centos7.4安装配置使用简介Kubernetes (k8s)

╰+攻爆jí腚メ 2021-11-11 00:56 187阅读 0赞

# Kubernetes集群部署 #

来源：[https://blog.51cto.com/2168836/2106963?utm\_source=oschina-app][https_blog.51cto.com_2168836_2106963_utm_source_oschina-app]

## 架构说明 ##

![centos7.4安装配置使用简介Kubernetes (k8s)][centos7.4_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

<table> 
 <thead> 
  <tr> 
   <th>节点</th> 
   <th>IP地址</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>master</td> 
   <td>10.10.10.14</td> 
  </tr> 
  <tr> 
   <td>node1</td> 
   <td>10.10.10.15</td> 
  </tr> 
  <tr> 
   <td>node2</td> 
   <td>10.10.10.16</td> 
  </tr> 
 </tbody> 
</table>

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!

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![20190803230526516.jpeg][]

[https_blog.51cto.com_2168836_2106963_utm_source_oschina-app]: https://blog.51cto.com/2168836/2106963?utm_source=oschina-app
[centos7.4_Kubernetes _k8s]: https://imgconvert.csdnimg.cn/aHR0cHM6Ly9zMS41MWN0by5jb20vaW1hZ2VzL2Jsb2cvMjAxODA0LzI0Lzc5MmEyNWZlMmQyMmI4NTRlY2E1NTMwNDhkOTE4OWI2LnBuZz94LW9zcy1wcm9jZXNzPWltYWdlL3dhdGVybWFyayxzaXplXzE2LHRleHRfUURVeFExUlA1WTJhNWE2aSxjb2xvcl9GRkZGRkYsdF8xMDAsZ19zZSx4XzEwLHlfMTAsc2hhZG93XzkwLHR5cGVfWm1GdVozcG9aVzVuYUdWcGRHaz0
[20190803230526516.jpeg]: https://img-blog.csdnimg.cn/20190803230526516.jpeg