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="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
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
fi
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=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=""
3.3.2 /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（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=http://k8s-master:8080"
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=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(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 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 #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="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=""
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
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