Prometheus RemoteWrite Plugin

The Prometheus RemoteWrite plugin enables Meridian to persist time series performance and latency data to any Prometheus remote-write compatible time series store (for example, VictoriaMetrics, Mimir, or Cortex). The plugin uses the time series storage integration layer to convert metrics to a Prometheus model and delegate writes and reads to the configured time series store. It also lets you visualize graphs from the time series store in the OpenNMS plugin for Grafana through the OpenNMS performance data source or the Prometheus data source.

Figure 1. Prometheus RemoteWrite plugin architecture

Requirements

You must have the following before you start to use the Prometheus RemoteWrite plugin:

A Prometheus remote-write compatible time series store, such as VictoriaMetrics, Mimir, or Cortex 1.10.0+

Deployment

To use the Prometheus RemoteWrite plugin, follow these steps:

Start your Prometheus remote-write compatible time series store (see the VictoriaMetrics documentation, Mimir documentation, or Cortex documentation for instructions). If your aim is to get up to speed quickly in a test environment, you can use Docker Compose to deploy a minimal, standalone Cortex node.
Download the plugin’s .kar file from GitHub.
Copy the .kar file into ${OPENNMS_HOME}/deploy.

Enable and configure time series database plugins in ${OPENNMS_HOME}/etc/opennms.properties.d/timeseries.properties:

org.opennms.timeseries.strategy=integration (1) (2)
org.opennms.timeseries.tin.metatags.tag.node=${node:label} (3)
org.opennms.timeseries.tin.metatags.tag.location=${node:location}
org.opennms.timeseries.tin.metatags.tag.geohash=${node:geohash}
org.opennms.timeseries.tin.metatags.tag.ifDescr=${interface:if-description}
org.opennms.timeseries.tin.metatags.tag.ifName=${interface:if-name}

1	Make sure that the `org.opennms.timeseries.strategy` property is set only once so you don’t have conflicting values in multiple `properties` files.
2	If you are enabling the dual write plugin on an existing installation and want to keep historical metrics, do not set the `org.opennms.timeseries.strategy` to `integration` until you have written enough data to expire any collected data prior to enabling the dual write feature.
3	See the time series integration section for more information on defining metatags.

If you are deploying to a container, instead of setting org.opennms.timeseries.strategy via a properties file, you can set your container’s environment variables configuration to specify OPENNMS_TIMESERIES_STRATEGY=integration.

Configure the Prometheus RemoteWrite plugin in Meridian via the Karaf shell, or by creating or modifying ${OPENNMS_HOME}/etc/org.opennms.plugins.tss.prometheus.cfg.

The writeUrl and readUrl properties are required. All other properties shown here are example values to overwrite the defaults. Monitor your time series store’s performance and adjust these properties as necessary. Substitute the correct host and port for your time series store.

Karaf shell
CFG file

Configure the plugin’s properties:

config:edit org.opennms.plugins.tss.prometheus
property-set writeUrl http://victoriametrics-host:8428/api/v1/write
property-set readUrl http://victoriametrics-host:8428/prometheus/api/v1
property-set maxConcurrentHttpConnections 100
property-set writeTimeoutInMs 1000
property-set readTimeoutInMs 1000
property-set metricCacheSize 1000
property-set externalTagsCacheSize 1000
property-set bulkheadMaxWaitDurationInMs 9223372036854775807
config:update

Create or modify the ${OPENNMS_HOME}/etc/org.opennms.plugins.tss.prometheus.cfg file:

writeUrl=http://victoriametrics-host:8428/api/v1/write
readUrl=http://victoriametrics-host:8428/prometheus/api/v1
maxConcurrentHttpConnections=100
writeTimeoutInMs=1000
readTimeoutInMs=1000
metricCacheSize=1000
externalTagsCacheSize=1000
bulkheadMaxWaitDurationInMs=9223372036854775807

The URL paths shown above are for VictoriaMetrics single-node. For Cortex, use writeUrl=http://cortex-host:9009/api/prom/push and readUrl=http://cortex-host:9009/prometheus/api/v1. For Mimir, follow the Mimir documentation for its remote-write endpoint.

Edit or create ${OPENNMS_HOME}/etc/featuresBoot.d/prometheus-remotewrite.boot to configure the plugin to remain installed after Meridian restarts:
```
opennms-plugins-prometheus-remotewrite wait-for-kar=opennms-prometheus-remotewrite-plugin
```
Restart the Meridian service.

Validation

After the first collection cycle (five minutes by default), query the time series store to confirm that metrics are arriving:

curl -s 'http://victoriametrics-host:8428/api/v1/series' \
  --data-urlencode 'match[]={resourceId!=""}' \
  --data-urlencode 'start=0' | jq '.data | length'

A non-zero result confirms the plugin is writing successfully. If the count is 0, check ${OPENNMS_HOME}/logs/karaf.log for errors (filter for cortex, prometheus, or tss).

Time series store tips

VictoriaMetrics

VictoriaMetrics ships with a built-in PromQL query UI at http://victoriametrics-host:8428/vmui. The cardinality explorer at http://victoriametrics-host:8428/vmui/?#/cardinality lists labels and series counts.

Cortex

When using Cortex as the time series store, navigate to the following URLs to view information about your Cortex server:

Server status: http://cortex-host:9009
Ring: http://cortex-host:9009/ring
Internal metrics: http://cortex-host:9009/metrics