Error while disabling TLS in server, setting secure-port = 0 throws error

[cerberus20]

What happened?:
We are trying to disable TLS on prom-adapter server so that it listens on plaintext http port. We want istio sidecar to manage TLS. But when settting secure-port=0, we get error:

F0124 08:10:49.144671 1 config.go:541] cannot derive external address port without listening on a secure port.

What did you expect to happen?:
We expected that setting secure-port = 0 will disable TLS on prom adapter server. As per documentation,
--secure-port int The port on which to serve HTTPS with authentication and authorization. If 0, don't serve HTTPS at all. (default 443)

Please provide the prometheus-adapter config:

prometheus-adapter config

  - args:
    - --secure-port=0
    - --logtostderr=true
    - --log_dir=/home/sfdc
    - --log_file=adapter.log
    - --prometheus-url=http://localhost:20001
    - --prometheus-verb=POST
    - --metrics-relist-interval=1m
    - --v=20
    - --config=/etc/adapter/config.yaml
    - --metrics-max-age=15m

Please provide the HPA resource used for autoscaling:

HPA yaml

Please provide the HPA status:

Please provide the prometheus-adapter logs with -v=6 around the time the issue happened:

prometheus-adapter logs

│ I0124 08:10:49.144412 1 requestheader_controller.go:244] Loaded a new request header values for RequestHeaderAuthRequestController │ │ F0124 08:10:49.144671 1 config.go:541] cannot derive external address port without listening on a secure port.

Anything else we need to know?:

Environment:

• prometheus-adapter version: 0.10.0
• prometheus version:
• Kubernetes version (use kubectl version): Client -> v1.23.17 Server-> v1.24.17
• Cloud provider or hardware configuration:
• Other info:

[cerberus20]

Hi @dgrisonnet , can you please help here? Thank you

[dgrisonnet]

/triage accepted
/assign

[osca-mwongera]

Hello, I encountered the same issue. I am deploying the registry.k8s.io/prometheus-adapter/prometheus-adapter:v0.11.2 image without TLS certificates on Kubernetes.