1.去官网下载安装包 mongodb-osx-x86_64-3.4.9.tgz 版本
2.解压出来，放到自己的文件夹下例如：/mongodb/mongodb3.4/
3.在/mongodb/下新建data/db，mongodb的数据库的位置
4.授权文件夹 sudo chmod -R 777 data
5.配置环境变量 vi ~/.bash_profile export Mongodb=/Users/xxxx/mongodb3.4/mongodb/bin:$PATH ，xxxx是我机器的用户名,source ~/.bash_profile 让环境变量生效。
6.然后启动mongodb：cd /Users/xxxx/mongodb3.4/mongodb/bin ---> sudo ./mongod --rest 出现如下图的日志
2017-11-02T11:28:26.426+0800 I CONTROL [main] ** WARNING: --rest is specified without --httpinterface,
2017-11-02T11:28:26.426+0800 I CONTROL [main] ** enabling http interface
2017-11-02T11:28:26.498+0800 I CONTROL [initandlisten] MongoDB starting : pid=7572 port=27017 dbpath=/data/db 64-bit host=bogon
2017-11-02T11:28:26.498+0800 I CONTROL [initandlisten] db version v3.4.9
2017-11-02T11:28:26.498+0800 I CONTROL [initandlisten] git version: 876ebee8c7dd0e2d992f36a848ff4dc50ee6603e
2017-11-02T11:28:26.498+0800 I CONTROL [initandlisten] OpenSSL version: OpenSSL 0.9.8zh 14 Jan 2016
2017-11-02T11:28:26.498+0800 I CONTROL [initandlisten] allocator: system
2017-11-02T11:28:26.498+0800 I CONTROL [initandlisten] modules: none
2017-11-02T11:28:26.498+0800 I CONTROL [initandlisten] build environment:
2017-11-02T11:28:26.498+0800 I CONTROL [initandlisten] distarch: x86_64
2017-11-02T11:28:26.498+0800 I CONTROL [initandlisten] target_arch: x86_64
2017-11-02T11:28:26.498+0800 I CONTROL [initandlisten] options: { net: { http: { RESTInterfaceEnabled: true, enabled: true } } }
2017-11-02T11:28:26.502+0800 I STORAGE [initandlisten] exception in initAndListen: 29 Data directory /data/db not found., terminating
2017-11-02T11:28:26.502+0800 I NETWORK [initandlisten] shutdown: going to close listening sockets...
2017-11-02T11:28:26.502+0800 I NETWORK [initandlisten] shutdown: going to flush diaglog...
2017-11-02T11:28:26.502+0800 I CONTROL [initandlisten] now exiting
2017-11-02T11:28:26.502+0800 I CONTROL [initandlisten] shutting down with code:100
这说明启动失败了，通过exception in initAndListen: 29 Data directory /data/db not found., terminating可以看出来，mongodb找不到/data/db 之前不是创建了这样的文件夹吗，为什么找不到，不要着急 执行命令：sudo ./mongod --dbpath /Users/xxxx/mongodb3.4/data/db 然后再执行sudo ./mongod --rest，ok启动了，没问题了
日志如下：
2017-11-02T11:35:36.341+0800 I CONTROL [initandlisten] MongoDB starting : pid=7808 port=27017 dbpath=/Users/xxxx/mongodb3.4/data/db 64-bit host=bogon
2017-11-02T11:35:36.341+0800 I CONTROL [initandlisten] db version v3.4.9
2017-11-02T11:35:36.341+0800 I CONTROL [initandlisten] git version: 876ebee8c7dd0e2d992f36a848ff4dc50ee6603e
2017-11-02T11:35:36.341+0800 I CONTROL [initandlisten] OpenSSL version: OpenSSL 0.9.8zh 14 Jan 2016
2017-11-02T11:35:36.341+0800 I CONTROL [initandlisten] allocator: system
2017-11-02T11:35:36.341+0800 I CONTROL [initandlisten] modules: none
2017-11-02T11:35:36.341+0800 I CONTROL [initandlisten] build environment:
2017-11-02T11:35:36.341+0800 I CONTROL [initandlisten] distarch: x86_64
2017-11-02T11:35:36.341+0800 I CONTROL [initandlisten] target_arch: x86_64
2017-11-02T11:35:36.341+0800 I CONTROL [initandlisten] options: { storage: { dbPath: "/Users/xxxx/mongodb3.4/data/db" } }
2017-11-02T11:35:36.344+0800 I STORAGE [initandlisten] wiredtiger_open config: create,cache_size=1536M,session_max=20000,eviction=(threads_min=4,threads_max=4),config_base=false,statistics=(fast),log=(enabled=true,archive=true,path=journal,compressor=snappy),file_manager=(close_idle_time=100000),checkpoint=(wait=60,log_size=2GB),statistics_log=(wait=0),.......