gmondump

gmondump [-d level] [-g group] [-c cluster] [-h host] [-m] [-n] [-p port] [-t] [-u] [-v] [-V]

-d level
    Set debug verbosity level (0-10, default 0). Higher values show more packet details.

-g group
    Filter and dump only metrics from specified group (e.g., 'load_one').

-c cluster
    Show metrics only from named cluster.

-h host
    Display metrics only from specific hostname or IP.

-m
    Enable multicast listening (joins 239.2.11.71:8649; default unicast).

-n
    Use numeric IP addresses instead of resolving hostnames.

-p port
    UDP port to listen on (default 8649).

-t
    Terse output mode: compact metric list without full XML.

-u
    Dump unknown or unrecognized metrics.

-v
    Increase verbosity in output.

-V
    Print version information and exit.

gmondump is a diagnostic utility from the Ganglia monitoring system, designed to capture, decode, and display XML-formatted metric packets broadcast by gmond daemons over UDP. Ganglia enables scalable cluster and grid monitoring, sending metrics like CPU load, memory usage, and network I/O via multicast (239.2.11.71:8649) or unicast.

gmondump listens on a specified UDP port, filters packets by cluster, host, or metric group, and outputs human-readable metric data. Ideal for debugging transmission issues, verifying data flow between nodes, or inspecting protocol payloads during Ganglia setup. Output shows structured XML with timestamps, slopes (zero/positive/negative), TNs (time now), and DMAX values for each metric.

Common use: Run on a monitoring node to eavesdrop on traffic, helping diagnose why metrics aren't aggregating in gmetad. Supports terse mode for concise views and numeric hostnames to skip DNS lookups.

Requires UDP privileges; multicast needs network IGMP support. High debug levels produce verbose output. Non-root users can bind to ports >1024. No packet capture persistence—use with tcpdump for logging.

Multicast dump: gmondump -m -p 8649
Filter load metrics: gmondump -g load_one -t
Debug host: gmondump -h mynode.example.com -d 3

Metric: load_one (double, 0.45)
Slope: zero
TN: 1234567890
DMAX: 60
Cluster: mycluster
Host: node1

Developed as part of Ganglia (started 2000 at UC Berkeley for SDSC Blue Horizon supercomputer). gmondump included since early versions (~1.0) for protocol debugging. Current in Ganglia 3.7.x; maintained by contributors on GitHub.

gmond(8), gmetric(1), gstat(1), gmetad(8)