For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/devel:languages:python/openSUSE_Tumbleweed/devel:languages:python.repo
zypper refresh
zypper install rrdtool
For openSUSE Factory PowerPC run the following as root:
zypper addrepo https://download.opensuse.org/repositories/devel:languages:python/openSUSE_Factory_PowerPC/devel:languages:python.repo
zypper refresh
zypper install rrdtool
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/devel:languages:python/15.6/devel:languages:python.repo
zypper refresh
zypper install rrdtool