CentOS

# yum whatprovides scl-util*
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* base: mirror.calgah.com
* epel: fedora-epel.mirror.iweb.com
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scl-utils-20120927-29.el6_9.x86_64 : Utilities for alternative packaging
Repo : base
Matched from:
Other : scl-utils = 20120927-29.el6_9
Other : scl-utils(x86-64) = 20120927-29.el6_9



scl-utils-build-20120927-29.el6_9.x86_64 : RPM build macros for alternative packaging
Repo : base
Matched from:
Other : scl-utils-build(x86-64) = 20120927-29.el6_9
Other : scl-utils-build = 20120927-29.el6_9



scl-utils-20130529-17.el7_1.x86_64 : Utilities for alternative packaging
Repo : centos6
Matched from:
Other : scl-utils(x86-64) = 20130529-17.el7_1
Other : scl-utils = 20130529-17.el7_1



scl-utils-build-20130529-17.el7_1.x86_64 : RPM build macros for alternative packaging
Repo : centos6
Matched from:
Other : scl-utils-build = 20130529-17.el7_1
Other : scl-utils-build(x86-64) = 20130529-17.el7_1



scl-utils-20120927-27.el6_6.x86_64 : Utilities for alternative packaging
Repo : centos6
Matched from:
Other : scl-utils(x86-64) = 20120927-27.el6_6
Other : scl-utils = 20120927-27.el6_6



scl-utils-build-20120927-27.el6_6.x86_64 : RPM build macros for alternative packaging
Repo : centos6
Matched from:
Other : scl-utils-build = 20120927-27.el6_6
Other : scl-utils-build(x86-64) = 20120927-27.el6_6



scl-utils-20120927-29.el6_9.x86_64 : Utilities for alternative packaging
Repo : centos6
Matched from:
Other : scl-utils = 20120927-29.el6_9
Other : scl-utils(x86-64) = 20120927-29.el6_9



scl-utils-build-20120927-29.el6_9.x86_64 : RPM build macros for alternative packaging
Repo : centos6
Matched from:
Other : scl-utils-build(x86-64) = 20120927-29.el6_9
Other : scl-utils-build = 20120927-29.el6_9



scl-utils-20120229-1.el6.x86_64 : Utilities for alternative packaging
Repo : epel
Matched from:
Other : scl-utils(x86-64) = 20120229-1.el6
Other : scl-utils = 20120229-1.el6



scl-utils-build-20120229-1.el6.x86_64 : RPM build macros for alternative packaging
Repo : epel
Matched from:
Other : scl-utils-build = 20120229-1.el6
Other : scl-utils-build(x86-64) = 20120229-1.el6



if you look in the list you will see
scl-utils-20130529-17.el7_1.x86_64 and scl-utils-build-20130529-17.el7_1.x86_64 from centos6 repo

This cause yum to fail to install because the package expecting glibc 2.14 + which is not available by default
EL7 package should not be there at all

Thank you.

scl-utils-20130529-17.el7_1.x86_64 and scl-utils-build-20130529-17.el7_1.x86_64 from centos6 repo

We do not supply either of those. This is the output from your yum whatprovides here on an unmodified CentOS 6 system pointing to CentOS repos

scl-utils-20120927-29.el6_9.x86_64 : Utilities for alternative packaging
Repo : base
Matched from:
Other : scl-utils = 20120927-29.el6_9
Other : scl-utils(x86-64) = 20120927-29.el6_9



scl-utils-build-20120927-29.el6_9.x86_64 : RPM build macros for alternative packaging
Repo : base
Matched from:
Other : scl-utils-build(x86-64) = 20120927-29.el6_9
Other : scl-utils-build = 20120927-29.el6_9

Your problem ones appear to be for CentOS 7 ... el7_1.x86_64!

Yeah, after further investigation, found that the repo "centos6" is in fact spacewalk

sorry for this