user@sandbox:~$ sudo systemctl enable mongod.service
Created symlink from /etc/systemd/system/multi-user.target.wants/mongod.service to /lib/systemd/system/mongod.service.
user@sandbox:~$ sudo systemctl start mongod.service
user@sandbox:~$ mongo
MongoDB shell version v3.4.2
connecting to: mongodb://127.0.0.1:27017
MongoDB server version: 3.4.2
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: 
2017-02-17T15:14:31.249+0100 I STORAGE  [initandlisten] 
2017-02-17T15:14:31.249+0100 I STORAGE  [initandlisten] ** WARNING: Using the XFS filesystem is strongly recommended with the WiredTiger storage engine
2017-02-17T15:14:31.249+0100 I STORAGE  [initandlisten] **          See http://dochub.mongodb.org/core/prodnotes-filesystem
2017-02-17T15:14:31.917+0100 I CONTROL  [initandlisten] 
2017-02-17T15:14:31.917+0100 I CONTROL  [initandlisten] ** WARNING: Access control is not enabled for the database.
2017-02-17T15:14:31.917+0100 I CONTROL  [initandlisten] **          Read and write access to data and configuration is unrestricted.
2017-02-17T15:14:31.917+0100 I CONTROL  [initandlisten] 
2017-02-17T15:14:31.917+0100 I CONTROL  [initandlisten] 
2017-02-17T15:14:31.917+0100 I CONTROL  [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'.
2017-02-17T15:14:31.917+0100 I CONTROL  [initandlisten] **        We suggest setting it to 'never'
2017-02-17T15:14:31.917+0100 I CONTROL  [initandlisten] 
> ^C
bye

user@sandbox:~$ sudo apt-get remove --purge mongodb-org-server
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages were automatically installed and are no longer required:
  mongodb-org-mongos mongodb-org-shell mongodb-org-tools
Use 'apt-get autoremove' to remove them.
The following packages will be REMOVED:
  mongodb-org* mongodb-org-server*
0 upgraded, 0 newly installed, 2 to remove and 22 not upgraded.
After this operation, 54.5 MB disk space will be freed.
Do you want to continue? [Y/n] 
(Reading database ... 40192 files and directories currently installed.)
Removing mongodb-org (3.4.2) ...
Purging configuration files for mongodb-org (3.4.2) ...
dpkg: warning: while removing mongodb-org, directory '/var/lib/mongodb' not empty so not removed
Removing mongodb-org-server (3.4.2) ...
Purging configuration files for mongodb-org-server (3.4.2) ...
Processing triggers for man-db (2.7.0.2-5) ...

user@sandbox:~$ mongo
MongoDB shell version v3.4.2
connecting to: mongodb://127.0.0.1:27017
MongoDB server version: 3.4.2
Server has startup warnings: 
2017-02-17T15:14:31.249+0100 I STORAGE  [initandlisten] 
2017-02-17T15:14:31.249+0100 I STORAGE  [initandlisten] ** WARNING: Using the XFS filesystem is strongly recommended with the WiredTiger storage engine
2017-02-17T15:14:31.249+0100 I STORAGE  [initandlisten] **          See http://dochub.mongodb.org/core/prodnotes-filesystem
2017-02-17T15:14:31.917+0100 I CONTROL  [initandlisten] 
2017-02-17T15:14:31.917+0100 I CONTROL  [initandlisten] ** WARNING: Access control is not enabled for the database.
2017-02-17T15:14:31.917+0100 I CONTROL  [initandlisten] **          Read and write access to data and configuration is unrestricted.
2017-02-17T15:14:31.917+0100 I CONTROL  [initandlisten] 
2017-02-17T15:14:31.917+0100 I CONTROL  [initandlisten] 
2017-02-17T15:14:31.917+0100 I CONTROL  [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'.
2017-02-17T15:14:31.917+0100 I CONTROL  [initandlisten] **        We suggest setting it to 'never'
2017-02-17T15:14:31.917+0100 I CONTROL  [initandlisten] 
>