Set up notification channels

Notifications work in two steps: a channel says where messages go, and a rule says which events go to which channels. You need the permission settings:write to change them.

Open Notifications in the sidebar.

#1. Add a channel

Press New channel, pick a type and fill in the fields. Passwords, keys and tokens are encrypted in the database and never shown again; leave a secret empty when editing to keep the saved value.

#E-mail (SMTP)

Recipients are set on each rule and report, not on the channel. E-mails go out as plain text plus an HTML version. With a provider such as Gmail or Microsoft 365, use an app password or a dedicated relay account rather than your own password.

#Signed webhook

Each delivery is signed so you can check it came from your server. The request carries x-croustypatch-timestamp and x-croustypatch-signature: sha256=<hex>, the HMAC-SHA256 of "<timestamp>.<raw body>" with your key. Verify over the raw body and reject old timestamps to stop replays. A short example in Python:

import hmac, hashlib, time

def valid(key: bytes, timestamp: str, body: bytes, signature: str) -> bool:
    if abs(time.time() - int(timestamp)) > 300:
        return False
    expected = hmac.new(key, timestamp.encode() + b"." + body, hashlib.sha256).hexdigest()
    return hmac.compare_digest("sha256=" + expected, signature)

#ntfy

On a public server anyone who knows the topic can read it: choose a long, unguessable name, or use your own server with access control.

#Gotify

#2. Test it

Press Send test on the channel. The message is delivered at once, and the error is shown if it fails. For e-mail it asks who to send to; your own address is suggested (set it under My account).

#3. Create a rule

Channels send nothing until a rule uses them. Press New rule:

1. Events: pick what you care about. Critical events are a host quarantined, a host unresponsive after planned downtime, and a host not back after a reboot. High ones are a failed task and a rolled-back patch.
2. Minimum severity: hide the noise, for example High and above.
3. Channels: one or more of the channels you added.
4. Frequency: Immediate, or a daily digest at a chosen UTC hour. A digest only holds the events since the last one, and sends nothing when there were none.
5. Scope: limit to some host groups, or leave empty for every host.
6. Recipients (e-mail only): roles and extra addresses.

Press Send digest now on a digest rule to see what it looks like.

#4. Optional: a regular report

A rule tells you when something happens. A report is a summary of the fleet sent on a daily, weekly or monthly schedule, even when nothing happened. Create one under Notifications > Reports; see Notifications and reports.

#Checking deliveries

History lists every delivery with its status. A failed delivery is retried five times with growing delays. If a report cannot be sent, the report.failed event is raised, so you can have a rule warn you on another channel.

#Troubleshooting