User-provided Name tag on subnets get overwritten

[AverageMarcus]

/kind bug

What steps did you take and what happened:

Specify a subnet on an AWSCluster CR that has a Name tag defined. E.g.

apiVersion: infrastructure.cluster.x-k8s.io/v1beta1
kind: AWSCluster
metadata:
  name: example
spec:
  network:
    subnets:
    - availabilityZone: eu-north-1a
      cidrBlock: 10.0.0.0/24
      isPublic: false
      tags:
        Name: example-custom-subnet-name

This Name tag will be instead replaced with one built in code and instead become Name: example-subnet-private-eu-north-1a

What did you expect to happen:

If a Name tag is provided by the user it is what should be used when creating / updating the subnet. If not provided CAPA should default to the current generated format.

Anything else you would like to add:

Block of code building the Name value: https://github.com/giantswarm/cluster-api-provider-aws/blob/70373384dc117ea387d28a8548d49ecc58e7cca0/pkg/cloud/services/network/subnets.go#L426-L441

Block of code overwriting any user-provided Name tag: https://github.com/giantswarm/cluster-api-provider-aws/blob/70373384dc117ea387d28a8548d49ecc58e7cca0/api/v1beta1/tags.go#L198-L200

As far as I can see, that tag isn't used anywhere in the codebase for matching or looking up of subnets. It seem purely for display.

Multiple subnets can end up with the same Name value.

Environment:

• Cluster-api-provider-aws version: >= 1.5
• Kubernetes version: (use kubectl version):
• OS (e.g. from /etc/os-release):

[dlipovetsky]

/triage accepted
/priority important-soon