一、简介
etcd是一个分布式一致性键值存储，其主要用于分布式系统的共享配置和服务发现。
etcd由Go语言编写
二、下载并安装
1.下载地址：
https://github.com/coreos/etcd/releases
2. 将压缩文件解压到指定文件夹
解压后的目录如下：
其中etcd.exe是服务端，etcdctl.exe是客户端
二、简单实用
1. 点击etcd.exe运行etcd服务
2. 客户端是有etcdctl来执行命令的
1）帮助文档
在安装目录命令提示符中执行 etcdctl help 可以查看etcdctl的基本命令如下：
NAME:
etcdctl - A simple command line client for etcd.
USAGE:
etcdctl [global options] command [command options] [arguments...]
VERSION:
3.3.8
COMMANDS:
backup backup an etcd directory
cluster-health check the health of the etcd cluster
mk make a new key with a given value
mkdir make a new directory
rm remove a key or a directory
rmdir removes the key if it is an empty directory or a key-value pair
get retrieve the value of a key
ls retrieve a directory
set set the value of a key
setdir create a new directory or update an existing directory TTL
update update an existing key with a given value
updatedir update an existing directory
watch watch a key for changes
exec-watch watch a key for changes and exec an executable
member member add, remove and list subcommands
user user add, grant and revoke subcommands
role role add, grant and revoke subcommands
auth overall auth controls
help, h Shows a list of commands or help for one command
GLOBAL OPTIONS:
--debug output cURL commands which can be used to reproduce the request
--no-sync don't synchronize cluster information before sending request
--output simple, -o simple output response in the given format (simple, `extended` or `json`) (default: "simple")
--discovery-srv value, -D value domain name to query for SRV records describing cluster endpoints
--insecure-discovery accept insecure SRV records describing cluster endpoints
--peers value, -C value DEPRECATED - "--endpoints" should be used instead
--endpoint value DEPRECATED - "--endpoints" should be used instead
--endpoints value a comma-delimited list of machine addresses in the cluster (default: "http://127.0.0.1:2379,http://127.0.0.1:4001")
--cert-file value identify HTTPS client using this SSL certificate file
--key-file value identify HTTPS client using this SSL key file
--ca-file value verify certificates of HTTPS-enabled servers using this CA bundle
--username value, -u value provide username[:password] and prompt if password is not supplied.
--timeout value connection timeout per request (default: 2s)
--total-timeout value timeout for the command execution (except watch) (default: 5s)
--help, -h show help
--version, -v print the version
2）查看版本号 etcdctl --version
3) 由于文档中建议API version的版本设为3
设置版本set ETCDCTL_API=3
即可设置API version,设置成功后etcdctl help查看版本3和2命令和功能方面有不少的差别
3）通过put和get 存取值
存取key为hello，value为world
获取key为hello的值