For each of the available integrations, Alertmanager already includes built-in templates for their notifications. However, these can be tailored to the specific needs of the user and/or organization. Similar to the alerting rule annotations we explored in Chapter 9, Defining Alerting and Recording Rules, alert notifications are templated using the Go templating language. Let's use the Slack integration as an example and understand how the messages are constructed so that they are tailored to your needs.
Customizing your alert notifications
Default message format
To have an idea of what a notification without any customization looks like, we're going to use a very simple example. Take the following alerting rule,...