Received unsupported Content-Type text/html; charset=utf-8

What

This happens when an exporter does not set the right response content type to json and instead just serves the page as HTML.

This is most notable seen when using intex/xpumanager ⧉

You will see an error such as the below in Prometheus

received unsupported Content-Type "text/html; charset=utf-8"

Solution

We need to set the fallback_scrape_protocol to PrometheusText1.0.0

The documentation details it as

# Fallback protocol to use if a scrape returns blank, unparsable, or otherwise
# invalid Content-Type.
# Supported values (case sensitive): PrometheusProto, OpenMetricsText0.0.1,
# OpenMetricsText1.0.0, PrometheusText0.0.4, PrometheusText1.0.0.
[ fallback_scrape_protocol: <string> ]

monitoring.coreos.com/v1

apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
metadata:
  name: intel-xpumanager
  labels:
    app: intel-xpumanager
spec:
+ fallbackScrapeProtocol: PrometheusText1.0.0
  selector:
    matchLabels:
      app: intel-xpumanager
  endpoints:
    - port: metrics
      path: /metrics
      interval: 5s

Additional Reading

• Fallback scrape config ⧉
• CRD definition ⧉

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