Flagger can be configured to send Slack notifications:

helm upgrade -i flagger flagger/flagger \
--namespace=istio-system \
--set slack.url= \
--set \
--set slack.user=flagger

Once configured with a Slack incoming webhook, Flagger will post messages when a canary deployment has been initialised, when a new revision has been detected and if the canary analysis failed or succeeded.

Slack Notifications

A canary deployment will be rolled back if the progress deadline exceeded or if the analysis reached the maximum number of failed checks:

Slack Notifications

Prometheus Alert Manager

Besides Slack, you can use Alertmanager to trigger alerts when a canary deployment failed:

- alert: canary_rollback
expr: flagger_canary_status > 1
for: 1m
severity: warning
summary: "Canary failed"
description: "Workload {{ $ }} namespace {{ $labels.namespace }}"