Kubernetes集群初探

上文我们在一台虚机上演示了Kubernetes基于redis和docker的guestbook留言簿案例，本文我们将通过配置Kubernetes集群的方式继续深入研究。集群组件安装如下配置。

IP	NAME	Component
192.168.56.103	centos-master	etcd,kube-apiserver,kube-controller-manager,kube-scheduler
192.168.56.105	centos-node01	kube-proxy,kubelet,docker
192.168.56.107	centos-node02	kube-proxy,kubelet,docker

主机环境：centos 7，三台虚机。

1.准备工作
以下工作在每台虚机执行。
1.1 停止防火墙
#systemctl disable firewalld
#systemctl stop firewalld

1.2 修改iptables

yum install iptables-services
vi /etc/sysconfig/iptables把icmp-host-prohibited两条注释掉

# sample configuration for iptables service
# you can edit this manually or use system-config-firewall
# please do not ask us to add additional ports/services to this default configuration
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT
#-A INPUT -j REJECT --reject-with icmp-host-prohibited
#-A FORWARD -j REJECT --reject-with icmp-host-prohibited
COMMIT

重启iptables
#systemctl restart iptables

1.3 使用阿里镜像(或other)
#wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo

1.4 更新主机列表

#echo "192.168.56.103 CentOS7.2  

192.168.56.105 CentOS7-1 

192.168.56.107 CentOS7-2"  >> /etc/hosts

2.安装配置kubernetes master
2.1 在centos-master上安装
#yum install kubernetes-master
#yum install etcd

2.2配置 Kubernetes services
#vi /etc/kubernetes/config

#### 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 journalKUBE_LOGTOSTDERR="--logtostderr=true"# journal message level, 0 is debugKUBE_LOG_LEVEL="--v=0"# Should this cluster be allowed to run privileged docker containersKUBE_ALLOW_PRIV="--allow-privileged=false"# How the controller-manager, scheduler, and proxy find the apiserverKUBE_MASTER="--master=http://centos-master:8080"

2.3配置Kubernetes API server
#vi /etc/kubernetes/apiserver

#### 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=0.0.0.0"# The port on the local server to listen on.KUBE_API_PORT="--insecure-port=8080"# Port minions listen on#KUBELET_PORT="--kubelet-port=10250"# Comma separated list of nodes in the etcd clusterKUBE_ETCD_SERVERS="--etcd-servers=http://127.0.0.1:2379"# Address range to use for servicesKUBE_SERVICE_ADDRESSES="--service-cluster-ip-range=10.254.0.0/16"# default admission control policiesKUBE_ADMISSION_CONTROL="--admission-control=NamespaceLifecycle,NamespaceExists,LimitRanger,SecurityContextDeny,ResourceQuota"# Add your own!KUBE_API_ARGS=""

2.4 启动服务

for SERVICES in etcd kube-apiserver kube-controller-manager kube-scheduler; do     systemctl restart $SERVICES    systemctl enable $SERVICES    systemctl status $SERVICES done

2.5 停止服务

for SERVICES in etcd kube-apiserver kube-controller-manager kube-scheduler; do 
    systemctl stop $SERVICES
done

3.安装配置kubernetes node
3.1 在centos-node01及centos-node02上安装
#yum install kubernetes-node
#vi /etc/kubernetes/config

#### 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 journalKUBE_LOGTOSTDERR="--logtostderr=true"# journal message level, 0 is debugKUBE_LOG_LEVEL="--v=0"# Should this cluster be allowed to run privileged docker containersKUBE_ALLOW_PRIV="--allow-privileged=false"# How the controller-manager, scheduler, and proxy find the apiserverKUBE_MASTER="--master=http://centos-master:8080"

3.2 配置 kubelet文件
vi /etc/kubernetes/kubelet
centos-node01

#### kubernetes kubelet (minion) config# The address for the info server to serve on (set to 0.0.0.0 or "" for all interfaces)KUBELET_ADDRESS="--address=0.0.0.0"# The port for the info server to serve onKUBELET_PORT="--port=10250"# You may leave this blank to use the actual hostnameKUBELET_HOSTNAME="--hostname-override=centos-minion01"# location of the api-serverKUBELET_API_SERVER="--api-servers=http://centos-master:8080"# pod infrastructure containerKUBELET_POD_INFRA_CONTAINER="--pod-infra-container-image=registry.access.redhat.com/rhel7/pod-infrastructure:latest"# Add your own!KUBELET_ARGS=""

centos-node02

###
# kubernetes kubelet (minion) config# The address for the info server to serve on (set to 0.0.0.0 or "" for all interfaces)KUBELET_ADDRESS="--address=0.0.0.0"# The port for the info server to serve onKUBELET_PORT="--port=10250"# You may leave this blank to use the actual hostnameKUBELET_HOSTNAME="--hostname-override=centos-minion02"# location of the api-serverKUBELET_API_SERVER="--api-servers=http://centos-master:8080"# pod infrastructure containerKUBELET_POD_INFRA_CONTAINER="--pod-infra-container-image=registry.access.redhat.com/rhel7/pod-infrastructure:latest"# Add your own!KUBELET_ARGS=""

3.3 配置config文件

     vi /etc/kubernetes/config

#### 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 journalKUBE_LOGTOSTDERR="--logtostderr=true"# journal message level, 0 is debugKUBE_LOG_LEVEL="--v=0"# Should this cluster be allowed to run privileged docker containersKUBE_ALLOW_PRIV="--allow-privileged=false"# How the controller-manager, scheduler, and proxy find the apiserverKUBE_MASTER="--master=http://centos-master:8080"

3.4 启动服务

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

在centos-node01上启动

[root@centos-minion01 ~]# for SERVICES in kube-proxy kubelet docker; do>     systemctl restart $SERVICES>     systemctl enable $SERVICES>     systemctl status $SERVICES> done

在centos-minion02上启动

[root@centos-minion02 kubernetes]# for SERVICES in kube-proxy kubelet docker; do>     systemctl restart $SERVICES>     systemctl enable $SERVICES>     systemctl status $SERVICES> done

3.5 停止服务

for SERVICES in kube-proxy kubelet docker; do     systemctl stop $SERVICES done

4. 检查及确认状态
#kubectl get nodes
#kubectl cluster-info
我们看到2个节点都正常启动。

[root@CentOS7 yum.repos.d]# kubectl get nodes
NAME        LABELS                                          STATUS    AGE
127.0.0.1   kubernetes.io/hostname=127.0.0.1   Ready     15d
centos7-1   kubernetes.io/hostname=centos7-1   Ready     4m
centos7-2   kubernetes.io/hostname=centos7-2   Ready     4m
[root@CentOS7 yum.repos.d]# kubectl cluster-info
Kubernetes master is running at http://localhost:8080