Prometheus + Alertmanager

No, Prometheus combined with Alertmanager acts purely as a detection and notification layer; it does not automatically restart processes by itself. While Prometheus scrapes metrics from your targets, Alertmanager handles the routing and silencing of alerts via email, Slack, or PagerDuty. To automatically restart processes, you would need to integrate it with an executor like Kubernetes or a custom webhook script.

You can route alerts to specific Slack channels by configuring the `routes` and `receivers` sections in your `alertmanager.yml` configuration file. By using matchers based on labels like `severity` or `team`, you can send critical alerts to an on-call PagerDuty account and warnings to a general Slack channel. You must restart the Alertmanager service for the new YAML configuration to take effect.

Prometheus is the time-series database that actively scrapes and stores metrics from your application endpoints, while Alertmanager is a standalone tool that handles the deduplication, grouping, and routing of alerts. Prometheus evaluates rule files and pushes fired alerts to Alertmanager over a specified HTTP port. Alertmanager then takes those alerts and distributes them to your chosen notification integrations.

You can easily test Alertmanager routing by using the `amtool` command-line utility, which allows you to inject test alerts directly into your Alertmanager instance. Alternatively, you can temporarily set an alert's severity label to `test` in your Prometheus rules and observe the routing. This ensures that your complex notification trees are correctly configured before a real outage occurs.