When disabling TLS for the admin listener the url for the request has a trailing dot

[corang]

What happened?

When disabling TLS for the admin listener the url for the request has a trailing dot. While this may be fine in vanilla kubernetes, it causes a failure when using a service mesh like istio:
job log:

unable to query config schema: request GET http://redpanda-0.redpanda.redpanda.svc.cluster.local.:9644/v1/cluster_config/schema failed: Service Unavailable, body: "upstream connect error or disconnect/reset before headers. reset reason: connection termination"

main redpanda istio sidecar log:

[2024-08-21T19:41:20.561Z] "- - -" 0 NR filter_chain_not_found - "-" 0 0 0 - "-" "-" "-" "-" "-" - - 10.42.0.109:9644 10.42.0.113:60346 - -

What did you expect to happen?

The URL should not have a trailing dot so that service meshes can resolve the endpoint correctly

How can we reproduce it (as minimally and precisely as possible)?. Please include values file.

listeners:
  admin:
    appProtocol: http
    tls:
      enabled: false

monitoring:
  enabled: true
  enableHttp2: false

deploy redpanda with that config on top of istio with istio-injection enabled and mtls set to strict

Anything else we need to know?

This can be worked around with istio via a set of destination rules and service entries.

If there wasn't a trailing dot this would work:

apiVersion: networking.istio.io/v1alpha3
kind: ServiceEntry
metadata:
    name: redpanda-headless
    namespace: redpanda
spec:
  hosts:
  - redpanda-0.redpanda.redpanda.svc.cluster.local
  ports:
  - number: 9644
    name: admin
    protocol: HTTP
  resolution: NONE
  location: MESH_INTERNAL
---
apiVersion: networking.istio.io/v1beta1
kind: DestinationRule
metadata:
  name: redpanda-headless
  namespace: redpanda
spec:
  host: redpanda-0.redpanda.redpanda.svc.cluster.local
  trafficPolicy:
    tls:
      mode: ISTIO_MUTUAL
      sni: redpanda-0.redpanda.redpanda.svc.cluster.local

However since there is we have to add this set as well

apiVersion: networking.istio.io/v1alpha3
kind: ServiceEntry
metadata:
    name: redpanda-headless-dot
    namespace: redpanda
spec:
  hosts:
  - redpanda-0.redpanda.redpanda.svc.cluster.local.
  ports:
  - number: 9644
    name: admin
    protocol: HTTP
  resolution: NONE
  location: MESH_INTERNAL
---
apiVersion: networking.istio.io/v1beta1
kind: DestinationRule
metadata:
  name: redpanda-headless-dot
  namespace: redpanda
spec:
  host: redpanda-0.redpanda.redpanda.svc.cluster.local.
  trafficPolicy:
    tls:
      mode: ISTIO_MUTUAL
      sni: redpanda-0.redpanda.redpanda.svc.cluster.local.

Which are the affected charts?

Redpanda

Chart Version(s)

$ helm -n redpanda list 
NAME                    NAMESPACE       REVISION        UPDATED                                 STATUS          CHART                           APP VERSION
redpanda                redpanda        1               2024-08-21 19:45:48.328080392 +0000 UTC deployed        redpanda-5.9.1                  v24.2.2

Cloud provider

Local k3d cluster

JIRA Link: K8S-326