linux下启动mongodb的时候报这个错误：Failed to start mongod.service: Unit not found

1创建配置文件：

sudo nano /etc/systemd/system/mongodb.service

2.在里面追加文本：

 1 [Unit]
 2 Description=High-performance, schema-free document-oriented database
 3 After=network.target
 4  
 5 [Service]
 6 User=mongodb
 7 ExecStart=/usr/bin/mongod --quiet --config /etc/mongod.conf
 8  
 9 [Install]
10 WantedBy=multi-user.target

 1 [Unit]
 2 Description=High-performance, schema-free document-oriented database
 3 After=network.target
 4  
 5 [Service]
 6 User=mongodb
 7 ExecStart=/usr/bin/mongod --quiet --config /etc/mongod.conf
 8  
 9 [Install]
10 WantedBy=multi-user.target

3.按ctrl+X退出

4.启动服务

sudo systemctl start mongodb
sudo systemctl status mongodb

sudo systemctl start mongodb
sudo systemctl status mongodb

5.让它永久启动

sudo systemctl enable mongodb