cc-metric-collector/sinks/libgangliaSink.md

libganglia sink

The libganglia sink interacts directly with the library of the Ganglia Monitoring System to submit the metrics. Consequently, it needs to be installed on all nodes. But this is commonly the case if you want to use Ganglia, because it requires at least a node daemon (gmond or ganglia-monitor) to work.

The libganglia sink has probably less overhead compared to the ganglia sink because it does not require any process generation but initializes the environment and UDP connections only once.

Configuration structure

{
  "<name>": {
    "type": "libganglia",
    "gmetric_config" : "/path/to/gmetric/config",
    "cluster_name": "MyCluster",
    "add_ganglia_group" : true,
    "add_type_to_name": true,
    "add_units" : true
  }
}

• type: makes the sink an libganglia sink
• meta_as_tags: print all meta information as tags in the output (optional)
• gmond_config: Path to the Ganglia configuration file gmond.conf (default: /etc/ganglia/gmond.conf)
• cluster_name: Set a cluster name for the metric. If not set, it is taken from gmond_config
• add_ganglia_group: Add a Ganglia metric group based on meta information. Some old versions of gmetric do not support the --group option
• add_type_to_name: Ganglia commonly uses only node-level metrics but with cc-metric-collector, there are metrics for cpus, memory domains, CPU sockets and the whole node. In order to get eeng, this option prefixes the metric name with <type><type-id>_ or device_ depending on the metric tags and meta information. For metrics of the whole node type=node, no prefix is added
• add_units: Add metric value unit if there is a unit entry in the metric tags or meta information

Ganglia Installation

My development system is Ubuntu 20.04. To install the required libraries with apt:

$ sudo apt install libganglia1

The libganglia.so gets installed in /usr/lib. The Ganglia headers libganglia1-dev are not required.

I added a Makefile in the sinks subfolder that searches for the library in /usr and creates a symlink (sinks/libganglia.so) for running/building the cc-metric-collector. So just type make before running/building in the main folder or the sinks subfolder.