A node agent for measuring, processing and forwarding node level metrics. It is part of the ClusterCockpit ecosystem.
The metric collector sends (and receives) metric in the [InfluxDB line protocol](https://docs.influxdata.com/influxdb/cloud/reference/syntax/line-protocol/) as it provides flexibility while providing a separation between tags (like index columns in relational databases) and fields (like data columns).
There is a single timer loop that triggers all collectors serially, collects the collectors' data and sends the metrics to the sink. This is done as all data is submitted with a single time stamp. The sinks currently use mostly blocking APIs.
The receiver runs as a go routine side-by-side with the timer loop and asynchronously forwards received metrics to the sink.
The `interval` defines how often the metrics should be read and send to the sink. The `duration` tells collectors how long one measurement has to take. This is important for some collectors, like the `likwid` collector.
If you want support for the [Ganglia Monitoring System](http://ganglia.info/), you have to add `-tags ganglia` to the build command line. This enables two metric sinks. One is using the command line application `gmetric` (see [`ganglia`](./sinks/gangliaSink.md) sink), the other one interacts directly with `libganglia` the main Ganglia library that is commonly installed on each compute node (see [`libganglia`](./sinks/libgangliaSink.md) sink). The later one requires configuration before building, so use `make` instead of `go build` directly.
The ClusterCockpit ecosystem is designed to be used by different HPC computing centers. Since configurations and setups differ between the centers, the centers likely have to put some work into the cc-metric-collector to gather all desired metrics.
