Kubernetes集群部署

架构说明

centos7.4安装配置使用简介Kubernetes (k8s)
Kubernetes集群组件:

  • etcd 一个高可用的K/V键值对存储和服务发现系统
  • flannel 实现夸主机的容器网络的通信
  • kube-apiserver 提供kubernetes集群的API调用
  • kube-controller-manager 确保集群服务
  • kube-scheduler 调度容器,分配到Node
  • kubelet 在Node节点上按照配置文件中定义的容器规格启动容器
  • kube-proxy 提供网络代理服务
节点 IP地址
master 10.10.10.14
node1 10.10.10.15
node2 10.10.10.16

更改Hostname为 master、node1、node2,配置所有测试机的/etc/hosts文件

[root@master ~]# cat /etc/hosts
10.10.10.14 master  etcd  node14
10.10.10.15 node1   node15
10.10.10.16 node2   node16

关闭CentOS7自带的防火墙服务

安装

系统初始化安装(所有主机)-选择【最小化安装】,然后yum update,升级到最新版本
yum -y install epel-release
yum update

[root@master ~]#

yum install -y etcd kubernetes-master ntp flannel

[root@node1 ~]#

yum install -y kubernetes-node ntp flannel docker

时间校对
所有主机

systemctl start ntpd;systemctl enable ntpd
ntpdate ntp1.aliyun.com
hwclock -w

配置etcd服务器

[root@master ~]# grep -v '^#' /etc/etcd/etcd.conf

ETCD_NAME=default
ETCD_DATA_DIR="/var/lib/etcd/default.etcd"
ETCD_LISTEN_CLIENT_URLS="http://localhost:2379,http://10.10.10.14:2379"
ETCD_ADVERTISE_CLIENT_URLS="http://10.10.10.14:2379"

启动服务

systemctl start etcd;systemctl enable etcd

检查etcd cluster状态

[root@master ~]# etcdctl cluster-health   
member 8e9e05c52164694d is healthy: got healthy result from http://10.10.10.14:2379
cluster is healthy

检查etcd集群成员列表,这里只有一台

[root@master ~]# etcdctl member list
8e9e05c52164694d: name=default peerURLs=http://localhost:2380 clientURLs=http://10.10.10.14:2379 isLeader=true

配置master服务器

1) 配置kube-apiserver配置文件

[root@master ~]# grep -v '^#' /etc/kubernetes/config

KUBE_LOGTOSTDERR="--logtostderr=true"
KUBE_LOG_LEVEL="--v=0"
KUBE_ALLOW_PRIV="--allow-privileged=false"
KUBE_MASTER="--master=http://10.10.10.14:8080"

[root@master ~]# grep -v '^#' /etc/kubernetes/apiserver

KUBE_API_ADDRESS="--insecure-bind-address=0.0.0.0"
KUBE_ETCD_SERVERS="--etcd-servers=http://10.10.10.14:2379"
KUBE_SERVICE_ADDRESSES="--service-cluster-ip-range=10.254.0.0/16"
KUBE_ADMISSION_CONTROL="--admission-control=AlwaysAdmit"
KUBE_API_ARGS=""

2) 配置kube-controller-manager配置文件

[root@master ~]# grep -v '^#' /etc/kubernetes/controller-manager

KUBE_CONTROLLER_MANAGER_ARGS=""

3) 配置kube-scheduler配置文件

[root@master ~]# grep -v '^#' /etc/kubernetes/scheduler

KUBE_SCHEDULER_ARGS="--address=0.0.0.0"

4) 启动服务

for i in  kube-apiserver kube-controller-manager kube-scheduler;do systemctl restart $i; systemctl enable $i;done

配置node1节点服务器

1) 配置etcd

[root@master ~]# etcdctl set /atomic.io/network/config '{"Network": "172.16.0.0/16"}'
{"Network": "172.16.0.0/16"}

2) 配置node1网络,本实例采用flannel方式来配置,如需其他方式,请参考Kubernetes官网。

[root@node1 ~]# grep -v '^#' /etc/sysconfig/flanneld 
FLANNEL_ETCD_ENDPOINTS="http://10.10.10.14:2379"
FLANNEL_ETCD_PREFIX="/atomic.io/network"
FLANNEL_OPTIONS=""        

查看验证网络信息

[root@master ~]# etcdctl get /atomic.io/network/config  
{ "Network": "172.16.0.0/16" }
[root@master ~]# etcdctl ls /atomic.io/network/subnets
/atomic.io/network/subnets/172.16.69.0-24
/atomic.io/network/subnets/172.16.6.0-24
[root@master ~]# etcdctl get /atomic.io/network/subnets/172.16.6.0-24
{"PublicIP":"10.10.10.15"}
[root@master ~]# etcdctl get  /atomic.io/network/subnets/172.16.69.0-24
{"PublicIP":"10.10.10.16"}

3) 配置node1 kube-proxy

[root@node1 ~]# grep -v '^#' /etc/kubernetes/config 
KUBE_LOGTOSTDERR="--logtostderr=true"
KUBE_LOG_LEVEL="--v=0"
KUBE_ALLOW_PRIV="--allow-privileged=false"
KUBE_MASTER="--master=http://10.10.10.14:8080"
[root@node1 ~]# grep -v '^#' /etc/kubernetes/proxy                  
KUBE_PROXY_ARGS="--bind=address=0.0.0.0"
[root@node1 ~]# 

4) 配置node1 kubelet

[root@node1 ~]# grep -v '^#' /etc/kubernetes/kubelet 
KUBELET_ADDRESS="--address=127.0.0.1"
KUBELET_HOSTNAME="--hostname-override=10.10.10.15"
KUBELET_API_SERVER="--api-servers=http://10.10.10.14:8080"
KUBELET_POD_INFRA_CONTAINER="--pod-infra-container-image=registry.access.redhat.com/rhel7/pod-infrastructure:latest"
KUBELET_ARGS=""

5) 启动node1服务

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

配置node2节点服务器

node2与node1配置基本一致,除下面一处例外

[root@node2 ~]# vi /etc/kubernetes/kubelet
KUBELET_HOSTNAME="--hostname-override=10.10.10.16"

查看节点

[root@master ~]# kubectl get nodes   
NAME          STATUS    AGE
10.10.10.15   Ready     18h
10.10.10.16   Ready     13h

k8s支持2种方式,一种是直接通过命令参数的方式,另一种是通过配置文件的方式,配置文件的话支持json和yaml

命令方式

建立pod

kubectl run nginx --image=nginx --port=80  --replicas=2

遇到问题

创建成功但是kubectl get pods 没有结果
提示信息:no API token found for service account default
解决办法:编辑/etc/kubernetes/apiserver 去除 KUBE_ADMISSION_CONTROL中的SecurityContextDeny,ServiceAccount,并重启kube-apiserver.service服务

pod-infrastructure:latest镜像下载失败
报错信息:image pull failed for registry.access.redhat.com/rhel7/pod-infrastructure:latest, this may be because there are no credentials on this request.
解决方案:yum install *rhsm* -y

登陆容器报错
[root@node14 ~]# kubectl exec -it nginx-bl7lc /bin/bash
Error from server: error dialing backend: dial tcp 10.10.10.16:10250: getsockopt: connection refused
解决方法:
10250是kubelet的端口。
在Node上检查/etc/kubernetes/kubelet
KUBELET_ADDRESS需要修改为node ip

命令查看

[root@master log]# kubectl get pods
NAME                     READY     STATUS    RESTARTS   AGE
nginx-3449338310-h6l9d   1/1       Running   0          6m
nginx-3449338310-n4grl   1/1       Running   0          6m

[root@master log]# kubectl get deployment
NAME      DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
nginx          2          2         2       2       13m

通过端口将应用连接到公网

[root@node14 log]# kubectl expose deployment nginx --port=80 --type=LoadBalancer
service "nginx" exposed

expose命令将会创建一个service,将本地(某个节点上)的一个随机端口关联到容器中的80端口。
可以使用以下命令来查service:

[root@node14 log]# kubectl get service
NAME         CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE
kubernetes   10.254.0.1       <none>        443/TCP        21h
nginx        10.254.160.227   <pending>     80:30255/TCP   7s

外网访问:

[root@node16 ~]# elinks --dump http://10.10.10.16:30255
                           Welcome to nginx!

删除deployment 与service

[root@node14 log]# kubectl delete deployment nginx
deployment "nginx" deleted
[root@node14 log]# kubectl delete service nginx
service "nginx" deleted

配置文件方式

定义pod 文件

[root@node14 ~]# vim nginx-pod.yaml

apiVersion: v1
kind: Pod
metadata:
  name: nginx
  labels:
     app: nginx
spec:
     containers:
     - name: nginx
       image: nginx
       imagePullPolicy: IfNotPresent
       ports:
       - containerPort: 80
     restartPolicy: Always

发布到kubernetes集群中

[root@node14 ~]# kubectl create -f nginx-pod.yaml 
pod "nginx" created

查看pod

[root@node14 ~]# kubectl get pods
NAME      READY     STATUS    RESTARTS   AGE
nginx     1/1       Running   0          16s

定义与之关联的service 文件

[root@node14 ~]# vim nginx-svc.yaml

apiVersion: v1
kind: Service
metadata:
  name: nginx-service
spec:
  type: NodePort
  sessionAffinity: ClientIP
  selector:
    app: nginx
  ports:
    - port: 80
      nodePort: 30080

创建service

[root@node14 ~]# kubectl create -f nginx-svc.yaml 
service "nginx-service" created

查看刚刚创建的service

[root@node14 ~]# kubectl get service

NAME            CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE
kubernetes      10.254.0.1       <none>        443/TCP        23h
nginx-service   10.254.154.111   <nodes>       80:30080/TCP   20s

验证结果如下

[root@node16 log]# elinks --dump http://10.10.10.16:30080
                               Welcome to nginx!