安装并启动MongoDB

安装方法：

https://docs.mongodb.com/manual/installation/

启动方法（CentOS7的默认安装位置为/usr/bin/mongo）:

To start the mongo shell and connect to your MongoDB instance running on localhost with default port:

1. At a prompt in a terminal window (or a command prompt for Windows), go to your <mongodb installation dir>:

• cd <mongodb installation dir>

• Type ./bin/mongo to start mongo:

./bin/mongo

If you have added the <mongodb installation dir>/bin to the PATH environment variable, you can just type mongo instead of ./bin/mongo.

解决无法链接mongodb的错误：

问题：MongoDB使用技巧 无法链接mongodb，附上错误log
描述:

MongoDB shell version v3.4.2
connecting to: mongodb://127.0.0.1:27017
2017-03-01T12:06:59.013+0800 W NETWORK [thread1] Failed to connect to 127.0.0.1:27017, in(checking socket for error after poll), reason: Connection refused
2017-03-01T12:06:59.015+0800 E QUERY [thread1] Error: couldn't connect to server 127.0.0.1:27017, connection attempt failed :
connect@src/mongo/shell/mongo.js:237:13
@(connect):1:6
exception: connect failed

解决方案1:

ps -ef | grep mongo
查看有无进程
/etc/init.d/mongod start

解决方案2:

先尝试重启mongodb：

sudo service mongod restart

如果不行，则删除数据目录(默认数据目录为/var/lib/mongodb)下的mongod.lock文件，重试上步

解决方案3:

使用mongod 命令先启动本地的mongo服务