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After installing Telegraf and hooking up everything into InfluxDB, I was missing the status of my backups. Every system here creates encrypted backups every night, and stores them on a central NAS, and off-site. But I want to know statistics about the backups, and see if something is not working.

I'm using Restic for the backups (will blog about this another time). However Telegraf does not support Restic directly, I need a few workarounds. This blog post however is not directly about monitoring the backups, but about how to write your own plugin for Telegraf.

I have an InfluxDB up and running in my network, and decided to monitor all (well, all possible - the QNAP seems to be a problem) devices. That's quite easy to do by installing Telegraf as a server agent, and add some configuration. Everything is deployed using Ansible, so I can re-use the same Playbook for many devices.

I'm in the process of updating my entire home setup, and integrate everything properly. Part of this process is to automate everything, and use Ansible Playbooks to deploy devices and configurations.

Today: install Telegraf and send data to InfluxDB

Along the way something broke, and Ansible doesn't really like me anymore. But let's start at the beginning.

In the Telegraf configuration in "/etc/telegraf/telegraf.conf" one can specify output plugins. One of them (probably the most used one) is "InfluxDB". The InfluxDB instance(s) are specified as a [...] list. In Ansible I somehow need to have this list as a string, and write it into the configuration file. This happens:

TASK [Update telegraf.conf InfluxDB settings] ***************************************************
changed: [localhost] => (item={'section': '[outputs.influxdb]', 'option': 'urls', 'value': ['http://192.168.xxx.xxx:8086'], 'state': 'present'})
[WARNING]: The value ['http://192.168.xxx.xxx:8086'] (type list) in a string field was converted to "['http://192.168.xxx.xxx:8086']" (type string). If this does not look like what you expect, quote the entire value to ensure it does not change.

Looks nasty ...