Kubernetes是谷歌开源的容器集群编排平台，是一个完备的分布式系统支撑平台，为容器化应用提供部署运行、资源调度、服务发现和动态伸缩等一系列完整功能，具有强大的故障发现和自我修复机制、服务滚动升级和在线扩容能力，可扩展资源自动调度机制以及多粒度的资源配额管理能力。
Kubernetes目前以77%的市场份额独占容器编排平台市场鳌头。目前所有的主要云服务提供商（亚马逊、微软、Google、IBM等）都将其作为部署云原生应用的解决方案。Kubernetes已经在大量企业中落地，并广泛的运用在生产环境中。
作为容器化的主流运行和编排管理平台，Kubernetes的重要性毋庸置疑，以下相关内容只是本人的相关笔记，仅作参考，欢迎业内各路大神指点。
下面是K8S架构简图：
可以看出，K8S架构分Master+Node两部分，其中Master节点作为管理节点，主要提供管理用户相关操作，Node节点作为应用部署节点，实现业务功能，被Master节点管理控制和调度。通过Master和Node节点的各大组件，不难看出，要安装K8S集群，需要分别安装如下组件：
Master节点：
| 组件名称 | 组件说明 |
| etcd | 非关系型数据库，用于存储相关信息 |
| kube-apiserver | 核心通信组件，其他组件通过它实现通信 |
| kube-controller-manager | 集群内部管理中心，通过各种manager实现集群管理 |
| kube-scheduler | 负责相关调度，比如node上pod的调度 |
Node节点：
| 组件名称 | 组件说明 |
| kube-proxy | 负责网络通信，相当与代理，实现请求到pod的转发 |
| kubelet | node节点核心组件，作为Master节点任务的执行者 |
安装环境如下：
| 操作系统 | 节点角色 | 节点IP |
| centOS7.2 X64 | Master | 120.27.15.116 |
| centOS7.2 X64 | node | 39.108.85.46 |
安装过程如下：
step1、安装etcd，这个不属于k8s的东东，直接通过yum install etcd 安装即可
[root@alta-sz kubernetes]# yum install etcd
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
Resolving Dependencies
--> Running transaction check
---> Package etcd.x86_64 :3.2.-.el7 will be installed
--> Finished Dependency Resolution Dependencies Resolved ========================================================================================================================================================================
Package Arch Version Repository Size
========================================================================================================================================================================
Installing:
etcd x86_64 3.2.-.el7 extras 9.3 M Transaction Summary
========================================================================================================================================================================
Install Package Total download size: 9.3 M
Installed size: M
Is this ok [y/d/N]: y
Downloading packages:
etcd-3.2.-.el7.x86_64.rpm | 9.3 MB ::
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
Installing : etcd-3.2.-.el7.x86_64 /
Verifying : etcd-3.2.-.el7.x86_64 / Installed:
etcd.x86_64 :3.2.-.el7 Complete!
安装完进行配置：
vi /etc/etcd/etcd.conf
[root@alta-sz etcd]# vi /etc/etcd/etcd.conf #[Member]
#ETCD_CORS=""
ETCD_DATA_DIR="/var/lib/etcd/default.etcd"
#ETCD_WAL_DIR=""
#ETCD_LISTEN_PEER_URLS="http://localhost:2380"
ETCD_LISTEN_CLIENT_URLS="http://0.0.0.0:2379,http://0.0.0.0:4001"
#ETCD_MAX_SNAPSHOTS=""
#ETCD_MAX_WALS=""
ETCD_NAME="master"
#ETCD_SNAPSHOT_COUNT=""
#ETCD_HEARTBEAT_INTERVAL=""
#ETCD_ELECTION_TIMEOUT=""
#ETCD_QUOTA_BACKEND_BYTES=""
#ETCD_MAX_REQUEST_BYTES=""
#ETCD_GRPC_KEEPALIVE_MIN_TIME="5s"
#ETCD_GRPC_KEEPALIVE_INTERVAL="2h0m0s"
#ETCD_GRPC_KEEPALIVE_TIMEOUT="20s" #
#[Clustering]
#ETCD_INITIAL_ADVERTISE_PEER_URLS="http://localhost:2380"
ETCD_ADVERTISE_CLIENT_URLS="http://120.27.15.116:2379,http://120.27.15.116:4001"
#ETCD_DISCOVERY=""
#ETCD_DISCOVERY_FALLBACK="proxy"
#ETCD_DISCOVERY_PROXY=""
#ETCD_DISCOVERY_SRV=""
#ETCD_INITIAL_CLUSTER="default=http://localhost:2380"
#ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster"
#ETCD_INITIAL_CLUSTER_STATE="new"
#ETCD_STRICT_RECONFIG_CHECK="true"
#ETCD_ENABLE_V2="true"
#
#[Proxy]
#ETCD_PROXY="off"
#ETCD_PROXY_FAILURE_WAIT=""
#ETCD_PROXY_REFRESH_INTERVAL=""
#ETCD_PROXY_DIAL_TIMEOUT=""
#ETCD_PROXY_WRITE_TIMEOUT=""
#ETCD_PROXY_READ_TIMEOUT=""
#
#[Security]
#ETCD_CERT_FILE=""
#ETCD_KEY_FILE=""
#ETCD_CLIENT_CERT_AUTH="false"
#ETCD_TRUSTED_CA_FILE=""
#ETCD_AUTO_TLS="false"
#ETCD_PEER_CERT_FILE=""
#ETCD_PEER_KEY_FILE=""
#ETCD_PEER_CLIENT_CERT_AUTH="false"
#ETCD_PEER_TRUSTED_CA_FILE=""
#ETCD_PEER_AUTO_TLS="false"
#
#[Logging]
#ETCD_DEBUG="false"
#ETCD_LOG_PACKAGE_LEVELS=""
#ETCD_LOG_OUTPUT="default"
#
#[Unsafe]
#ETCD_FORCE_NEW_CLUSTER="false"
#
#[Version]
#ETCD_VERSION="false"
#ETCD_AUTO_COMPACTION_RETENTION=""
#
#[Profiling]
#ETCD_ENABLE_PPROF="false"
#ETCD_METRICS="basic"
#
#[Auth]
#ETCD_AUTH_TOKEN="simple"
启动etcd，然后测试：
systemctl enable etcd
systemctl start etcd
分别存入一个值{test/key1:123}进行测试
etcdctl set test/key1 123
etcd get test/key1
[root@alta-sz etcd]# etcdctl set test/key1 [root@alta-sz etcd]# etcdctl get test/key1 [root@alta-sz etcd]#
[root@alta-sz etcd]#
[root@alta-sz etcd]#
[root@alta-sz etcd]# etcdctl -C http://localhost:2379 cluster-health
member 8e9e05c52164694d is healthy: got healthy result from http://localhost:2379
cluster is healthy
以上说明etcd安装成功了！
step2、Master节点安装Kubernetes
执行：yum install kubernetes -y
[root@alta-sz k8s]# yum install kubernetes -y
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
Resolving Dependencies
--> Running transaction check
---> Package kubernetes.x86_64 :1.5.-0.7.git269f928.el7 will be installed
--> Processing Dependency: kubernetes-node = 1.5.-0.7.git269f928.el7 for package: kubernetes-1.5.-0.7.git269f928.el7.x86_64
--> Processing Dependency: kubernetes-master = 1.5.-0.7.git269f928.el7 for package: kubernetes-1.5.-0.7.git269f928.el7.x86_64
--> Running transaction check
---> Package kubernetes-master.x86_64 :1.5.-0.7.git269f928.el7 will be installed
--> Processing Dependency: kubernetes-client = 1.5.-0.7.git269f928.el7 for package: kubernetes-master-1.5.-0.7.git269f928.el7.x86_64
---> Package kubernetes-node.x86_64 :1.5.-0.7.git269f928.el7 will be installed
--> Processing Dependency: socat for package: kubernetes-node-1.5.-0.7.git269f928.el7.x86_64
--> Processing Dependency: conntrack-tools for package: kubernetes-node-1.5.-0.7.git269f928.el7.x86_64
--> Running transaction check
---> Package conntrack-tools.x86_64 :1.4.-.el7_3 will be installed
--> Processing Dependency: libnetfilter_cttimeout.so.(LIBNETFILTER_CTTIMEOUT_1.)(64bit) for package: conntrack-tools-1.4.-.el7_3.x86_64
--> Processing Dependency: libnetfilter_cttimeout.so.(LIBNETFILTER_CTTIMEOUT_1.)(64bit) for package: conntrack-tools-1.4.-.el7_3.x86_64
--> Processing Dependency: libnetfilter_cthelper.so.(LIBNETFILTER_CTHELPER_1.)(64bit) for package: conntrack-tools-1.4.-.el7_3.x86_64
--> Processing Dependency: libnetfilter_queue.so.()(64bit) for package: conntrack-tools-1.4.-.el7_3.x86_64
--> Processing Dependency: libnetfilter_cttimeout.so.()(64bit) for package: conntrack-tools-1.4.-.el7_3.x86_64
--> Processing Dependency: libnetfilter_cthelper.so.()(64bit) for package: conntrack-tools-1.4.-.el7_3.x86_64
---> Package kubernetes-client.x86_64 :1.5.-0.7.git269f928.el7 will be installed
---> Package socat.x86_64 :1.7.3.2-.el7 will be installed
--> Running transaction check
---> Package libnetfilter_cthelper.x86_64 :1.0.-.el7 will be installed
---> Package libnetfilter_cttimeout.x86_64 :1.0.-.el7 will be installed
---> Package libnetfilter_queue.x86_64 :1.0.-.el7_2 will be installed
--> Finished Dependency Resolution Dependencies Resolved ========================================================================================================================================================================
Package Arch Version Repository Size
========================================================================================================================================================================
Installing:
kubernetes x86_64 1.5.-0.7.git269f928.el7 extras k
Installing for dependencies:
conntrack-tools x86_64 1.4.-.el7_3 base k
kubernetes-client x86_64 1.5.-0.7.git269f928.el7 extras M
kubernetes-master x86_64 1.5.-0.7.git269f928.el7 extras M
kubernetes-node x86_64 1.5.-0.7.git269f928.el7 extras M
libnetfilter_cthelper x86_64 1.0.-.el7 base k
libnetfilter_cttimeout x86_64 1.0.-.el7 base k
libnetfilter_queue x86_64 1.0.-.el7_2 base k
socat x86_64 1.7.3.2-.el7 base k Transaction Summary
========================================================================================================================================================================
Install Package (+ Dependent packages) Total download size: M
Installed size: M
Downloading packages:
(/): kubernetes-1.5.-0.7.git269f928.el7.x86_64.rpm | kB ::
(/): conntrack-tools-1.4.-.el7_3.x86_64.rpm | kB ::
(/): kubernetes-client-1.5.-0.7.git269f928.el7.x86_64.rpm | MB ::
(/): libnetfilter_cttimeout-1.0.-.el7.x86_64.rpm | kB ::
(/): libnetfilter_cthelper-1.0.-.el7.x86_64.rpm | kB ::
(/): libnetfilter_queue-1.0.-.el7_2.x86_64.rpm | kB ::
(/): kubernetes-node-1.5.-0.7.git269f928.el7.x86_64.rpm | MB ::
(/): socat-1.7.3.2-.el7.x86_64.rpm | kB ::
(/): kubernetes-master-1.5.-0.7.git269f928.el7.x86_64.rpm | MB ::
------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Total MB/s | MB ::
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
Installing : kubernetes-client-1.5.-0.7.git269f928.el7.x86_64 /
Installing : kubernetes-master-1.5.-0.7.git269f928.el7.x86_64 /
Installing : socat-1.7.3.2-.el7.x86_64 /
Installing : libnetfilter_cthelper-1.0.-.el7.x86_64 /
Installing : libnetfilter_queue-1.0.-.el7_2.x86_64 /
Installing : libnetfilter_cttimeout-1.0.-.el7.x86_64 /
Installing : conntrack-tools-1.4.-.el7_3.x86_64 /
Installing : kubernetes-node-1.5.-0.7.git269f928.el7.x86_64 /
Installing : kubernetes-1.5.-0.7.git269f928.el7.x86_64 /
Verifying : libnetfilter_cttimeout-1.0.-.el7.x86_64 /
Verifying : libnetfilter_queue-1.0.-.el7_2.x86_64 /
Verifying : kubernetes-node-1.5.-0.7.git269f928.el7.x86_64 /
Verifying : kubernetes-client-1.5.-0.7.git269f928.el7.x86_64 /
Verifying : kubernetes-master-1.5.-0.7.git269f928.el7.x86_64 /
Verifying : libnetfilter_cthelper-1.0.-.el7.x86_64 /
Verifying : conntrack-tools-1.4.-.el7_3.x86_64 /
Verifying : socat-1.7.3.2-.el7.x86_64 /
Verifying : kubernetes-1.5.-0.7.git269f928.el7.x86_64 / Installed:
kubernetes.x86_64 :1.5.-0.7.git269f928.el7 Dependency Installed:
conntrack-tools.x86_64 :1.4.-.el7_3 kubernetes-client.x86_64 :1.5.-0.7.git269f928.el7 kubernetes-master.x86_64 :1.5.-0.7.git269f928.el7
kubernetes-node.x86_64 :1.5.-0.7.git269f928.el7 libnetfilter_cthelper.x86_64 :1.0.-.el7 libnetfilter_cttimeout.x86_64 :1.0.-.el7
libnetfilter_queue.x86_64 :1.0.-.el7_2 socat.x86_64 :1.7.3.2-.el7 Complete!
安装完成可以分别查看如下目录文件：
step3、配置Master节点，Master节点需要配置config、apiserver、controller-manager、schduler
1、config配置:vi /etc/kubernetes/config 主要配置其中的参数KUBE_MASTER
2、apiserver配置：vi /etc/kubernetes/apiserver
参数说明：
KUBE_API_ADDRESS:ApiServer监听IP地址，配置为0.0.0.0，监听所有
KUBE_API_PORT:ApIServer监听端口
KUBE_ETCD_SERVERS:ETCD存储服务器IP+PORT
3、controller-manager配置:保持默认即可
4、schduler配置:保持默认即可
step4、启动Master节点
启动apiserver:
systemctl enable kube-apiserver.service
systemctl start kube-apiserver.service
启动controller-manager:
systemctl enable kube-controller-manager.service
systemctl start kube-controller-manager.service
启动scheduler:
systemctl enable kube-scheduler.service
systemctl start kube-scheduler.service
至此，Master节点就安装完成了，下面继续Node节点的安装。
step5、安装Node节点
yum install kubernetes -y 安装和Master的步骤相同
step6、配置Node节点、Node节点需要配置config、kubelet、proxy
1、配置config:vi /etc/kubernetes/config
2、配置kubelet:vi /etc/kubernetes/kublet
3、配置proxy:保持默认即可
step7、启动Node节点
启动kubelet:
systemctl enable kubelet.service
systemctl startkubelet.service
启动proxy:
systemctl enable kube-proxy.service
systemctl startkube-proxy.service
step8、测试验证
到Master节点执行：kubectl get nodes 如下，node节点成功加入到Master。
一个简单的Kubernetes集群就搭建起来了。