Introduction

This module provides a configuration driven random metric generator for Prometheus. It can be configured by means of a configuration file in the ixortalk config server to generate metric values based on different value generators. The faker can be configured at runtime and will also create corresponding assets in assetmgmt to act as dummy assets. These dummy assets can then feed data into prometheus.

Value Generators

The faker supports a number of value generators that can be attached to Prometheus metrics.

• ConstantValueGenerator (generates a constract value for the given metric)
• SinWaveValueGenerator (generates a sin wave value for the given metric)
• RandomValueGenerator (generates a random value for the given metric)

Configuration

A typical configuration file looks like this :

{
  "metrics": {
    "gauge_constant": {
      "enabled": true,
      "type": "ConstantValueGenerator",
      "props": {
        "interval": 1,
        "constantValue": 10
      }
    },
    "gauge_sinwave": {
      "enabled": true,
      "type": "SinWaveValueGenerator",
      "props": {
        "interval": 1
      }
    },
    "gauge_random": {
      "enabled": true,
      "type": "RandomValueGenerator",
      "props": {
        "from": 1,
        "to": 100
      }
    }
  }
}

and is stored in the ixortalk.config.server project in the ixortalk.prometheus.faker folder.

IxorTalk integration

Docker compose

You can add the fakers to your stack by using docker compose. By specifying a hostname, we can ensure that the fakers can be called by that name, as

  prometheus-faker1:
    image: ixortalk/ixortalk.prometheus.faker:${IXORTALK_PROMETHEUS_FAKER_VERSION:-latest}
    hostname: prometheus-faker1
    depends_on:
      ixortalk-config-server:
        condition: service_healthy

  prometheus-faker2:
    image: ixortalk/ixortalk.prometheus.faker:${IXORTALK_PROMETHEUS_FAKER_VERSION:-latest}
    hostname: prometheus-faker2
    depends_on:
      ixortalk-config-server:
        condition: service_healthy

Container startup - asset creation

Upon starting, the container will create an asset in asset management (if one does not exist) using the following properties.

{
    "assetId": "0494a790-51f7-4528-a113-654735d4a24d",
    "assetProperties": {
        "properties": {
            "assetId": "prometheus-faker1",
            "hostname": "prometheus-faker1",
            "port": 9191
        }
    },
    "children": [],
    "roles": [],
    "_links": {
        "self": {
            "href": "http://localhost:8888/assetmgmt/assets/0494a790-51f7-4528-a113-654735d4a24d"
        },
        "asset": {
            "href": "http://localhost:8888/assetmgmt/assets/0494a790-51f7-4528-a113-654735d4a24d"
        }
    }
}

Asset Management

These assets can also be found in the Assetmgmt ui application

And its details can be found at

Grafana

2 Grafana dashboards are also provided

Grafana overview

The grafana overview dashboard shows you the different assets and give an indication of their uptime :

Stopping one of the fakers

docker-compose stop prometheus-faker2
Stopping demo_prometheus-faker2_1 ... done

Will result in one of the assets becoming red, as it is no longer being detected prometheus

From the overview dashboard we can also see its details, showing the individual metrics

Prometheus endpoint

When started, a prometheus endpoint will be made available at http://prometheus-faker1:9191/prometheus

Updating the configuration

You can update runtime configuration by POSTing to the /updateconfig/gauge_constant like this :

curl -v -X POST -H "Content-Type: application/json" -d '{"enabled": true,"type": "ConstantValueGenerator","metric_name": "gauge_constant","props": {"interval": 1,"constantValue": 2}}' http://prometheus-faker1:9191/updateconfig
curl -v -X POST -H "Content-Type: application/json" -d '{"enabled": true,"type": "SinWaveValueGenerator","metric_name": "gauge_sinwave","props": {"interval": 5}}' http://prometheus-faker1:9191/updateconfig/gauge_sinwave
curl -v -X POST -H "Content-Type: application/json" -d '{"enabled": true,"type": "RandomValueGenerator","metric_name": "gauge_random","props": {"from": 200, "to":400}}' http://prometheus-faker1:9191/updateconfig/gauge_random

But be aware that this won't persist the configuration. So on next startup it will again read the configuration from the config server.