For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:ecsos/openSUSE_Tumbleweed/home:ecsos.repo
zypper refresh
zypper install qemu-guest-agent
For openSUSE Slowroll run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:ecsos/openSUSE_Slowroll/home:ecsos.repo
zypper refresh
zypper install qemu-guest-agent
For 16.0 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:ecsos/16.0/home:ecsos.repo
zypper refresh
zypper install qemu-guest-agent