Kubernates集群入门（1）

一、K8s安装准备

1.至少两台主机，一台作为master，一台作为node。两台主机需要关闭防火墙。

#centos6 
service stop firewalld  && service disable firewalld

#centos7
systemctl stop iptables && systemctl disable iptables;

2.两台机器需要各自编辑/etc/hosts文件，互相添加hostname，然后相互ping通，以下为例

echo "192.168.18.128 centos-master
192.168.18.130 centos-minion
" >> /etc/hosts

二、K8s的安装

1.两台主机都需要安装docker，kubernetes，如有docker版本冲突需要卸载重新安装docker.

yum -y install docker kubernetes

2.master节点需要安装etcd数据库服务，etcd作为kubernetes的数据库

yum -y install etcd

3.每个节点,master及minion节点都需要修改kubernetes配置文件

vim /etc/kubernetes/config

# How the controller-manager, scheduler, and proxy find the apiserver
KUBE_MASTER="--master=http://centos-master:8080"
#master节点关于指向etcd的ip可能需要改成127.0.0.1:2379，改成主机名的话kube-controller-manager可能会启动失败，不知原因
KUBE_ETCD_SERVERS="--etcd_servers=http://centos-master:2379"

示例master 下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 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=false"

# How the controller-manager, scheduler, and proxy find the apiserver
KUBE_MASTER="--master=http://kube01:8080"

KUBE_ETCD_SERVERS="--etcd-servers=http://kube01:2379"

4.master节点上，配置api服务给node

vim /etc/kubernetes/apiserver

# The address on the local server to listen to.
#这个地址好像只能用0.0.0.0
KUBE_API_ADDRESS="--address=0.0.0.0"
KUBE_API_PORT="--port=8080"
# Comma separated list of nodes in the etcd cluster
#KUBE_ETCD_SERVERS="--etcd_servers=http://127.0.0.1:2379"

##ServiceAccount这个参数删掉，会影响docker拉去镜像
# default admission control policies
KUBE_ADMISSION_CONTROL="--admission-control=NamespaceLifecycle,NamespaceExists,LimitRanger,SecurityContextDeny,ServiceAccount,ResourceQuota"

示例：master节点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="--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=http://127.0.0.1:2379"

# 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=NamespaceLifecycle,NamespaceExists,LimitRanger,SecurityContextDeny,ResourceQuota"

# Add your own!
KUBE_API_ARGS=""

5.master节点上编写启动相关kubernetes服务的脚本

vim k8s-server.sh

#!/bin/bash

OPT=$1

case $1 in
-s)
 for SERVICES in etcd  kube-apiserver kube-controller-manager kube-scheduler; do
        systemctl restart $SERVICES
        systemctl enable $SERVICES
        systemctl status $SERVICES
 done
;;

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

-stat)
 for SERVICES in etcd  kube-apiserver kube-controller-manager kube-scheduler; do
        systemctl status $SERVICES
done
;;
*)
        echo "useage:./k8s-server.sh <-s|-k|-stat>----  '-s' is start Servers\n---  '-k' is stop Servers\n'-stat' is watch the status  "
;;
esac

6.node节点修改/etc/kubernetes/kubelet，配置与master的连接

###
# kubernetes kubelet (minion) config
KUBELET_ADDRESS="--address=0.0.0.0"
KUBELET_PORT="--port=10250"
KUBELET_HOSTNAME="--hostname_override=centos-minion"
KUBELET_API_SERVER="--api_servers=http://centos-master:8080“
# Add your own!
KUBELET_ARGS=""

minion节点 config示例

###
# 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=false"

# How the controller-manager, scheduler, and proxy find the apiserver
KUBE_MASTER="--master=http://kube01:8080"

minion节点kubelet示例

###
# 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 on
#KUBELET_PORT="--port=10250"

# You may leave this blank to use the actual hostname
KUBELET_HOSTNAME="--hostname-override=kube02"

# location of the api-server
KUBELET_API_SERVER="--api-servers=http://kube01:8080"

# pod infrastructure container
KUBELET_POD_INFRA_CONTAINER="--pod-infra-container-image=registry.access.redhat.com/rhel7/pod-infrastructure:latest"

# Add your own!
KUBELET_ARGS=""

7.node节点编写启动和查看服务脚本

#!/bin/bash

OPT=$1

case $1 in
-s)
 for SERVICES in kube-proxy kubelet docker; do
        systemctl restart $SERVICES
        systemctl enable $SERVICES
        systemctl status $SERVICES
 done
;;

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

-stat)
 for SERVICES in kube-proxy kubelet docker; do
        systemctl status $SERVICES
done
;;
*)
        echo "useage:./k8s.sh <-s|-k|-stat>----  '-s' is start Servers\n---  '-k' is stop Servers\n'-stat' is watch the status  "
;;
esac

8.node节点查看是否成功注册到master节点，如果没关闭防火墙会报错

tail -f /var/log/messages |grep kube

9.master节点查看刚才注册的节点，节点status为ready为正常

kubectl get nodes

10.kubectl是master端的交互工具，可以通过子命令查看节点等信息

kubectl get nodes #获取节点列表

kubectl cluster-info #查看节点信息

下一节演示一个简单的kubernetes实例，master节点通过yaml文件，让node节点自动pull镜像并运行。**

如果启动docker报错，如下

当前docker版本1.13.1 执行启动命令： systemctl   start docker  ,报下面错误：

Error starting daemon: SELinux is not supported with the overlay2 graph driver on this kernel. Either boot into a newer kernel or disable selinux in docker (--selinux-enabled=false)

重新编辑docker配置文件：
vi /etc/sysconfig/docker
# /etc/sysconfig/docker

# Modify these options if you want to change the way the docker daemon runs

OPTIONS='--selinux-enabled=false  --log-driver=journald --signature-verification=false'
if [ -z "${DOCKER_CERT_PATH}" ]; then
    DOCKER_CERT_PATH=/etc/docker
fi

:wq 



systemctl  restart  docker