A prometheus exporter for fail2ban listerning on :8089, to get the metrics, the program will need to run as root, or have sudo permissions for fail2ban-client.
There are two routes
/metrics is the default for prometheus and will return metrics about all known fail2ban jails
/probe/{jail} ie: /probe/sshd will return the metrics for just the named jail, in this example the sshd jail
# HELP fail2ban_current_banned Number of current banned IPs
# TYPE fail2ban_current_banned gauge
fail2ban_current_banned{jail="sshd"} 0
fail2ban_current_banned{jail="traefik-auth"} 0
# HELP fail2ban_current_failed Number of failed attempts
# TYPE fail2ban_current_failed gauge
fail2ban_current_failed{jail="sshd"} 0
fail2ban_current_failed{jail="traefik-auth"} 0
# HELP fail2ban_total_banned Total Number of banned IPs
# TYPE fail2ban_total_banned gauge
fail2ban_total_banned{jail="sshd"} 0
fail2ban_total_banned{jail="traefik-auth"} 0
# HELP fail2ban_total_failed Total Number of failed attempts
# TYPE fail2ban_total_failed gauge
fail2ban_total_failed{jail="sshd"} 0
fail2ban_total_failed{jail="traefik-auth"} 0
# HELP fail2ban_current_banned Number of current banned IPs
# TYPE fail2ban_current_banned gauge
fail2ban_current_banned{jail="sshd"} 0
# HELP fail2ban_current_failed Number of failed attempts
# TYPE fail2ban_current_failed gauge
fail2ban_current_failed{jail="sshd"} 0
# HELP fail2ban_total_banned Total Number of banned IPs
# TYPE fail2ban_total_banned gauge
fail2ban_total_banned{jail="sshd"} 0
# HELP fail2ban_total_failed Total Number of failed attempts
# TYPE fail2ban_total_failed gauge
fail2ban_total_failed{jail="sshd"} 0
This code is currently work in progress and should not be considered production ready, the service is listerning on 0.0.0.0 and will need root permissions, use with care.
This work was inspired by https://github.com/jangrewe/prometheus-fail2ban-exporter but I wanted to have a http server to query rather than using prometheus's file reading.
I am not a programer and am still learning go, there are naturally optimisations to the code that I am happy to accept PRs for.