fail2ban

Fail2Ban Monitoring Template with Telegraf

Dashboards

Fail2Ban

InfluxDB UI

In the InfluxDB UI, go to Settings->Templates and enter this URL: https://raw.githubusercontent.com/influxdata/community-templates/master/fail2ban/img/fail2ban-template.yml

Setup Instructions

If you have your InfluxDB credentials configured in the CLI, you can install this template with:

influx apply -f https://raw.githubusercontent.com/influxdata/community-templates/master/fail2ban/fail2ban-template.yml

Once installed, you'll need to start up Telegraf to pull metrics from your Fail2Ban client. Checkout Telegraf docs for installing and starting Telegraf.

Telegraf Configuration requires the following environment variables:

• INFLUX_ORG
• INFLUX_TOKEN
• INFLUX_HOST
• INFLUX_BUCKET

To start Telegraf with the template-provided configuration follow setup instructions:

Setup Fail2Ban

You can use Fail2Ban that is packed in your favorite Linux Distribution. On Debian based distributions you can use apt install fail2ban.

Telegraf uses fail2ban-client commandline tool to read metrics. Telegraf needs to have a permission to access /var/run/fail2ban/fail2ban.sock to execute fail2ban-client.

To check this try run fail2ban-client status under telegraf user account. If you see:

fail2ban-client status
Permission denied to socket: /var/run/fail2ban/fail2ban.sock, (you must be root)

You can fix socket permission issue like this:

Add new group fail2ban

root@debian:~$ addgroup --group fail2ban

Add user telegraf to fail2ban group

root@debian:~$ usermod -a -G fail2ban telegraf

Set permissions

root@server:~$ chown root:fail2ban /var/run/fail2ban/fail2ban.sock
root@server:~$ chmod g+rwx /var/run/fail2ban/fail2ban.sock

Now you can run fail2ban-client status again, and you should see:

rob@server:~$ fail2ban-client status
Status
|- Number of jail:	1
`- Jail list:	sshd

Note that this permission fix can be reset by systemd.

Systemd fail2ban.service settings

To make permissions permanent you can append them into systemd /lib/systemd/system/fail2ban.service configuration:

[Service]
...
ExecStartPost=/bin/sh -c "while ! [ -S /run/fail2ban/fail2ban.sock ]; do sleep 1; done"
ExecStartPost=/bin/chgrp fail2ban /run/fail2ban/fail2ban.sock
ExecStartPost=/bin/chmod g+w /run/fail2ban/fail2ban.sock

Then restart the service:

root@server:~$ systemctl restart fail2ban.service

Included resources

• 1 label: fail2ban
• 1 Dashboard: Fail2Ban Metrics
• 3 Variables: bucket, host, jail
• 1 Telegraf Configuration:
  • [[inputs.fail2ban]] - https://github.com/influxdata/telegraf/tree/master/plugins/inputs/fail2ban
  • basic system metrics from [[inputs.cpu]], [[inputs.system]], [[inputs.kernel]], [[inputs.mem]], [[inputs.net]], [[inputs.processes]],[[inputs.disk]], [[inputs.diskio]] plugins

Measurements

fail2ban

• Tags
  • host
  • jail
• Fields
  • failed
  • banned

Contact

Author: Robert Hájek

Email: [email protected]

Github: rhajek

Influx Slack: @robert.hajek