reference:http://dblab.xmu.edu.cn/blog/868-2/

root@iZuf68496ttdogcxs22w6sZ:~# mv mongodb-linux-x86_64-ubuntu1604-3.2.7.tgz /usr/local/
root@iZuf68496ttdogcxs22w6sZ:~# su hadoop

hadoop@iZuf68496ttdogcxs22w6sZ:/usr/local$ sudo tar zxf mongodb-linux-x86_64-ubuntu1604-3.2.7.tgz -C /usr/local/
[sudo] password for hadoop:

hadoop@iZuf68496ttdogcxs22w6sZ:/usr/local$ sudo mv mongodb-linux-x86_64-ubuntu1604-3.2.7 mongodb
hadoop@iZuf68496ttdogcxs22w6sZ:/usr/local$ sudo chown -R hadoop:hadoop mongodb
hadoop@iZuf68496ttdogcxs22w6sZ:/usr/local$ cd mongodb/
hadoop@iZuf68496ttdogcxs22w6sZ:/usr/local/mongodb$ ls
bin GNU-AGPL-3.0 MPL-2 README THIRD-PARTY-NOTICES
hadoop@iZuf68496ttdogcxs22w6sZ:/usr/local/mongodb$ mkdir data/db/journal -p
hadoop@iZuf68496ttdogcxs22w6sZ:/usr/local/mongodb$ ls
bin data GNU-AGPL-3.0 MPL-2 README THIRD-PARTY-NOTICES
hadoop@iZuf68496ttdogcxs22w6sZ:/usr/local/mongodb$ cd data/db/journal/
hadoop@iZuf68496ttdogcxs22w6sZ:/usr/local/mongodb/data/db/journal$ ls
hadoop@iZuf68496ttdogcxs22w6sZ:/usr/local/mongodb/data/db/journal$ touch mongodb.log

hadoop@iZuf68496ttdogcxs22w6sZ:/usr/local/mongodb/data$ cat mongodb.conf

logpath=/usr/local/mongodb/data/db/journal/mongodb.log
logappend=true
fork=true
dbpath=/usr/local/mongodb/data/db
port=27017

add export PATH=$PATH:/usr/local/mongodb/bin  to  ~/.bashrc

hadoop@iZuf68496ttdogcxs22w6sZ:/usr/local/mongodb/bin$ mongod -f ../data/mongodb.conf
about to fork child process, waiting until server is ready for connections.
forked process: 16409
child process started successfully, parent exiting
hadoop@iZuf68496ttdogcxs22w6sZ:/usr/local/mongodb/bin$ pgrep mongod -l
16409 mongod
hadoop@iZuf68496ttdogcxs22w6sZ:/usr/local/mongodb/bin$ mongo
MongoDB shell version: 3.2.7
connecting to: test
Welcome to the MongoDB shell.
For interactive help, type "help".
For more comprehensive documentation, see
http://docs.mongodb.org/
Questions? Try the support group
http://groups.google.com/group/mongodb-user
Server has startup warnings:
2019-01-28T13:43:33.783+0800 I CONTROL [initandlisten]
2019-01-28T13:43:33.783+0800 I CONTROL [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'.
2019-01-28T13:43:33.783+0800 I CONTROL [initandlisten] ** We suggest setting it to 'never'
2019-01-28T13:43:33.783+0800 I CONTROL [initandlisten]
2019-01-28T13:43:33.783+0800 I CONTROL [initandlisten] ** WARNING: soft rlimits too low. rlimits set to 7856 processes, 65535 files. Number of processes should be at least 32767.5 : 0.5 times number of files.
2019-01-28T13:43:33.783+0800 I CONTROL [initandlisten]

if we want to in-depth study mongodb , we can learn from :

http://www.runoob.com/mongodb/mongodb-connections.html