title: Hpa not fetching existing custom metric?
body: <p>I'm using <code>mongodb-exporter</code> for store/query the metrics via <code>prometheus</code>. I have set up a custom metric server and storing values for that . </p>
  
  <p>That is the evidence of <code>prometheus-exporter</code> and <code>custom-metric-server</code> works compatible .</p>
  
  <p><strong>Query:</strong></p>
  
  <pre><code>kubectl get --raw "/apis/custom.metrics.k8s.io/v1beta1/namespaces/monitoring/pods/*/mongodb_mongod_wiredtiger_cache_bytes"
  </code></pre>
  
  <p><strong>Result:</strong></p>
  
  <pre><code>{"kind":"MetricValueList","apiVersion":"custom.metrics.k8s.io/v1beta1","metadata":{"selfLink":"/apis/custom.metrics.k8s.io/v1beta1/namespaces/monitoring/pods/%2A/mongodb_mongod_wiredtiger_cache_bytes"},"items":[{"describedObject":{"kind":"Pod","namespace":"monitoring","name":"mongo-exporter-2-prometheus-mongodb-exporter-68f95fd65d-dvptr","apiVersion":"/v1"},"metricName":"mongodb_mongod_wiredtiger_cache_bytes","timestamp":"TTTTT","value":"0"}]}
  </code></pre>
  
  <p>In my case when I create a hpa for this custom metrics from mongo exporter, hpa return this error to me :</p>
  
  <pre><code>failed to get mongodb_mongod_wiredtiger_cache_bytes utilization: unable to get metrics for resource mongodb_mongod_wiredtiger_cache_bytes: no metrics returned from resource metrics API
  </code></pre>
  
  <p>What is the main issue on my case ? I have checked all configs and flow is looking fine, but where is the my mistake .</p>
  
  <p>Help </p>
  
  <p>Thanks :) </p>