kubernetes集群搭建

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发布时间：2019-06-28

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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

集群搭建：

环境：三台宿主机：10.18.42.41 10.18.42.51 10.18.42.61

方便辨别改下主机名：

设置三台机器的主机名：

Master 10.18.42.41上执行：

hostnamectl --static set-hostname k8s-master　　

Node1 10.18.42.51上执行：

hostnamectl --static set-hostname k8s-node-1　　

Node2 10.18.42.61 上执行：

hostnamectl --static set-hostname k8s-node-2

三台互相解析：cat /etc/hosts：

10.18.42.41 k8s-master

10.18.42.41 etcd

10.18.42.41 registry

10.18.42.51 k8s-node-1

10.18.42.61 k8s-node-2

所有机器安装epel-release源,本身有就不用装了

yum -y install epel-release

2、部署etcd

　　k8s运行依赖etcd，需要先部署etcd，本文采用yum方式安装：

[root@localhost ~]# yum install etcd -y

yum安装的etcd默认配置文件在/etc/etcd/etcd.conf。编辑配置文件，更改以下带颜色部分信息：

[root@localhost ~]# vi /etc/etcd/etcd.conf

[member]

ETCD_NAME=master

ETCD_DATA_DIR="/var/lib/etcd/default.etcd"

#ETCD_WAL_DIR=""

#ETCD_SNAPSHOT_COUNT="10000"

#ETCD_HEARTBEAT_INTERVAL="100"

#ETCD_ELECTION_TIMEOUT="1000"

#ETCD_LISTEN_PEER_URLS=""

ETCD_LISTEN_CLIENT_URLS=""

#ETCD_MAX_SNAPSHOTS="5"

#ETCD_MAX_WALS="5"

#ETCD_CORS=""

#[cluster]

#ETCD_INITIAL_ADVERTISE_PEER_URLS=""

if you use different ETCD_NAME (e.g. test), set ETCD_INITIAL_CLUSTER value for this name, i.e. "test=http://..."

#ETCD_INITIAL_CLUSTER="default="

#ETCD_INITIAL_CLUSTER_STATE="new"

#ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"

ETCD_ADVERTISE_CLIENT_URLS=""

#ETCD_DISCOVERY=""

#ETCD_DISCOVERY_SRV=""

#ETCD_DISCOVERY_FALLBACK="proxy"

#ETCD_DISCOVERY_PROXY=""

启动并验证状态

[root@localhost ~]# systemctl start etcd

[root@localhost ~]# etcdctl set testdir/testkey0 0

[root@localhost ~]# etcdctl get testdir/testkey0

[root@localhost ~]# etcdctl -C cluster-health

member 8e9e05c52164694d is healthy: got healthy result from

cluster is healthy

[root@localhost ~]# etcdctl -C cluster-health

member 8e9e05c52164694d is healthy: got healthy result from

cluster is healthy

扩展：Etcd集群部署参见——

3、部署master

3.1 安装Docker

[root@k8s-master ~]# yum install docker

配置Docker配置文件，使其允许从registry中拉取镜像。

[root@k8s-master ~]# vim /etc/sysconfig/docker

/etc/sysconfig/docker

Modify these options if you want to change the way the docker daemon runs

OPTIONS='--selinux-enabled --log-driver=journald --signature-verification=false'

if [ -z "${DOCKER_CERT_PATH}" ]; then

DOCKER_CERT_PATH=/etc/docker

OPTIONS='--insecure-registry registry:5000'

设置开机自启动并开启服务

[root@k8s-master ~]# systemctl start docker

[root@k8s-master ~]# systemctl enable docker

3.2 安装kubernets

[root@k8s-master ~]# yum -y install kubernetes

3.3 配置并启动kubernetes

在kubernetes master上需要运行以下组件：

　　　　Kubernets API Server

　　　　Kubernets Controller Manager

　　　　Kubernets Scheduler

相应的要更改以下几个配置中带颜色部分信息：

3.3.1 /etc/kubernetes/apiserver

[root@k8s-master ~]# vim /etc/kubernetes/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="

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,ServiceAccount,ResourceQuota"

KUBE_ADMISSION_CONTROL="--admission-control=NamespaceLifecycle,NamespaceExists,LimitRanger,SecurityContextDeny,ResourceQuota"

Add your own!

KUBE_API_ARGS=""

3.3.2 /etc/kubernetes/config

[root@k8s-master ~]# vim /etc/kubernetes/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="

启动服务并设置开机自启动（先重启os）可以放在一个脚本文件里直接运行比如放在a文件

[root@k8s-master ~]# systemctl enable kube-apiserver.service

[root@k8s-master ~]# systemctl start kube-apiserver.service

[root@k8s-master ~]# systemctl enable kube-controller-manager.service

[root@k8s-master ~]# systemctl start kube-controller-manager.service

[root@k8s-master ~]# systemctl enable kube-scheduler.service

[root@k8s-master ~]# systemctl start kube-scheduler.service

re -check 采用netstat -ntlp或者loof -i:8080查看端口是否启用

4、部署node

4.1 安装docker yum -y install docker

　　参见3.1

4.2 安装kuberneets yum -y install kubernetes

　　参见3.2

4.3 配置并启动kubernetes

　　在kubernetes node上需要运行以下组件：

　　　　Kubelet

　　　　Kubernets Proxy

相应的要更改以下几个配置文中带颜色部分信息：

有几个node就copy以下配置

4.3.1 /etc/kubernetes/config

[root@K8s-node-1 ~]# vim /etc/kubernetes/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="

4.3.2 /etc/kubernetes/kubelet

[root@K8s-node-1 ~]# vim /etc/kubernetes/kubelet

###

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=k8s-node-1"

location of the api-server

KUBELET_API_SERVER="--api-servers="

pod infrastructure container

KUBELET_POD_INFRA_CONTAINER="--pod-infra-container-image=registry.access.redhat.com/rhel7/pod-infrastructure:latest"

Add your own!

KUBELET_ARGS=""

启动服务并设置开机自启动(注意是node1和node2上执行)

[root@k8s-master ~]# systemctl enable kubelet.service

[root@k8s-master ~]# systemctl start kubelet.service

[root@k8s-master ~]# systemctl enable kube-proxy.service

[root@k8s-master ~]# systemctl start kube-proxy.service

re -check 采用netstat -ntlp或者lsof -i:8080查看端口是否启用

4.4 查看状态

　　在master上查看集群中节点及节点状态（如果以上没端口没启用执行以下命令就会报 The connection to the server k8s-master:8080 was refused - did you specify the right host or port? ）

[root@k8s-master ~]# kubectl -s get node

NAME STATUS AGE

k8s-node-1 Ready 3m

k8s-node-2 Ready 16s

[root@k8s-master ~]# kubectl get nodes #获取集群状态

NAME STATUS AGE

k8s-node-1 Ready 3m

k8s-node-2 Ready 43s

至此，已经搭建了一个kubernetes集群，但目前该集群还不能很好的工作，请继续后续的步骤。

5、创建覆盖网络——Flannel

5.1 安装Flannel 三台节点都做

　　在master、node上均执行如下命令，进行安装

[root@k8s-master ~]# yum -y install flannel

版本为0.0.5

5.2 配置Flannel

　　master、node上均编辑/etc/sysconfig/flanneld，修改红色部分

[root@k8s-master ~]# vim /etc/sysconfig/flanneld

Flanneld configuration options

etcd url location. Point this to the server where etcd runs

FLANNEL_ETCD_ENDPOINTS=""

etcd config key. This is the configuration key that flannel queries

For address range assignment

FLANNEL_ETCD_PREFIX="/atomic.io/network"

Any additional options that you want to pass

#FLANNEL_OPTIONS=""

5.3 配置etcd中关于flannel的key

　　Flannel使用Etcd进行配置，来保证多个Flannel实例之间的配置一致性，所以需要在etcd上进行如下配置：（‘/atomic.io/network/config’这个key与上文/etc/sysconfig/flannel中的配置项FLANNEL_ETCD_PREFIX是相对应的，错误的话启动就会出错）

[root@k8s-master ~]# etcdctl mk /atomic.io/network/config '{ "Network": "10.0.0.0/16" }'

{ "Network": "10.0.0.0/16" }

结果： ip a 查看flannel已经添加成功

10.18.42.41：以后给这台服务器分发pod的IP就是方框内的网段的

5.4 启动

　　启动Flannel之后，需要依次重启docker、kubernete。

　　在master执行：

systemctl enable flanneld.service

systemctl start flanneld.service

service docker restart

systemctl restart kube-apiserver.service

systemctl restart kube-controller-manager.service