We require some dependencies from the EPEL repository itself, so make sure to enable it.
yum install epel-release
On CentOS 7 Icinga Web 2 will also require PHP via the SCL repository system:
yum install centos-release-scl
wget https://packages.icinga.com/centos/ICINGA-release.repo -O /etc/yum.repos.d/ICINGA-release.repo
WARNING: These are pre release builds which are not recommended for production use. If you're setting up a production system please use the release packages instead.
wget https://packages.icinga.com/centos/ICINGA-testing.repo -O /etc/yum.repos.d/ICINGA-testing.repo
WARNING: These are auto-built packages, based on current development trees.
Made only for testing purposes, you should not use them in production environments!
wget https://packages.icinga.com/centos/ICINGA-snapshot.repo -O /etc/yum.repos.d/ICINGA-snapshot.repo