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Email (SMTP)

SMTP with PLAIN auth. Tested with Fastmail, Gmail (app password), AWS SES. Emails are sent as multipart/alternative (HTML + plain text), with a severity-colored top bar and a metadata table that renders cleanly in Gmail, Apple Mail, and Outlook.

Configure

ConfigMap:

channels:
  email:
    smtp_host: smtp.fastmail.com
    smtp_port: 587
    from: alerts@example.com
    to: [oncall@example.com]
    user_from_secret: SMTP_USER
    pass_from_secret: SMTP_PASS

Secret:

stringData:
  SMTP_USER: alerts@example.com
  SMTP_PASS: hunter2

Gmail with app password

  1. Enable 2-step verification on your Google account.
  2. Create an app password at myaccount.google.com/apppasswords.
  3. Use smtp.gmail.com:587, your Gmail address as from and SMTP_USER, the app password as SMTP_PASS.

AWS SES

smtp_host: email-smtp.us-east-1.amazonaws.com
smtp_port: 587

Use SMTP credentials from SES (not your IAM keys).

Message format

Subject template:

[<cluster>] <prefix> <title>

<prefix> is the severity / state marker:

Severity Prefix Banner color
info [i] blue (#2563eb)
warning [!] orange (#d97706)
critical [!!] red (#dc2626)
resolved (any prior severity) [RESOLVED] green (#10b981)

The HTML body renders a colored banner matching the table above, followed by a metadata grid (cluster, namespace, object, reason, severity, fired-at) and the body text. A plain-text alternative is included so CLI mail clients fall back gracefully.

Headers added

Each email includes:

  • Date, Message-ID
  • List-Id: kpulse-<cluster> <kpulse.<cluster>.local> (use for Gmail filters)
  • Auto-Submitted: auto-generated
  • X-Kpulse-Cluster, X-Kpulse-Monitor, X-Kpulse-Severity, X-Kpulse-State

A Gmail filter like list:kpulse-prod-eks-1 matches every kpulse alert for that cluster. To route resolved messages to a separate label, add a filter on "X-Kpulse-State: resolved" (Gmail's "Has the words" search matches headers verbatim).

Test

kubectl -n kpulse port-forward svc/kpulse 8080:8080 &
curl 'http://localhost:8080/test-channel?name=email'

Helm

helm upgrade kpulse oci://ghcr.io/dnl555/charts/kpulse \
  --reuse-values \
  --set channels.email.enabled=true \
  --set channels.email.smtpHost=smtp.fastmail.com \
  --set channels.email.smtpPort=587 \
  --set channels.email.from=alerts@example.com \
  --set 'channels.email.to={oncall@example.com}' \
  --set-string channels.secrets.SMTP_USER=alerts@example.com \
  --set-string channels.secrets.SMTP_PASS=hunter2