yum update -y
Loaded plugins: product-id, protectbase, rhnplugin, security, subscription manager:
Updating certificate-based repositories.
Unable to read consumer identity
0 packages excluded due to repository protections
Setting up Update Process
Resolving Dependencies
--> Running transaction check
...<snip>

How do I get rid of this warning /error under RHEL 6 server?


You need to edit the following files

[a] /etc/yum/pluginconf.d/subscription-manager.conf

[b] /etc/yum/pluginconf.d/product-id.conf

Use a text editor such as vi:
# vi /etc/yum/pluginconf.d/product-id.conf /etc/yum/pluginconf.d/subscription-manager.conf
Set enabled to 0 as follows in both files:

[main]
enabled=0

Save and close the file. Finally, type the following command to clean cache:

rm -rfv /var/cache/yum/*
yum clean all

You can now install or update the system:
# yum install packageNameHere
OR
# yum -y update

Reference

As per RHEL KB # 165803 root cause for this error was:

When RHN Classic or RHN Satellite is used for updating the system, subscription-manager should be disabled.