The current version in portage net-analyzer/prometheus-2.0.0_beta1 has a known random crash bug; not very good for a monitoring system. beta2 seems to work stably. Reusing the beta1 ebuild with no changes is sufficient.
can you provide a link for that? (like the upstream bug ticket...)
Upstream bug is https://github.com/prometheus/prometheus/issues/3064
commit eb9211408a13f3f7fcc0aca0331836fbfdea093c Author: Manuel Rüger <mrueg@gentoo.org> Date: Sun Sep 10 13:54:59 2017 +0200 net-analyzer/prometheus: Version bump to 2.0.0_beta2 Package-Manager: Portage-2.3.8, Repoman-2.3.3