cat /etc/redhat-release 
Red Hat Enterprise Linux Server release 6.4 (Santiago)

=====================================================================================
cat /etc/yum.repos.d/mongodb-enterprise.repo 
[mongodb-enterprise]
name=MongoDB Enterprise Repository
baseurl=https://repo.mongodb.com/yum/redhat/6Server/mongodb-enterprise/3.4/$basearch/
gpgcheck=1
enabled=1
gpgkey=https://www.mongodb.org/static/pgp/server-3.4.asc

=====================================================================================
STEP 1:
------
[mongod@prds01 ~]$ sudo yum --installroot=/data/db/ install -y mongodb-enterprise
Loaded plugins: product-id, refresh-packagekit, security, subscription-manager
This system is receiving updates from Red Hat Subscription Management.
Setting up Install Process
https://cdn.redhat.com/content/dist/rhel/server/6/%24releasever/x86_64/os/repodata/repomd.xml: [Errno 14] PYCURL ERROR 22 - "The requested URL returned error: 404 Not Found"
Trying other mirror.
To address this issue please refer to the below knowledge base article 

https://access.redhat.com/articles/1320623
If above article doesn't help to resolve this issue please open a ticket with Red Hat Support.
Error: Cannot retrieve repository metadata (repomd.xml) for repository: rhel-6-server-rpms. Please verify its path and try again


STEP 2:
------
[root@prds01 yum.repos.d]# id mongod
uid=500(mongod) gid=500(mongod) groups=500(mongod),10(wheel)

[root@prds01 yum.repos.d]# cat /etc/redhat-release 
Red Hat Enterprise Linux Server release 6.4 (Santiago)
echo 6Server >> cat etc/yum/vars/releasever

Also modified redhat.repo by changing $releasever to 6Server, but whenever trying to run step 1, I am getting the same error.


STEP 3:
------
[root@prds01 yum.repos.d]# ll /etc/yum.repos.d
total 104
-rw-r--r--. 1 root root   221 Jan  4 02:46 mongodb-enterprise.repo
-rw-rw-r--. 1 root root 45102 Jan  4 06:14 redhat.repo
-rw-rw-r--. 1 root root 45102 Jan  4 03:44 redhat.repo.bkp.4thjan
-rw-r--r--. 1 root root   529 Jan 29  2013 rhel-source.repo
[root@prds01 yum.repos.d]# rm -fr /var/cache/yum/*
[root@prds01 yum.repos.d]# yum clean all
Loaded plugins: product-id, refresh-packagekit, security, subscription-manager
This system is receiving updates from Red Hat Subscription Management.
Cleaning repos: mongodb-enterprise rhel-6-server-rpms
Cleaning up Everything
[root@prds01 yum.repos.d]# yum repolist
Loaded plugins: product-id, refresh-packagekit, security, subscription-manager
This system is receiving updates from Red Hat Subscription Management.
mongodb-enterprise                                                                                    | 2.5 kB     00:00     
mongodb-enterprise/primary_db                                                                         |  15 kB     00:00     
rhel-6-server-rpms                                                                                    | 3.5 kB     00:00     
rhel-6-server-rpms/primary_db                                                                         |  51 MB     05:57     
repo id                                         repo name                                                              status
mongodb-enterprise                              MongoDB Enterprise Repository                                              10
rhel-6-server-rpms                              Red Hat Enterprise Linux 6 Server (RPMs)                               18,391
repolist: 18,401


------------
Again run the step 1 but issue remains.