CentOS7搭建k8s集群

一.机器信息

[root@kube-gmg-03-master-1 ~]# uname -a
Linux kube-gmg-03-master-1 3.10.0-957.el7.x86_64 #1 SMP Thu Nov 8 23:39:32 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
[root@kube-gmg-03-master-1 ~]# cat /etc/redhat-release
CentOS Linux release 7.9.2009 (Core)

二、主机信息

本文准备了三台机器用于部署k8s的运行环境，细节如下：

节点及功能	主机名	IP
Master、etcd、registry	K8s-master	10.255.61.1
Node1	K8s-node-1	10.255.61.2
Node2	K8s-node-2	10.255.61.3

三、设置三台机器的主机名

　　Master上执行：

hostnamectl --static set-hostname  k8s-master

　　Node1上执行：

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

　　Node2上执行：

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

四、设置hosts

三台机器均执行如下命令：

echo '10.255.61.1    k8s-master
10.255.61.1   etcd
10.255.61.1   registry
10.255.61.2   k8s-node-1
10.255.61.3    k8s-node-2' >> /etc/hosts

五、关闭三台机器上的防火墙

systemctl disable firewalld.service
systemctl stop firewalld.service

 六、三台机器部署etcd

  k8s运行依赖etcd，需要先部署etcd，本文采用yum方式安装：

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：

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="http://0.0.0.0:2380"
ETCD_LISTEN_CLIENT_URLS="http://0.0.0.0:2379,http://0.0.0.0:4001"
#ETCD_MAX_SNAPSHOTS="5"
#ETCD_MAX_WALS="5"
#ETCD_CORS=""
#
#[cluster]
#ETCD_INITIAL_ADVERTISE_PEER_URLS="http://localhost:2380"
# 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=http://localhost:2380"
#ETCD_INITIAL_CLUSTER_STATE="new"
#ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
ETCD_ADVERTISE_CLIENT_URLS="http://etcd:2379,http://etcd:4001"
#ETCD_DISCOVERY=""
#ETCD_DISCOVERY_SRV=""
#ETCD_DISCOVERY_FALLBACK="proxy"
#ETCD_DISCOVERY_PROXY="" 

启动并验证状态（先启动master的etcd）

扩展：Etcd集群部署参见——http://www.cnblogs.com/zhenyuyaodidiao/p/6237019.html

七、部署master

7.1 安装docker

yum install docker -y

配置Docker配置文件，使其允许从registry中拉取镜像。

vim /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
fi
OPTIONS='--insecure-registry registry:5000'

设置开机自启动并开启服务

systemctl enable docker.service
systemctl start docker

7.2 安装kubernets

yum install kubernetes -y

7.3 配置并启动kubernetes

在kubernetes master上需要安装运行以下组件：

Kubernets API Server
Kubernets Controller Manager
Kubernets Scheduler

7.4 相应的要更改以下几个配置中带颜色部分信息：

###
# 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=http://etcd: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,ServiceAccount,ResourceQuota"
KUBE_ADMISSION_CONTROL="--admission-control=NamespaceLifecycle,NamespaceExists,LimitRanger,SecurityContextDeny,ResourceQuota"

# Add your own!
KUBE_API_ARGS=""

###
# 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://k8s-master:8080"

7.5 启动服务并设置开机自启动，运行如下命令

 systemctl enable kube-apiserver.service
 systemctl start kube-apiserver.service
 systemctl enable kube-controller-manager.service
 systemctl start kube-controller-manager.service
 systemctl enable kube-scheduler.service
 systemctl start kube-scheduler.service

八、部署node节点

8.1 参考7.1安装docker 参考7.2安装kubernets

8.2 node节点启动kubernets

在kubernetes node上需要运行以下组件：

　　　　Kubelet

　　　　Kubernets Proxy

8.2.1 配置文件

###
# 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://k8s-master:8080"

###
# 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=http://k8s-master:8080"

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

# Add your own!
KUBELET_ARGS=""

8.3 启动服务并设置开机自启动

systemctl enable kubelet.service
systemctl start kubelet.service
systemctl enable kube-proxy.service
systemctl start kube-proxy.service

8.4 查看状态

　　在master上查看集群中节点及节点状态

NAME         STATUS    AGE
k8s-node-1   Ready     3m
k8s-node-2   Ready     16s
$ kubectl get nodes
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。

九、创建覆盖网络——Flannel

9.1 安装Flannel

　　在master、node上均执行如下命令，进行安装

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

9.2 配置Flannel

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

# Flanneld configuration options

# etcd url location.  Point this to the server where etcd runs
FLANNEL_ETCD_ENDPOINTS="http://etcd:2379"

# 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=""

9.3 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" }

9.4 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
systemctl restart kube-scheduler.service

　　在node上执行：

systemctl enable flanneld.service 
systemctl start flanneld.service 
service docker restart
systemctl restart kubelet.service
systemctl restart kube-proxy.service

涉及到的书籍——Kubernetes实战、Kubernetes权威指南：从Docker到Kubernetes实践全接触、每天5分钟玩转Docker容器技术 、Docker容器：利用Kubernetes、Flannel、Cockpit和Atomic构建和部署

感谢https://www.cnblogs.com/zhenyuyaodidiao/p/6500830.html

结束！