124 lines
3.7 KiB
Markdown
124 lines
3.7 KiB
Markdown
# Fail2Ban Prometheus Exporter
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Go tool to collect and export metrics on Fail2Ban
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## Table of Contents
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1. How to use
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2. Docker
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1. Volumes
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2. Docker run
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3. Docker compose
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3. CLI usage
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4. Metrics
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## 1. How to use
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Run the exporter by providing it with a fail2ban database to read data from.
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Read access to the database is required.
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Once the exporter is running, metrics are available at `localhost:9191/metrics`.
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The default port is `9191`, but this can be modified with the `-port` flag.
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**Note:** By default fail2ban stores the database file at: `/var/lib/fail2ban/fail2ban.sqlite3`
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**Fail2Ban Jails**
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fail2ban can be configured to process different log files and use different rules for each one.
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These separate configurations are referred to as *jails*.
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For example, fail2ban can be configured to watch the system logs for failed SSH connections and Nextcloud logs for failed logins.
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In this configuration, there will be two jails - one for IPs banned from the SSH logs, and one for IPs banned from the Nextcloud logs.
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This tool exports several metrics *per jail*, meaning that it is possible to track how many IPs are being banned in each jail as well as the overall total.
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This can be useful to track what services are seeing more failed logins.
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## 2. Docker
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An official docker image is available on the Gitlab container registry.
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Use it by pulling the following image:
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```
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registry.gitlab.com/hectorjsmith/fail2ban-prometheus-exporter:latest
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```
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Use the `:latest` tag to get the most up to date code (less stable) or use one of the version tagged images to use a specific release.
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See the [registry page](https://gitlab.com/hectorjsmith/fail2ban-prometheus-exporter/container_registry) for all available tags.
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### 2.1. Volumes
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The docker image is designed to run by mounting the fail2ban sqlite3 database.
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The database should be mounted at: `/app/fail2ban.sqlite3`
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The database can be mounted with read-only permissions.
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### 2.2. Docker run
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Use the following command to run the forwarder as a docker container.
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```
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docker run -d \
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--name "fail2ban-exporter" \
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-v /var/lib/fail2ban/fail2ban.sqlite3:/app/fail2ban.sqlite3:ro \
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-p "9191:9191"
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registry.gitlab.com/hectorjsmith/fail2ban-prometheus-exporter:latest
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```
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### 2.3. Docker compose
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The following is a simple docker-compose file to run the exporter.
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```
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version: "2"
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services:
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exporter:
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image: registry.gitlab.com/hectorjsmith/fail2ban-prometheus-exporter:latest
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volumes:
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- /var/lib/fail2ban/fail2ban.sqlite3:/app/fail2ban.sqlite3:ro
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ports:
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- "9191:9191"
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```
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## 3. CLI usage
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```
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$ fail2ban-prometheus-exporter -h
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-db string
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path to the fail2ban sqlite database
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-port int
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port to use for the metrics server (default 9191)
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-version
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show version info and exit
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```
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## 4. Metrics
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Access exported metrics at `/metrics` (on the provided port).
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**Note:** All metric names include the `fail2ban_` prefix to make sure they are unique and easier to find.
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Exposed metrics:
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* `up` - Returns 1 if the service is up
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* `bad_ips` (per jail)
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* A *bad IP* is defined as an IP that has been banned at least once in the past
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* Bad IPs are counted per jail
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* `banned_ips` (per jail)
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* A *banned IP* is defined as an IP that is currently banned on the firewall
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* Banned IPs are counted per jail
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**Sample**
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```
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# HELP fail2ban_bad_ips Number of bad IPs stored in the database (per jail).
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# TYPE fail2ban_bad_ips gauge
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fail2ban_bad_ips{jail="jail1"} 6
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fail2ban_bad_ips{jail="jail2"} 8
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# HELP fail2ban_banned_ips Number of banned IPs stored in the database (per jail).
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# TYPE fail2ban_banned_ips gauge
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fail2ban_banned_ips{jail="jail1"} 3
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fail2ban_banned_ips{jail="jail2"} 2
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# HELP fail2ban_up Was the last fail2ban query successful.
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# TYPE fail2ban_up gauge
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fail2ban_up 1
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```
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