custom_metrics_hpa.md

Enabling custom metrics HPA for starboard-exporter

Required components

Prometheus Adapter

Steps

1. Install prometheus adapter.

   1. Configure helm chart to connect with prometheus to get the metrics. Change the values as required.

      prometheus:
        # Value is templated
        url: http://prometheus-operated.monitoring.svc
        port: 9090
        path: ""
      

   2. Create seriesQuery & metricsQuery to fetch metrics for the required components. For example, labels like app="starboard-exporter" or job="starboard-exporter" can be used to filter the starboard-exporter metrics in prometheus. Change the values as required.

       rules:
         custom:
           - seriesQuery: 'scrape_duration_seconds{job="starboard-exporter"}'
             seriesFilters: []
             resources:
               template: <<.Resource>>
             name:
               as: "scrapedurationseconds"
             metricsQuery: scrape_duration_seconds{job="starboard-exporter"}
      

   Make sure prometheus adapter is scraping the metrics & exposing the custom metric

   export TEST_NAMESPACE=giantswarm
   kubectl get --raw "/apis/custom.metrics.k8s.io/v1beta1/namespaces/$TEST_NAMESPACE/pods/*/scrapedurationseconds" 
   kubectl get --raw "/apis/custom.metrics.k8s.io/v1beta1/namespaces/$TEST_NAMESPACE/services/*/scrapedurationseconds" | jq -r .

2. Enable customMetricsHPA from values.yaml