Flagger can be configured to send Slack notifications:

helm upgrade -i flagger flagger/flagger \
--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

Microsoft Teams

Flagger can be configured to send notifications to Microsoft Teams:

helm upgrade -i flagger flagger/flagger \
--set msteams.url=

Flagger will post a message card to MS Teams when a new revision has been detected and if the canary analysis failed or succeeded:

MS Teams Notifications

And you'll get a notification on rollback:

MS Teams 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 }}"

Event Webhook

Flagger can be configured to send event payloads to a specified webhook:

helm upgrade -i flagger flagger/flagger \
--set eventWebhook=

When configured, every action that Flagger takes during a canary deployment will be sent as JSON via an HTTP POST request. The JSON payload has the following schema:

"name": "string (canary name)",
"namespace": "string (canary namespace)",
"phase": "string (canary phase)",
"metadata": {
"eventMessage": "string (canary event message)",
"eventType": "string (canary event type)",
"timestamp": "string (unix timestamp ms)"


"name": "podinfo",
"namespace": "default",
"phase": "Progressing",
"metadata": {
"eventMessage": "New revision detected! Scaling up podinfo.default",
"eventType": "Normal",
"timestamp": "1578607635167"

The event webhook can be overwritten at canary level with:

- name: "send to Slack"
type: event
url: http://event-recevier.notifications/slack