Install MongoDB 4 on Debian 9

You can see detailed instruction on how to install on MongoDB web site.

First add key

apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 9DA31620334BD75D9DCB49F368818C72E52529D4

For Debian 8, run

echo "deb http://repo.mongodb.org/apt/debian jessie/mongodb-org/4.0 main" > /etc/apt/sources.list.d/mongodb-org-4.0.list

For Debian 9, run

echo "deb http://repo.mongodb.org/apt/debian stretch/mongodb-org/4.0 main" > /etc/apt/sources.list.d/mongodb-org-4.0.list

Now install mongoDB with

apt-get update
apt-get install -y mongodb-org

Once installed, you can check version with

root@ip-172-31-25-155:~# mongod --version
db version v4.0.4
git version: f288a3bdf201007f3693c58e140056adf8b04839
OpenSSL version: OpenSSL 1.1.0f  25 May 2017
allocator: tcmalloc
modules: none
build environment:
    distmod: debian92
    distarch: x86_64
    target_arch: x86_64
root@ip-172-31-25-155:~# 

Enable MongoDB start on boot

systemctl enable mongod

To start/stop mongodb

systemctl start mongod
systemctl stop mongod