Sending emails on Proxmox via CLI on tomleb's blog

I want to be able to send emails from my Proxmox node to notify me when my UPS is on battery.

If you already have an SMTP notification target set as the default notification mechanism, you can go straight to Sending an email.

Configuring SMTP notifications

First, we must configure an SMTP notification target and make it the default Notification matcher. Follow the steps below or alternatively take a look at the official Proxmox Notifications documentation.

Find the Notifications tab by going to Datacenter and then Notifications.

Proxmox Notification tab

Next, add a new notification target by clicking Add and filling the form. The values depends on your email provider, so it is likely to differ from mine.

Proxmox SMTP form

You can test this notification target by selecting it in the notification tab and clicking on the *Test button.

Finally, change the notification matcher default-matcher to use this new SMTP target. To do this, select the notification matcher from the notifications tab, click on Modify and go to the Targets to notify tab.

Proxmox Notification Matcher form

That’s it, future notifications from Proxmox should now be sent to your configured email address.

Sending an email

To send an email from the CLI, you can pipe an email message to /usr/bin/proxmox-mail-forward command1. This will find the matcher and notification target that we configured earlier - by reading from /etc/pve/notifications.cfg and /etc/pve/priv/notifications.cfg - and will read the email from stdin and send it to the target.

The email in stdin must follow this format:

Subject: <title>

<body>

Here’s a simple one liner:

printf 'Subject: Testing\n\nTesting an email with Proxmox\n' | proxmox-mail-forward

Or using a heredoc:

cat <<EOF | proxmox-mail-forward
Subject: UPS $UPSNAME update: $NOTIFYTYPE

Here are more information from that UPS:

$(upsc $UPSNAME)
EOF

  1. The source code of proxmox-mail-forward can be found here. It would be nice if we had a bit more control over which matcher to use so that we don’t need to make this the default matcher. It would also be nice if it would work with all the supported notification types (eg: ntfy.sh, gotify, slack, etc) ↩︎

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