centos7.4安装配置使用简介Kubernetes (k8s)

it2024-10-19 12

Kubernetes集群部署

来源：https://blog.51cto.com/2168836/2106963?utm_source=oschina-app

架构说明

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Nodekubelet 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master10.10.10.14node110.10.10.15node210.10.10.16

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!

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