Step 1: Remove any previous repository

sudo rm -rf /etc/yum.repos.d/mongod*
sudo yum clean all

Step 2: create new repo file

sudo vi /etc/yum.repos.d/mongodb-org-3.4.repo

Copy and paste below lines in mongodb-org-3.4.repo

[mongodb-org-3.4]
name=MongoDB Repository
baseurl=https://repo.mongodb.org/yum/amazon/2013.03/mongodb-org/3.4/x86_64/
gpgcheck=1
enabled=1
gpgkey=https://www.mongodb.org/static/pgp/server-3.4.asc

Save repo file and exit

Step 3: sudo yum install -y mongodb-org

Step 4 : service mongod start

Step 5 : Check mongod running status

service mongod status

Step 6: To ensure mongo will restart automatically on reboot

sudo chkconfig mongod on