[stable/gocd] add host in template ingress.yaml instead of using default backend

[colachg]

What this PR does / why we need it:

if there is no host in template ingress.yaml, use default backend.

Which issue this PR fixes

(optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged)

• fixes [stable/gocd] GoCD Ingress default template #10750

Special notes for your reviewer:

Checklist

[Place an '[x]' (no spaces) in all applicable fields. Please remove unrelated fields.]

• DCO signed
• Chart Version bumped
• Variables are documented in the README.md

[colachg]

@arvindsv @varshavaradarajan
I have deleted my repo and re-fork the helm/charts, the PR #10795 was closed. So I open this PR.
@sheroy
I take your advice using the default backend if there is no hosts in values.yaml. I have tested in minikube. Maybe you can do me a favor to test this on GKE :).

[sheroy]

@colachg Sure, I'll test it today.

[arvindsv]

@colachg Just for the record, this is different from my recommendation mentioned here. The difference being that it's not backwards compatible with what exists today.

In case you have an ingress host name defined, you can't reach the server through the ingress IP any more. The Default Backend mentioned in the k8s docs will not be used (since one won't be defined, after this change).

I'm not saying that's necessarily wrong. Maybe that is how it is used and you should be expected to only use ingress hosts. I just don't know what it is that people use.

What I like, though, is that with no change made to values.yaml (assuming you had no hosts defined), then the behavior is unchanged and the default backend is still defined and usable.

[arvindsv]

Maybe @MPV, @balboah and others who've contributed to this chart have thoughts / ideas?

[colachg]

@arvindsv Thanks for your time :)

What I like, though, is that with no change made to values.yaml (assuming you had no hosts defined), then the behavior is unchanged and the default backend is still defined and usable.

Yes, the hosts in values are commented out, So the default backend works.
Then if somebody uncomments the hosts (s)he should know what will happen, maybe we can add some explains in comments.

[MPV]

Sorry @arvindsv, we have only spun up mainly agents with this chart so far. Soon looking to migrate our server into Kube too, but I'm not sure I have much input here yet.

Also, I only see the exact change described in this PR, and not much context on why this is needed.

[varshavaradarajan]

@MPV - more context: #10750 and #10795 if you're interested.

[MPV]

To me, the change makes sense in a general sense (supporting Traefik).

I can't speak to the regard how others use the ingress (by IP/hostname) though, sorry.

[arvindsv]

@MPV No worries. Thanks for taking a look and thinking about it.

[arvindsv]

/ok-to-test

[arvindsv]

/approve

[arvindsv]

/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: arvindsv, colachg

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• stable/gocd/OWNERS [arvindsv]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment