Docs: Rename nginx-ingress-controller-app to ingress-nginx.

[Gacko]

This PR:

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Checklist

• Added a CHANGELOG entry

Testing

The instance of external-dns installed as part of Giant Swarm platform releases watches services in the kube-system namespace with annotations giantswarm.io/external-dns=managed and external-dns.alpha.kubernetes.io/hostname matching the clusters base domain. (You can find this in the deployments args --domain-filter value)

You can take this example Service, apply it to your cluster. Change the external-dns.alpha.kubernetes.io/hostname annotation to match your clusters base domain.

then:

• Check external-dns logs for lines like Desired change: CREATE test.your.configured.domain.gigantic.io CNAME
• Try to resolve the domain (https://www.dnstester.net/)

apiVersion: v1
kind: Service
metadata:
  annotations:
    external-dns.alpha.kubernetes.io/hostname: test.your.configured.domain.gigantic.io
    external-dns.alpha.kubernetes.io/ttl: "60"
    giantswarm.io/external-dns: managed
  name: test-external-dns
  namespace: kube-system
spec:
  type: ExternalName
  externalName: www.giantswarm.io

For testing upgrades:

• Create the service and check for creation
• Upgrade
• Delete the service and check for deletion

Default app on AWS releases

• Fresh install works
• Upgrade works

Default app on Azure releases

• Fresh install works
• Upgrade works

Optional app (KVM)

• Fresh install works
• Upgrade works