I looked at a lot of resources, but I couldn't find any useful information. Either repos are broken or prepug problems...
I/O warning : failed to load external entity
"/usr/share/openscap/xsl/security-guide.xsl" compilation error: file
/usr/share/preupgrade/xsl/preup.xsl line 40 element import xsl:import
: unable to load /usr/share/openscap/xsl/security-guide.xsl I/O
warning : failed to load external entity
"/usr/share/openscap/xsl/oval-report.xsl" compilation error: file
/usr/share/preupgrade/xsl/preup.xsl line 41 element import xsl:import
: unable to load /usr/share/openscap/xsl/oval-report.xsl I/O warning :
failed to load external entity
"/usr/share/openscap/xsl/sce-report.xsl" compilation error: file
/usr/share/preupgrade/xsl/preup.xsl line 42 element import xsl:import
: unable to load /usr/share/openscap/xsl/sce-report.xsl OpenSCAP
Error:: Could not parse XSLT file
'/usr/share/preupgrade/xsl/preup.xsl' [oscapxml.c:416] Unable to open
file /root/preupgrade/result.html Usage: preupg [options]
preupg: error: [Errno 2] No such file or directory:
'/root/preupgrade/result.html' [root@localhost upgrade]# yum
localinstall redhat-upgrade-tool-0.7.22-3.el6.centos.noarch.rpm Failed
to set locale, defaulting to C Loaded plugins: fastestmirror Setting
up Local Package Process Examining
redhat-upgrade-tool-0.7.22-3.el6.centos.noarch.rpm:
1:redhat-upgrade-tool-0.7.22-3.el6.centos.noarch
redhat-upgrade-tool-0.7.22-3.el6.centos.noarch.rpm: does not update
installed package. Nothing to do [root@localhost upgrade]# rpm
--import http://ftp.plusline.de/centos/7.0.1406/os/x86_64/RPM-GPG-KEY-CentOS-7
curl: (22) The requested URL returned error: 404 Not Found error:
http://ftp.plusline.de/centos/7.0.1406/os/x86_64/RPM-GPG-KEY-CentOS-7:
import read failed(2). [root@localhost upgrade]# [root@localhost
upgrade]# rpm --import
http://isoredirect.centos.org/centos/7/os/x86_64/RPM-GPG-KEY-CentOS-7
curl: (22) The requested URL returned error: 404 Not Found error:
http://isoredirect.centos.org/centos/7/os/x86_64/RPM-GPG-KEY-CentOS-7:
import read failed(2).
Copyright Notice：Content Author:「Ersel Bey」，Reproduced under the CC 4.0 BY-SA copyright license with a link to the original source and this disclaimer.
Link to original article：https://stackoverflow.com/questions/54905101/centos-6-x-6-10-to-centos-7-x