If you didn’t register your RHEL instance on install (you only get one chance after installation and reboot). You’ll likely see the following type of messages when you go to use yum for anything.
[root@rhel74 yum.repos.d]# yum repolist all
Loaded plugins: langpacks, product-id, search-disabled-repos, subscription-
: manager
This system is not registered with an entitlement server. You can use subscription-manager to register.
repolist: 0
[root@rhel74 yum.repos.d]# subscription-manager register –username XXXXX –password XXXXX
Registering to: subscription.rhsm.redhat.com:443/subscription
The system has been registered with ID: 4551febe-eb44-4aa9-9e2b-XXXXXX
[root@rhel74 yum.repos.d]# yum repolist all
Loaded plugins: langpacks, product-id, search-disabled-repos, subscription-
: manager
This system is registered with an entitlement server, but is not receiving updates. You can use subscription-manager to assign subscriptions.
repolist: 0
[root@rhel74 yum.repos.d]# subscription-manager attach –auto
Installed Product Current Status:
Product Name: Red Hat Enterprise Linux Server
Status: Subscribed
[root@rhel74 yum.repos.d]# yum repolist all
Loaded plugins: langpacks, product-id, search-disabled-repos, subscription-
: manager
rhel-7-server-rpms | 3.5 kB 00:00
rhel-7-server-rt-rpms | 4.0 kB 00:00
(1/6): rhel-7-server-rpms/7Server/x86_64/group | 709 kB 00:00
(2/6): rhel-7-server-rpms/7Server/x86_64/updateinfo | 2.5 MB 00:00
(3/6): rhel-7-server-rt-rpms/7Server/x86_64/group | 1.8 kB 00:00
(4/6): rhel-7-server-rt-rpms/7Server/x86_64/primary_db | 113 kB 00:00
(5/6): rhel-7-server-rt-rpms/7Server/x86_64/updateinfo | 71 kB 00:01
(6/6): rhel-7-server-rpms/7Server/x86_64/primary_db | 47 MB 00:03
Now – if you are like me – all of these are NOT enabled. To enable them:
# vi /etc/yum.repos.d/redhat.repo and set enabled=1 for those