Hephaestus Demo - Metrics Adapter

This Repository contains a demo of Hephaestus Project.

Brief description

This application periodically queries Hephaestus GUI backend about selected metrics and their values.

It then fires rules using Jboss Drools Rule Engine's Java API.

Example rules can be seen in src/main/resources/static/rules.drl.
To get more information about Java metric representation see Hephaestus Translator.

In a given example fulfilling the rule's requirement results in the Execution Service logging message specified in the rule.

Mapping JSON object from Hephaestus GUI to metric object

To see how to map JSON representation to Java object using Spring Boot see PrometheusQueryService

Example rule definition

Below you can see an example rule

/**
 * Logs if filesystem is taken in more than 80% in /tmp
 */
rule "more_than_80_percent_filesystem_taken"
    dialect "mvel"
    when
        avail_bytes_m : VectorMetric(
            name == "node_filesystem_avail_bytes",
            labels["mountpoint"] == "/tmp",
            avail_bytes : value
        )
        size_bytes_m : VectorMetric(
            name == "node_filesystem_size_bytes",
            labels["mountpoint"] == "/tmp",
            size : value
        )
        executor : ExecutionService()
        eval(1 - (avail_bytes / size) > 0.8)
    then
        executor.log("More than 80% of file system taken in \"/tmp\": " + (1 - (avail_bytes / size)) * 100 + "%");
end

This rule fires when:

• VectorMetric with name "node_filesystem_avail_bytes", and label "mountpoint" = "/tmp" was received from Hephaestus GUI back-end
• VectorMetric with name "node_filesystem_size_bytes", and label "mountpoint" = "/tmp" was received from Hephaestus GUI back-end
• (1 - value of 1. metric (referred to as avail_bytes) / value of 2. metric (referred to as size)) is greater than 0.8 Firing this rule results in the executor logging the appropriate message.

Deployment

To deploy the application on Kubernetes Cluster see Hephaestus Deployment.