Prometheus' Alertmanager (https://prometheus.io/docs/alerting/alertmanager/) is a tool that is especially designed for bigger infrastructures. Pager and alerting programs have been around for a long time, but this one and Prometheus itself are highly optimized for working in a scaling infrastructure. It is also available as a Docker container: https://hub.docker.com/r/prom/alertmanager/.
As we saw in the infrastructure diagram at the beginning of this chapter, we use a separate Prometheus and Alertmanager containers to demonstrate our Runner metrics collection.
The Alertmanager container has a configuration file (srv/prometheus/alertmanager.yml):
global: # The smarthost and SMTP sender used for mail notifications. smtp_smarthost: ...
