ZFS to InfluxDB Monitoring Script for TrueNas

reportZFS.py

# A python script that can be run on TrueNas without installing any further libs.
# This script send zpool iostat to an InfluxDB 2.
# Use this script if you want to avoid creating jails.
#
# Run on start with crontab (and avid sending emails on output): 
#   MAILTO=""
#   @reboot /usr/local/bin/python /root/reportZFS.py &

import subprocess
import requests

# InfluxDB configuration
influx_url = "http://influx:8068"
influx_token = ""
influx_org = ""
influx_bucket = ""
influx_measurement = "zfs_stats"

# name of the zfs pool
pool_name = ""

# ZFS command to get statistics, poll rate 1sec
zfs_command = ["zpool", "iostat", "-y", "-p", "-H", pool_name, "1"]

def monitor_zfs_iostat(command):
    try:
        with subprocess.Popen(command, stdout=subprocess.PIPE, stderr=subprocess.PIPE, text=True) as proc:
            for output in proc.stdout:
                
                if output == '' and proc.poll() is not None:
                    break
                
                lines = output.strip().split('\n')
                headers = ["pool", "alloc", "free", "reads", "writes", "read", "write"]
                data = lines[0].split()
                
                #only send stats when some IO is happening
                if data[3] != '0' or data[4] != '0' :
                    # Create a dictionary with headers as keys and data as values
                    zfs_stats = dict(zip(headers, data))
                    # print(zfs_stats)
                    write_to_influxdb(zfs_stats)

            proc.wait()
            return proc.returncode
    except Exception as e:
        print(f"An error occurred: {e}")
        return 1
    

def write_to_influxdb(stats):
    # Format the data into InfluxDB line protocol
    tags = f"pool={stats.get('pool')}"

    fields = {
        "alloc": int(stats.get("alloc")),
        "free": int(stats.get("free")),
        "read_ops": int(stats.get("reads")),
        "write_ops": int(stats.get("writes")),
        "read_bytes": int(stats.get("read")),
        "write_bytes": int(stats.get("write")),
    }

    data = f"{influx_measurement},{tags} " + ",".join([f"{k}={v}" for k, v in fields.items()]) 

    # Send the data to InfluxDB
    url = f"{influx_url}/api/v2/write?org={influx_org}&bucket={influx_bucket}&precision=s"
    headers = {
        "Authorization": f"Token {influx_token}",
        "Content-Type": "application/octet-stream",
    }

    response = requests.post(url, headers=headers, data=data)

    if response.status_code != 204:
        print(f"Error writing to InfluxDB. Status Code: {response.status_code}, Response: {response.text}")

if __name__ == "__main__":
   
    return_code = monitor_zfs_iostat(zfs_command)
    
    print(f"Subprocess finished with return code: {return_code}")