Not sure if it is a manual issue, a build issue (or maybe user error).
I am following the instructions at
https://docs.mongodb.com/master/tutorial/install-mongodb-on-red-hat/
Note that this page is definitely "live" as it is linked from the linux 3.4 download area at https://www.mongodb.com/download-center#community.
I have created the repo file in step 1. (Note that there is a 3.3 reference in the repo file, not sure if that is intentional).
[mongodb-org-3.4] name=MongoDB Repository baseurl=https://repo.mongodb.org/yum/redhat/$releasever/mongodb-org/3.3/x86_64/ gpgcheck=1 enabled=1 gpgkey=https://www.mongodb.org/static/pgp/server-3.4.asc
Step 2 yields the following
[root@localhost vagrant]# sudo yum install -y mongodb-org-3.4-rc0 mongodb-org-server-3.4-rc0 mongodb-org-shell-3.4-rc0 mongodb-org-mongos-3.4-rc0 mongodb-org-tools-3.4-rc0 Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile * base: repos.lax.quadranet.com * extras: mirrors.unifiedlayer.com * updates: mirrors.ocf.berkeley.edu No package mongodb-org-3.4-rc0 available. No package mongodb-org-server-3.4-rc0 available. No package mongodb-org-shell-3.4-rc0 available. No package mongodb-org-mongos-3.4-rc0 available. No package mongodb-org-tools-3.4-rc0 available. Error: Nothing to do
CentOS 7 (in virtualbox)
[root@localhost vagrant]# uname -a Linux localhost.localdomain 3.10.0-327.36.1.el7.x86_64 #1 SMP Sun Sep 18 13:04:29 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux