Fix alertmanager config path in docker compose

[louishhy]

Summary

Fix alertmanager config path in docker compose so it reads the configuration file from docker/alertmanager.yml.

Currently the alertmanager service in docker-compose.yml mounts ./docker to /etc/prometheus.

However, the alertmanager service runs with

--config.file=/etc/alertmanager/alertmanager.yml

which reads the default config inside the image and hence ignoring the promgen webhook receiver.

Verification

Before the fix:

docker compose up -d
docker compose exec alertmanager sh
cat /etc/alertmanager/alertmanager.yml

will return the default config

route:
  group_by: ['alertname']
  group_wait: 30s
  group_interval: 5m
  repeat_interval: 1h
  receiver: 'web.hook'
receivers:
  - name: 'web.hook'
    webhook_configs:
      - url: 'http://127.0.0.1:5001/'
inhibit_rules:
  - source_matchers: [severity="critical"]
    target_matchers: [severity="warning"]
    # Apply inhibition if the alertname is the same.
    # CAUTION:
    #   If all label names listed in `equal` are missing
    #   from both the source and target alerts,
    #   the inhibition rule will apply!
    equal: [alertname, dev, instance]

instead of the config in docker/alertmanager.yml:

receivers:
- name: "default"
  webhook_configs:
  - url: http://web:8000/api/v1/alerts

Fix

Update the docker-compose.yml to correctly mount ./docker/alertmanager.yml to /etc/alertmanager/alertmanager.yml.

[CLAassistant]

All committers have signed the CLA.

[vincent-olivert-riera]

Looks good to me 👍