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 kubernetes2.master节点需要安装etcd数据库服务，etcd作为kubernetes的数据库
yum -y install etcd3.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 $SERVICES
done
;;
*)
echo "useage:./k8s.sh <-s|-k|-stat>---- '-s' is start Servers\n--- '-k' is stop Servers\n'-stat' is watch the status "
;;
esac
8.node节点查看是否成功注册到master节点，如果没关闭防火墙会报错
tail -f /var/log/messages |grep kube9.master节点查看刚才注册的节点，节点status为ready为正常
kubectl get nodes10.kubectl是master端的交互工具，可以通过子命令查看节点等信息
kubectl get nodes #获取节点列表
kubectl cluster-info #查看节点信息下一节演示一个简单的kubernetes实例，master节点通过yaml文件，让node节点自动pull镜像并运行。**
如果启动docker报错，如下
当前docker版本1.13.1 执行启动命令： systemctl start docker ,报下面错误：
Error starting daemon: SELinux is not supported with the overlay2 graph driver on this kernel. Either boot into a newer kernel or disable selinux in docker (--selinux-enabled=false)
重新编辑docker配置文件：
vi /etc/sysconfig/docker
# /etc/sysconfig/docker
# Modify these options if you want to change the way the docker daemon runs
OPTIONS='--selinux-enabled=false --log-driver=journald --signature-verification=false'
if [ -z "${DOCKER_CERT_PATH}" ]; then
DOCKER_CERT_PATH=/etc/docker
fi
:wq
systemctl restart docker
