Duplicati

Beta

Built from Duplicati’s source code and documentation, not yet tested against a real server. Tell us what your server answers differently.

A Duplicati server through its API: the age of each task’s last successful backup, its last result, duration, size, warnings and errors, and the task running now.

Network ports to open

From the DumbMonit server (or its relay agent) to the device:

Port	Protocol	Purpose
8200	TCP	Web interface and API (HTTP, default)

Duplicati has no user accounts, only the password of its web interface. From Duplicati 2.1, DumbMonit exchanges that password for a short-lived access token (POST /api/v1/auth/login, then Authorization: Bearer), keeps it for ten minutes and signs in again if the server refuses it.

Duplicati 2.0

Version 2.0 signs in through /login.cgi (a nonce, a salt and a salted-sha256 hash, then session cookies). That mode is not supported: against a 2.0 server DumbMonit reports that the sign-in route is missing and asks for 2.1 or later.

The task list (GET /api/v1/backups) is the one required read. The others are read when the server answers and never fail the probe:

• GET /api/v1/serverstate: the task running now, and whether the server is paused.
• GET /api/v1/progressstate: the progress of that task.
• GET /api/v1/backup/{id}/log: the result of each task’s last run (Success, Warning, Error, Fatal) with its warning and error counts, for the first 50 tasks. Without it, a failure is deduced from the task’s LastErrorDate and LastErrorMessage.

The task list already carries each task’s metadata (LastBackupDate, LastBackupFinished, LastBackupDuration, LastErrorMessage, sizes), so GET /api/v1/backup/{id} is not called.

What it watches

All metrics are prefixed dumbmonit_duplicati_.

Metric	Labels	Meaning
backup_failed	backup, backup_id	1 when the last run failed: its result is Error or Fatal, or, without the log, an error is more recent than the last run. A warning is not a failure.
backup_running	backup, backup_id	1 for the task running now.
backup_scheduled	backup, backup_id	1 when the task has a schedule.
backup_last_success_age_seconds	backup, backup_id	Since the last successful backup; absent for a task that never succeeded.
backup_last_duration_seconds	backup, backup_id	Duration of the last run.
backup_source_bytes, backup_source_files	backup, backup_id	Size and file count of the source.
backup_target_bytes, backup_versions	backup, backup_id	Size at the destination and number of versions kept.
backup_last_result_info	backup, backup_id, result	Value 1: success, warning, error, fatal.
backup_last_warnings, backup_last_errors	backup, backup_id	Counts of the last run.
backup_last_error_info	backup, backup_id, message	Value 1 with the last error message (200 characters at most), only while the task is failed.
backup_progress_percent	backup, backup_id	Progress of the running task.
server_paused		1 when the server is paused.
backups, backups_failed, backups_running		Counts; at most 200 tasks are described one by one.

The built-in rules that apply:

• Duplicati backup failed (Warning, reminded daily).
• Duplicati backup too old: a scheduled task has not succeeded for more than two days (Advisory, reminded daily).

The monitor page

The Backups panel says what is wrong in a sentence, shows the failed and running counts and whether the server is paused, then lists the tasks — failed first — with the age of their last success, their size and, for a failed one, the last error message.

Let DumbMonit read the Duplicati API

1. In the Duplicati web interface, open Settings and set a long random password for the interface: Duplicati 2.1 requires one.

2. If the server only listens on the machine itself, start it with these options so that DumbMonit can reach it.

   --webservice-interface=any --webservice-allowed-hostnames=*

3. In DumbMonit, enter the Duplicati address (for example nas.lan) and paste that password.

Required permissions

• Interface password — Duplicati has no accounts or read-only mode

Warning

Duplicati 2.1 or later is required: version 2.0 signs in through a different mechanism that DumbMonit does not use. The password gives full access, so keep port 8200 on your local network.

Why these permissions

Duplicati knows a single secret, the interface password; it can neither be limited to reading nor attached to a named account. DumbMonit only issues GET requests apart from the sign-in.

Credentials

Credential	Fields
Web interface password	The password of the Duplicati web interface (stored encrypted).

Address: the host name or IP of the server, host:port, or a URL. Options:

• Protocol (http) and Port (8200).
• Accept an unverifiable certificate: if the server runs over HTTPS with a self-signed certificate.
• Timeout per request (15 s).

Troubleshooting

“Duplicati refused the password”: the password differs from the interface’s.

“this collector needs Duplicati 2.1 or later”: the server has no /api/v1/auth/login; update it.

The server answers “Invalid host header” or a similar refusal: add the name you use in DumbMonit to --webservice-allowed-hostnames.

A task shows no age: it never completed a backup successfully.