
18 
19  
20 
21 # You may leave this blank to use the actual hostname
22 
23 MINION_HOSTNAME="10.193.6.36"
24 
25  
26 
27 # cat /etc/kubernetes/config  
28 
29 ###
30 
31 # kubernetes system config
32 
33 #
34 
35 # The following values are used to configure various aspects of all
36 
37 # kubernetes services, including
38 
39 #
40 
41 #   kubernetes-apiserver.service
42 
43 #   kubernetes-controller-manager.service
44 
45 #   kubernetes-kubelet.service
46 
47 #   kubernetes-proxy.service
48 
49  
50 
51 # Comma seperated list of nodes in the etcd cluster
52 
53 KUBE_ETCD_SERVERS="http://10.193.6.35:4001"
54 
55  
56 
57 # logging to stderr means we get it in the systemd journal
58 
59 KUBE_LOGTOSTDERR="true"
60 
61  
62 
63 # journal message level, 0 is debug
64 
65 KUBE_LOG_LEVEL=0
66 
67  
68 
69 # Should this cluster be allowed to run privleged docker containers
70 
71 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

 1  [Unit]
 2 
 3 Description=Kubernetes Kubelet
 4 
 5 #After=docker.socket cadvisor.service
 6 
 7 After=cadvisor.service
 8 
 9 #Requires=docker.socket cadvisor.service
10 
11 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": 80,

          "hostPort": 80

        }]

      }]

    }

  },

  "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 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