Enabling Ingress leads to 502 Bad Gateway

[necromancerthedark]

Airflow version: 2.9.3
Helm chart version: 1.15.0

I have enabled ingress in airflow using the ingress block present in helm chart values.yaml, and made following changes:

ingress:
  # Enable all ingress resources (deprecated - use ingress.web.enabled and ingress.flower.enabled)
  enabled: ~

  # Configs for the Ingress of the web Service
  web:
    # Enable web ingress resource
    enabled: true

    # Annotations for the web Ingress
    annotations:
      alb.ingress.kubernetes.io/scheme: internet-facing
      alb.ingress.kubernetes.io/target-type: ip
      alb.ingress.kubernetes.io/ssl-redirect: '443'
      alb.ingress.kubernetes.io/listen-ports: '[{"HTTP": 80}, {"HTTPS":443}]'
      alb.ingress.kubernetes.io/ip-address-type: dualstack
      alb.ingress.kubernetes.io/certificate-arn: some-cert
      alb.ingress.kubernetes.io/tags: some-tag
      alb.ingress.kubernetes.io/group.name: some-group
      alb.ingress.kubernetes.io/healthcheck-path: /health

    # The path for the web Ingress
    path: "/"

    # The pathType for the above path (used only with Kubernetes v1.19 and above)
    pathType: "Prefix"

    # The hostname for the web Ingress (Deprecated - renamed to `ingress.web.hosts`)
    host: ""

    # The hostnames or hosts configuration for the web Ingress
    hosts:
      - airflow.company.com
    #   # The hostname for the web Ingress (can be templated)
    # - name: ""
    #   # configs for web Ingress TLS
    #   tls:
    #     # Enable TLS termination for the web Ingress
    #     enabled: false
    #     # the name of a pre-created Secret containing a TLS private key and certificate
    #     secretName: ""

    # The Ingress Class for the web Ingress (used only with Kubernetes v1.19 and above)
    ingressClassName: "alb"

    # configs for web Ingress TLS (Deprecated - renamed to `ingress.web.hosts[*].tls`)
    tls:
      # Enable TLS termination for the web Ingress
      enabled: false
      # the name of a pre-created Secret containing a TLS private key and certificate
      secretName: ""

    # HTTP paths to add to the web Ingress before the default path
    precedingPaths: []

    # Http paths to add to the web Ingress after the default path
    succeedingPaths: []

and I have added the base_url to be same as our hosts

  webserver:
    enable_proxy_fix: 'True'
    base_url: 'https://airflow.company.com'
    # For Airflow 1.10
    rbac: 'True'

• After applying the helm chart, everything is working fine, we are able to access UI via port-forwarding on the svc and the pod as well but whenever we try to access the https://airflow.company.com (after making a record in route53) we are getting 502 bad gateway . We are using AWS ALB as load balancer.
• We are also not able to set gunicorn to work on IPv6, we are trying to set it because our liveness and readiness probes are failing. We are using IPv6 on our EKS cluster.

[necromancerthedark]

Since I figured it out myself,
I will add the solution here.

adding the --hostname [::] made airflow-webserver to start on http://[::]:8080 instead of http://0.0.0.0:8080, hence solving all our problems at once, the probes started working and TargetGroupBinding's health check passed, hence exposing the application.

I don't know if this is a bug or intended behaviour.