This configuration will send an alert once in a minute and if alertmanager stops working amixr will detect that it doesn't work and notify you about that.
That expression will always return true. Here is an alert that leverages the previous expression to create a heartbeat alert
groups:
- name: meta
rules:
- alert: heartbeat
expr: vector(1)
labels:
severity: none
annotations:
description: This is heartbeat alert
summary: Alerting Amixr
...
route:
...
routes:
- match:
alertname: heartbeat
receiver: 'amixr-heartbeat'
group_wait: 0s
group_interval: 1m
repeat_interval: 50s
receivers:
- name: 'amixr-heartbeat'
webhook_configs:
- url: {{ heartbeat_url }}
send_resolved: false