CentOS7下搭建Kubernetes集群

hwl198212

1、测试环境
　　操作系统：CentOS Linux release 7.4.1708

• 操作机        192.168.1.200
  
• kube-master   192.168.1.210
  
• kube-minion-1 192.168.1.211
  
• kube-minion-2 192.168.1.212
  
• kube-minion-3 192.168.1.213
  

2、准备工作

2.1 所有服务器设置静态IP
　　在 /etc/sysconfig/network-scripts 路径下找到 ifcfg- ， 代表具体网卡，本文修改的网卡是 ifcfg-enp0s3

ONBOOT=yes #开机启动
BOOTPROTO=static #静态IP
IPADDR=192.168.1.200 #本机地址
NETMASK=255.255.255.0 #子网掩码
GATEWAY=192.168.1.1 #默认网关
2.2 所有服务器设置DNS
　　配置文件/etc/sysconfig/network

# Created by anaconda
DNS1=192.168.1.1
DNS2=8.8.8.8
2.3 所有服务器修改hostname

hostnamectl --static set-hostname [主机名]
　　注：修改成与/etc/hosts对应的相同名称！

2.4 操作机向所有服务器添加公钥实现免密码登录
　　通过ssh-keygen -t rsa和ssh-copy-id命令，不再赘述

2.5 在操作机安装Ansible

yum install ansible
2.6 配置Ansible
　　编辑/etc/ansible/hosts,在末尾添加服务器信息，添加组：kube、master、nodes:

[kube]
192.168.1.[210:213]
[master]
192.168.1.210
[nodes]
192.168.1.[211:213]
2.7 测试Ansible
　　查询kube组内所有服务器启动运行时间：

ansible kube -a 'uptime'
2.8 所有服务器安装EPEL扩展源

ansible kube -m shell -a 'yum -y install epel-release'
2.9 所有服务器修改/etc/hosts

ansible kube -m shell -a 'echo -e "192.168.1.210    kube-master\n192.168.1.211    kube-minion-1\n192.168.1.212    kube-minion-2\n192.168.1.213    kube-minion-3" >> /etc/hosts'
　　注：如果不加参数-m shell，会默认使用command模块导致添加失败

2.10 查看所有主机的/etc/hosts

ansible kube -a 'cat /etc/hosts'
2.11 所有服务器安装Docker

ansible kube -m shell -a 'yum -y install docker'
或
ansible kube -m yum -a 'name=docker state=present'
2.12 查看所有服务器是否成功安装Docker

ansible kube -m yum -a 'name=docker state=present'
2.13 所有服务器设置Docker开机启动并启动服务

ansible kube -m service -a 'name=docker state=restarted enabled=yes'
2.14 检查所有服务器Docker服务是否正常启动

ansible kube -m shell -a 'systemctl status docker'
2.15 所有服务器安装时间同步工具NTP

ansible kube -m yum -a 'name=ntp state=present'
　　注：NTP配置文件在/etc/ntp.conf，可以对NTP服务器进行设置，NTP服务器可访问http://www.pool.ntp.org/zh/查看，pool.ntp.org是一个高可用时间服务器虚拟集群项目，网站建议使用下列默认域名，每个域名会每小时随机一组NTP服务器，进行时间同步时它会随机返回离你较近的NTP服务器。

server 0.pool.ntp.org
server 1.pool.ntp.org
server 2.pool.ntp.org
server 3.pool.ntp.org
2.16 所有服务器启动NTP服务并设开机启动

ansible kube -m service -a 'name=ntpd state=restarted enabled=yes'
2.17 查看所有服务器NTP服务是否正常开启

ansible kube -m shell -a 'systemctl status ntpd'
2.18 查看所有服务器获得到的NTP服务器列表

ansible kube -a 'ntpq -p'
　　注：NTP服务器列表可能需要等几分钟后才能获得并完成对时，每个服务器获得的NTP服务器不一样是正常的。

3、安装配置Kubernetes
　　以下步骤参考Kubernetes官网教程：  
https://kubernetes.io/docs/getting-started-guides/centos/centos_manual_config/

3.1 所有服务器配置YUM库源

ansible kube -m shell -a 'echo "[virt7-docker-common-release]
name=virt7-docker-common-release
baseurl=http://cbs.centos.org/repos/virt7-docker-common-release/x86_64/os/
gpgcheck=0" > /etc/yum.repos.d/virt7-docker-common-release.repo'
3.2 所有服务器安装Kubernetes,etcd,flannel

ansible kube -m shell -a 'yum -y install --enablerepo=virt7-docker-common-release kubernetes etcd flannel'
3.3 所有服务器修改/etc/kubernetes/config配置文件
　　默认内容：

###
# 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://127.0.0.1:8080"
　　需要把KUBE_MASTER改成:

KUBE_MASTER="--master=http://kube-master:8080"
　　操作机执行修改命令：

ansible kube -m shell -a 'echo  "###
# 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://kube-master:8080\"" > /etc/kubernetes/config'
3.4 所有服务器关掉SELinux和防火墙，并重启

ansible kube -m shell -a 'setenforce 0;
systemctl disable firewalld;
systemctl stop firewalld;
reboot'
3.5 kube-master修改etcd配置文件
　　配置文件在/etc/etcd/etcd.conf，注意确认配置文件中的以下参数与下文一致，主要是两个localhost改成0.0.0.0

# [member]
ETCD_NAME=default
ETCD_DATA_DIR="/var/lib/etcd/default.etcd"
ETCD_LISTEN_CLIENT_URLS="http://0.0.0.0:2379"
#[cluster]
ETCD_ADVERTISE_CLIENT_URLS="http://0.0.0.0:2379"
3.6 kube-master修改apiserver配置文件
　　打开/etc/kubernetes/apiserver，用以下内容覆盖：

# The address on the local server to listen to.
KUBE_API_ADDRESS="--address=0.0.0.0"
# The port on the local server to listen on.
KUBE_API_PORT="--port=8080"
# Port kubelets listen on
KUBELET_PORT="--kubelet-port=10250"
# Comma separated list of nodes in the etcd cluster
KUBE_ETCD_SERVERS="--etcd-servers=http://kube-master: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=""
　　注：KUBE_ADMISSION_CONTROL里去掉了ServiceAccount

3.7 kube-master上启动ETCD

systemctl start etcd
etcdctl mkdir /kube-centos/network
etcdctl mk /kube-centos/network/config "{ \"Network\": \"172.30.0.0/16\", \"SubnetLen\": 24, \"Backend\": { \"Type\": \"vxlan\" } }"
3.8 所有服务器上修改flannel配置
　　配置文件/etc/sysconfig/flanneld，修改成以下内容：

# Flanneld configuration options
# etcd url location.  Point this to the server where etcd runs
FLANNEL_ETCD_ENDPOINTS="http://kube-master:2379"
# etcd config key.  This is the configuration key that flannel queries
# For address range assignment
FLANNEL_ETCD_PREFIX="/kube-centos/network"
# Any additional options that you want to pass
#FLANNEL_OPTIONS=""
　　批量修改指令：

ansible kube -m shell -a 'echo "# Flanneld configuration options
# etcd url location.  Point this to the server where etcd runs
FLANNEL_ETCD_ENDPOINTS=\"http://kube-master:2379\"
# etcd config key.  This is the configuration key that flannel queries
# For address range assignment
FLANNEL_ETCD_PREFIX=\"/kube-centos/network\"
# Any additional options that you want to pass
#FLANNEL_OPTIONS=\"\"" > /etc/sysconfig/flanneld'
3.9 kube-master上启动服务

for SERVICES in etcd kube-apiserver kube-controller-manager kube-scheduler flanneld; do
systemctl restart $SERVICES
systemctl enable $SERVICES
systemctl status $SERVICES
done
3.10 所有nodes服务器配置kubelet
　　配置文件/etc/kubernetes/kubelet，改为以下内容：

# The address for the info server to serve on
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
# Check the node number!
KUBELET_HOSTNAME="--hostname-override=kube-minion-n"
# Location of the api-server
KUBELET_API_SERVER="--api-servers=http://kube-master:8080"
KUBELET_POD_INFRA_CONTAINER="--pod-infra-container-image=registry.access.redhat.com/rhel7/pod-infrastructure:latest"
# Add your own!
KUBELET_ARGS=""
　　注：这里注释掉了KUBELET_HOSTNAME，是为了使用服务器主机名当kubelet名  
批量操作指令：

ansible nodes -m shell -a 'echo "# The address for the info server to serve on
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
# Check the node number!
KUBELET_HOSTNAME=\"kube-minion-n\"
# Location of the api-server
KUBELET_API_SERVER=\"--api-servers=http://kube-master:8080\"
# Add your own!
KUBELET_ARGS=\"\"" >/etc/kubernetes/kubelet'
　　注：KUBELET_HOSTNAME要改成和/etc/hosts里的一致

3.11 所有nodes服务器启动服务

ansible nodes -m shell -a 'for SERVICES in kube-proxy kubelet flanneld docker; do
systemctl restart $SERVICES
systemctl enable $SERVICES
systemctl status $SERVICES
done'
3.12 kube-master上启动Kuberneters集群

kubectl config set-cluster default-cluster --server=http://kube-master:8080
kubectl config set-context default-context --cluster=default-cluster --user=default-admin
kubectl config use-context default-context
kubectl get nodes
3.13 大功告成！~
　　目前为止Kubernetes就搭建完了，拍拍自己肩膀说干的不错小伙~ :P

4、搭建Dashboard

4.1 获得Dashboard的Docker镜像
　　需要用到下列两个Docker镜像:

• gcr.io/google_containers/kubernetes-dashboard-amd64:v1.5.1
  
• registry.access.redhat.com/rhel7/pod-infrastructure:latest
  

　　由于国内被屏蔽无法直接下载到，所以要用可以访问的主机下载后添加到所有主机里。也可以通过docker tag命令添加到Docker私有库后使用。
　　操作指令:

# 导出镜像
docker save gcr.io/google_containers/kubernetes-dashboard-amd64:v1.5.1 > dashboard.tar
# 导入镜像
docker load < dashboard.tar
4.2 编辑Dashboard的YAML
　　编辑kubernetes-dashboard.yaml,内容如下：

kind: Deployment
apiVersion: extensions/v1beta1
metadata:
labels:
app: kubernetes-dashboard
name: kubernetes-dashboard
namespace: kube-system
spec:
replicas: 1
selector:
matchLabels:
app: kubernetes-dashboard
template:
metadata:
labels:
app: kubernetes-dashboard
# Comment the following annotation if Dashboard must not be deployed on master
annotations:
scheduler.alpha.kubernetes.io/tolerations: |
[
{
"key": "dedicated",
"operator": "Equal",
"value": "master",
"effect": "NoSchedule"
}
]
spec:
containers:
- name: kubernetes-dashboard
image: gcr.io/google_containers/kubernetes-dashboard-amd64:v1.5.1
imagePullPolicy: IfNotPresent
ports:
- containerPort: 9090
protocol: TCP
args:
# Uncomment the following line to manually specify Kubernetes API server Host
# If not specified, Dashboard will attempt to auto discover the API server and connect
# to it. Uncomment only if the default does not work.
- --apiserver-host=http://192.168.1.210:8080    #注意这里是master的api的地址，要写master的IP，写域名会报错提示访问不到
livenessProbe:
httpGet:
path: /
port: 9090
initialDelaySeconds: 30
timeoutSeconds: 30
---
kind: Service
apiVersion: v1
metadata:
labels:
app: kubernetes-dashboard
name: kubernetes-dashboard
namespace: kube-system
spec:
type: NodePort
ports:
- port: 80
targetPort: 9090
selector:
app: kubernetes-dashboard
4.2 部署Dashboard
　　在kube-master上运行：

#开启Dashboard
kubectl create -f kubernetes-dashboard.yaml
#查看pod运行状态
kubectl get pods --all-namespaces
#返回结果示例：
#NAMESPACE     NAME                                    READY     STATUS    #RESTARTS   AGE
#kube-system   kubernetes-dashboard-3345393181-6vq94   1/1       Running   0          44m
#kube-system   zl-redis-1545002913-89r4m               1/1       Running   0          38m
#kube-system   zl-redis-1545002913-cbgv5               1/1       Running   0          38m
#查看单个pod的描述
kubectl describe pod/[pod名字] --namespace=[命名空间]
#例：kubectl describe pod/zl-redis-1545002913-cbgv5 --namespace=kube-system
#查看pod日志
kubectl logs -f [pod名字] --namespace=[命名空间]
#例：kubectl logs -f zl-redis-1545002913-cbgv5 --namespace=kube-system

4.4 浏览器访问
　　访问kube-master网址：http://192.168.1.210:8080/ui