Return unique addresses from service

[hazim1093]

What this PR does / why we need it:

When the ExternalIP of a Service and status.loadBalancer.ingress.ip has the same value, the ingress controller assigns duplicate IPs to the ingress.
This behaviour was noticed while using inlets-operator to provision a VM load balancer for service of type LoadBalancer.

Even though it might be a corner case, I felt it makes sense to assign only unique IPs to the ingress. Having duplicate IPs in the ingress also affects other services which deal with the IPs e.g. external-dns.

Example snippet from service (IP addresses have been changed)

...
spec:
  externalIPs:
  - 10.15.10.15
  externalTrafficPolicy: Cluster
...
  type: LoadBalancer
status:
  loadBalancer:
    ingress:
    - ip: 10.15.10.15

Example snippet of affected ingress

...
spec:
  rules:
  - host: hello.dev.example.com
    http:
      paths:
      - backend:
          serviceName: hello-world
          servicePort: 80
        path: /
        pathType: Prefix
status:
  loadBalancer:
    ingress:
    - ip: 10.15.10.15
    - ip: 10.15.10.15

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

How Has This Been Tested?

I have added a test case for the method returning a unique list.

I also tested the controller by building an image, and running it in a kubernetes environment along side a service with the same values for externalIP and status.loadBalancer.ingress.ip. The controller now only assigns unique IPs to the ingress.

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I've read the CONTRIBUTION guide
• I have added tests to cover my changes.
• All new and existing tests passed.

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[k8s-ci-robot]

Hi @hazim1093. Thanks for your PR.

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[hazim1093]

/assign @bowei

[aledbf]

@hazim1093 thank you for the PR. I would prefer the use of sets.NewString() instead of the suggested change.

[hazim1093]

Hi @aledbf,
Thank you for the suggestion, I have updated the code with sets

[aledbf]

@hazim1093 please squash the commits and this lgtm

[aledbf]

/ok-to-test

[aledbf]

/retest

[aledbf]

/lgtm
/approve

[aledbf]

@hazim1093 thanks!

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: aledbf, hazim1093

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