Kubernetes集羣組件:
- etcd 一個高可用的K/V鍵值對存儲和服務發現系統
- flannel 實現誇主機的容器網絡的通信
- kube-apiserver 提供kubernetes集羣的API調用
- kube-controller-manager 確保集羣服務
- kube-scheduler 調度容器，分配到Node
- kubelet 在Node節點上按照配置文件中定義的容器規格啓動容器
- kube-proxy 提供網絡代理服務
集羣搭建：
環境：三臺宿主機：10.18.42.41 10.18.42.51 10.18.42.61
方便辨別改下主機名：
設置三臺機器的主機名：
Master 10.18.42.41上執行：
hostnamectl --static set-hostname k8s-master
Node1 10.18.42.51上執行：
hostnamectl --static set-hostname k8s-node-1
Node2 10.18.42.61 上執行：
hostnamectl --static set-hostname k8s-node-2
三臺互相解析：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
所有機器安裝epel-release源,本身有就不用裝了
yum -y install epel-release
2、部署etcd
k8s運行依賴etcd，需要先部署etcd，本文采用yum方式安裝：
[root@localhost ~]# yum install etcd -y
yum安裝的etcd默認配置文件在/etc/etcd/etcd.conf。編輯配置文件，更改以下帶顏色部分信息：
[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=""
啓動並驗證狀態
[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
擴展：Etcd集羣部署參見——http://www.cnblogs.com/zhenyuyaodidiao/p/6237019.html
3、部署master
3.1 安裝Docker
[root@k8s-master ~]# yum install docker
配置Docker配置文件，使其允許從registry中拉取鏡像。
[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'
設置開機自啓動並開啓服務
[root@k8s-master ~]# systemctl start docker
[root@k8s-master ~]# systemctl enable docker
3.2 安裝kubernets
[root@k8s-master ~]# yum -y install kubernetes
3.3 配置並啓動kubernetes
在kubernetes master上需要運行以下組件：
Kubernets API Server
Kubernets Controller Manager
Kubernets Scheduler
相應的要更改以下幾個配置中帶顏色部分信息：
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"
啓動服務並設置開機自啓動（先重啓os） 可以放在一個腳本文件裏直接運行 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 採用netstat -ntlp或者loof -i:8080查看端口是否啓用
4、部署node
4.1 安裝docker yum -y install docker
參見3.1
4.2 安裝kuberneets yum -y install kubernetes
參見3.2
4.3 配置並啓動kubernetes
在kubernetes node上需要運行以下組件：
Kubelet
Kubernets Proxy
相應的要更改以下幾個配置文中帶顏色部分信息：
有幾個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=""
啓動服務並設置開機自啓動(注意是node1和node2上執行)
[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 採用netstat -ntlp或者lsof -i:8080查看端口是否啓用
4.4 查看狀態
在master上查看集羣中節點及節點狀態（如果以上沒端口沒啓用執行以下命令就會報 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 #獲取集羣狀態
NAME STATUS AGE
k8s-node-1 Ready 3m
k8s-node-2 Ready 43s
至此，已經搭建了一個kubernetes集羣，但目前該集羣還不能很好的工作，請繼續後續的步驟。
5、創建覆蓋網絡——Flannel
5.1 安裝Flannel 三臺節點都做
在master、node上均執行如下命令，進行安裝
[root@k8s-master ~]# yum -y install flannel
版本爲0.0.5
5.2 配置Flannel
master、node上均編輯/etc/sysconfig/flanneld，修改紅色部分
[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中關於flannel的key
Flannel使用Etcd進行配置，來保證多個Flannel實例之間的配置一致性，所以需要在etcd上進行如下配置：（‘/atomic.io/network/config’這個key與上文/etc/sysconfig/flannel中的配置項FLANNEL_ETCD_PREFIX是相對應的，錯誤的話啓動就會出錯）
[root@k8s-master ~]# etcdctl mk /atomic.io/network/config '{ "Network": "10.0.0.0/16" }'
{ "Network": "10.0.0.0/16" }
結果： ip a 查看flannel已經添加成功
10.18.42.41：以後給這臺服務器分發pod的IP就是方框內的網段的
5.4 啓動
啓動Flannel之後，需要依次重啓docker、kubernete。
在master執行：
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上執行：
systemctl enable flanneld.service
systemctl start flanneld.service
service docker restart
systemctl restart kubelet.service
systemctl restart kube-proxy.service