Monitor your Nextcloud logs for suspicious activities with Grafana Loki
Relatively unknown are Nextcloud's audit logs. If you enable them, the admin has the possibility to check his instance for suspicious activities.
Monitor Seafile libraries with Grafana
Seafile does not issue a quota warning when a library that you do not own fills up. However, this can be retrofitted with the help of Grafana.
How to write icinga2 plugins for Windows (Part 2: Icinga Powershell Framework)
Writing a monitoring plugin for icinga using their Powershell framework
How to write icinga2 plugins for Windows (Part 1: custome Powershell script)
If you know how to write monitoring plugins, you will have a more efficient monitoring of your system.
Regularly check your Nextcloud instance for vulnerabilities
Nextcloud offers a tool at scan.nextcloud.com with which you can check your Nextcloud instance for known vulnerabilities. With the following script, this can also be conveniently brought into icinga2.
Push icinga2 metrics to Graphite
icinga2 is a monitoring environment that does not inherently process metrics in time series.