Overview

ClusterCockpit uses the InfluxData line-protocol for transferring metrics and events between its components. The line-protocol is a text-based representation of a metric/event with a value, time and describing tags. All metrics/events have the following format (if written to stdout):

<measurement>,<tag set> <field set> <timestamp>

where <tag set> and <field set> are comma-separated lists of key=value entries. In a mind-model, think about tags as indices in the database for faster lookup and the <field set> as metric/event values. The <measurement> is here used as "identifier" because it does not represent a "measurement" in all cases.

Line-protocol in the ClusterCockpit ecosystem

In ClusterCockpit we limit the flexibility of the InfluxData line-protocol slightly. The idea is to keep the format evaluatable by different components.

Each metric is identifiable by the measurement (= metric name), the hostname, the type and, if required, a type-id.

Mandatory tags per message:

hostname
type
- node
- socket
- die
- memoryDomain
- llc
- core
- hwthread
- accelerator
type-id for further specifying the type like CPU socket or HW Thread identifier

Although no type-id is required if type=node, it is recommended to send type=node,type-id=0.

Optional tags depending on the message:

In some cases, optional tags are required like filesystem, device or version. While you are free to do that, the ClusterCockpit components in the stack above will recognize stype (= "sub type") and stype-id. So filesystem=/homes should be better specified as stype=filesystem,stype-id=/homes

Mandatory fields per measurement:

The field key is always value. No other field keys are evaluated by the ClusterCockpit ecosystem.

Message types

There exist different message types in the ClusterCockpit ecosystem.

Metrics

Identification: value=X with X being a number

While the measurements (metric names) can be chosen freely, there is a basic set of measurements which should be present as long as you navigate in the ClusterCockpit ecosystem

flops_sp: Single-precision floating point rate in Flops/s
flops_dp: Double-precision floating point rate in Flops/s
flops_any: Combined floating point rate in Flops/s (often (flops_dp * 2) + flops_sp)
cpu_load: The 1m load of the system (see /proc/loadavg)
mem_used: The amount of memory used by applications (see /proc/meminfo)
ipc: instructions-per-cycle metric
mem_bw: Main memory bandwidth (read and write) in MByte/s
cpu_power: Power consumption of the whole CPU package
mem_power: Power consumption of the memory subsystem
clock: CPU clock in MHz
...

For the whole list, see job-data schema

Events

Identification: value="X" with "X" being a string

Controls

Identification: method tag is either GET or PUT