Centos7部署Kubernetes集群

一、环境介绍及准备：

1、物理机操作系统

物理机操作系统采用Centos7.3 64位，细节如下。

[root@localhost ~]# uname -a
Linux localhost.localdomain 3.10.0-514.6.1.el7.x86_64 #1 SMP Wed Jan 18 13:06:36 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
[root@localhost ~]# cat /etc/redhat-release 
CentOS Linux release 7.3.1611 (Core)

2、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：

设置三台机器的主机名：

Master上执行：

[root@localhost ~]#  hostnamectl --static set-hostname  k8s-master

Node1上执行：

[root@localhost ~]# hostnamectl --static set-hostname  k8s-node-1

Node2上执行：

[root@localhost ~]# hostnamectl --static set-hostname  k8s-node-2

在三台机器上设置hosts，均执行如下命令：

echo '10.0.251.148    k8s-master
10.0.251.148   etcd
10.0.251.148   registry
10.0.251.153   k8s-node-1
10.0.251.155    k8s-node-2' >> /etc/hosts

3、关闭三台机器上的防火墙

systemctl disable firewalld.service
systemctl stop firewalld.service

二、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="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

[root@localhost ~]# systemctl start etcd
[root@localhost ~]#  etcdctl set testdir/testkey0 0
0
[root@localhost ~]#  etcdctl get testdir/testkey0 
0
[root@localhost ~]# etcdctl -C http://etcd:4001 cluster-health
member 8e9e05c52164694d is healthy: got healthy result from http://0.0.0.0:2379
cluster is healthy
[root@localhost ~]# etcdctl -C http://etcd:2379 cluster-health
member 8e9e05c52164694d is healthy: got healthy result from http://0.0.0.0:2379
cluster is healthy

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

三、部署master

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
if [ -z "${DOCKER_CERT_PATH}" ]; then
    DOCKER_CERT_PATH=/etc/docker
fi

设置开机自启动并开启服务

[root@k8s-master ~]# chkconfig docker on
[root@k8s-master ~]# service docker start

2、安装kubernets

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

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：

3.1 /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=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=""

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=http://k8s-master:8080"

启动服务并设置开机自启动

[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

四、部署node

1、安装docker

参见3.1

2、安装kubernets

参见3.2

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：

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=http://k8s-master:8080"

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=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=""

启动服务并设置开机自启动

[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

4、查看状态

在master上查看集群中节点及节点状态

[root@k8s-master ~]#  kubectl -s http://k8s-master:8080 get node
NAME         STATUS    AGE
k8s-node-1   Ready     3m
k8s-node-2   Ready     16s
[root@k8s-master ~]# 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。

五、创建覆盖网络——Flannel

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

版本为0.0.5

2、配置Flannel

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

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

# 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=""

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" }

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