在centOS（CentOS Linux版本7.4.1708（核心））上安装nagios时得到以下错误。如何解决这些问题？
Error: php72u-common conflicts with php56u-common-5.6.37-1.ius.centos7.x86_64
Error: php72u-pdo conflicts with php56u-pdo-5.6.37-1.ius.centos7.x86_64
Error: Package: perl-Mail-IMAPClient-3.37-1.el7.noarch (epel)
Requires: perl(Parse::RecDescent)
Error: php72u-xml conflicts with php56u-xml-5.6.37-1.ius.centos7.x86_64
Error: Package: rrdtool-1.4.9-1.el7.x86_64 (nagiosxi-deps)
Requires: dejavu-lgc-sans-mono-fonts
Error: php72u-cli conflicts with php56u-cli-5.6.37-1.ius.centos7.x86_64
Error: Package: nagiosxi-deps-el7-5.5.3-1.noarch (/nagiosxi-deps-el7-5.5.3-1.noarch)
Requires: net-snmp-perl
Error: Package: nagiosxi-deps-el7-5.5.3-1.noarch (/nagiosxi-deps-el7-5.5.3-1.noarch)
Requires: gd-devel
Error: Package: dejavu-lgc-sans-fonts-2.33-1.el6.noarch (installed)
Requires: dejavu-fonts-common = 2.33-1.el6
Removing: dejavu-fonts-common-2.33-1.el6.noarch (installed)
dejavu-fonts-common = 2.33-1.el6
Updated By: dejavu-fonts-common-2.33-6.el7.noarch (RHEL7_u4)
dejavu-fonts-common = 2.33-6.el7