fix(aws): incorrect behavior for non-aliasable record types by u-kai · Pull Request #6017 · kubernetes-sigs/external-dns

u-kai · 2025-12-12T00:05:10Z

What does it do?

This PR fixes incorrect behavior for record types that do not support AWS Alias records (e.g., MX, TXT, SRV, etc.).

Motivation

This work originated from the discussion here:
#5997 (comment)

When a ProviderSpecific property alias=true exists on record types that don't support alias records
(like MX records):

Alias processing continues even after alias property deletion
- The alias property is deleted at aws.go, but the alias variable remains true
- This results in unnecessary evaluateTargetHealth=false being added
TTL value gets unintentionally modified
- When RecordTTL is configured, it gets fixed to 300

Reproduction

ep := &endpoint.Endpoint{
    RecordType: endpoint.RecordTypeMX,
    RecordTTL:  600,
    ProviderSpecific: endpoint.ProviderSpecific{
        {Name: "alias", Value: "true"},
    },
}
// Expected: TTL=600, ProviderSpecific=empty
// But result is: TTL=300, evaluateTargetHealth=false gets added

While this affects cases with incorrectly configured ProviderSpecific properties, I believe the behavior should

More

Yes, this PR title follows Conventional Commits
Yes, I added unit tests
Yes, I updated end user documentation accordingly

Signed-off-by: u-kai <76635578+u-kai@users.noreply.github.com>

k8s-ci-robot · 2025-12-12T00:05:21Z

Hi @u-kai. Thanks for your PR.

I'm waiting for a github.com member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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ivankatliarchuk · 2025-12-12T07:59:04Z

Refactoring and bug fix in single PR. Too risky. As well as for bug, it should be manifests provided to reproduce

u-kai · 2025-12-12T10:47:15Z

@ivankatliarchuk
Sorry about that — I’ll be more careful next time.

To make the existing issue easier to fix, I’ve opened a separate PR with the refactoring work.
Once that PR is merged, I will rebase this PR and continue the bug fix on top of it.

It would be great if you could review the refactoring PR first. Thanks!

into fix/aws-alias-logic

Signed-off-by: u-kai <76635578+u-kai@users.noreply.github.com>

u-kai · 2026-01-28T13:07:32Z

@ivankatliarchuk
Now that the refactoring PR has been merged, I’ve rebased and updated this PR so it’s ready for review again.

ivankatliarchuk · 2026-01-28T20:32:05Z

Missing links to docs in description with facts about this behaviour. Missing end to end tests with the proof.

I'll review only after other reviewers share their review. I could not keep approving on my own.

ivankatliarchuk · 2026-01-28T20:34:20Z

There’s no example showing the current behaviour, so it’s unclear whether this is actually a problem or not.

u-kai · 2026-01-28T22:01:40Z

I’ve updated the PR description.

Previously, even for record types that do not support alias (such as MX records), ExternalDNS was applying alias-specific behavior — updating TTL and adding the evaluateTargetHealth property — whenever alias was set to true.

This was incorrect and also hurt code readability.
With this change, MX records no longer have their TTL modified even if alias is true, and alias-related properties are removed for record types that do not support alias.

ivankatliarchuk · 2026-01-31T08:33:24Z

Missing before and after real example. And missing links to official documentation describing AWS alias record behavior

ivankatliarchuk · 2026-02-07T12:30:46Z

Now:

AWS provider silently “fixes” invalid alias usage
Other providers may not
Behavior diverges across providers

ExternalDNS should enforce provider-agnostic semantics before provider code runs.

ivankatliarchuk · 2026-02-07T12:32:30Z

Ideally, what we should have

Reject invalid combinations at middleware layer:

alias=true only allowed for A / AAAA
fail endpoint validation
surface a clear debug msg

This is the cleanest contract.

u-kai · 2026-02-11T04:40:52Z

Totally agree — the issue here is the responsibility boundary.

To move in that direction, I opened a follow-up PR that makes endpoint validation fail when alias=true is used for non A/AAAA,CNAME record types. Once that PR is merged, this PR can be simplified further.

I’ll update this PR accordingly once the validation change lands.

into fix/aws-alias-logic

Signed-off-by: u-kai <76635578+u-kai@users.noreply.github.com>

ivankatliarchuk · 2026-03-01T19:46:09Z

Is this resolved or still a problem?

u-kai · 2026-03-04T13:12:31Z

Sorry, it has already been resolved.

ivankatliarchuk · 2026-03-31T06:25:05Z

Sorry, it has already been resolved.

/close

k8s-ci-robot · 2026-03-31T06:25:12Z

@ivankatliarchuk: Closed this PR.

Details

In response to this:

Sorry, it has already been resolved.

/close

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u-kai · 2026-03-31T06:29:11Z

Sorry for the confusion. "Resolved" was referring to the code review comment being addressed, not the PR itself being resolved. I'll reopen this.

u-kai · 2026-03-31T06:29:18Z

/reopen

k8s-ci-robot · 2026-03-31T06:29:24Z

@u-kai: Reopened this PR.

Details

In response to this:

/reopen

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ivankatliarchuk · 2026-03-31T06:37:42Z

Ok

ivankatliarchuk

I think the change missing some links in PR title + debug logs or something.

High level. We have a gap - no end 2 end test that stitches together CheckEndpoint → dedupSource → AdjustEndpoints to show the full rejection path. The two unit tests exist, but their composition is not visible in unit tests.

ivankatliarchuk · 2026-03-31T06:58:26Z

Are we cleaning up the providerSpecificAlias property in wrapper layer? This was just added in recent PR https://github.com/kubernetes-sigs/external-dns/pull/6021/changes

I've separated this into the PR below:
#6342

PR has merged! thanks!

ivankatliarchuk · 2026-03-31T07:01:02Z

 			expectedAaaa: nil,
 		},
-		// TODO: fix For records other than A, AAAA, and CNAME, if an alias record is set, the alias record processing is not performed. This will be fixed in another PR.
-		{


I'm not sure. Maybe instead of removing test, actually provide a current code behaviour with changed name?

You're right that this case can still exist from a unit test perspective.
However, in the current design, it's difficult for an alias record to be used with MX, since it's prevented at another layer, so I removed the test.

What kind of test name would you suggest if we keep it?

into fix/aws-alias-logic

Co-authored-by: Ivan Ka <5395690+ivankatliarchuk@users.noreply.github.com>

into fix/aws-alias-logic

…al-dns into fix/aws-alias-logic

u-kai · 2026-04-22T12:27:07Z

The links and before/after examples are already included in the comments above.

Regarding E2E tests:
I agree it would be valuable, but I'd prefer to track it as a follow-up rather than blocking this fix.

ivankatliarchuk · 2026-05-03T10:09:57Z

/lgtm
/approve

k8s-ci-robot · 2026-05-03T10:10:04Z

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ivankatliarchuk

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ivankatliarchuk · 2026-05-03T10:10:50Z

e2e #6017 (comment)

u-kai added 4 commits December 11, 2025 07:56

test: add regression test to ensure behavior before refactor

7fda240

Signed-off-by: u-kai <76635578+u-kai@users.noreply.github.com>

refactor aws adjustEndpointAndAaaaIfNeeded

b50b0a5

Signed-off-by: u-kai <76635578+u-kai@users.noreply.github.com>

fix clean up alias properties for unsupported record types

94dd0d3

Signed-off-by: u-kai <76635578+u-kai@users.noreply.github.com>

test add comprehensive tests and remove old logic

881e5c4

Signed-off-by: u-kai <76635578+u-kai@users.noreply.github.com>

k8s-ci-robot added the internal Issues or PRs related to internal code label Dec 12, 2025

k8s-ci-robot requested review from ivankatliarchuk and mloiseleur December 12, 2025 00:05

k8s-ci-robot added provider Issues or PRs related to a provider needs-ok-to-test Indicates a PR that requires an org member to verify it is safe to test. labels Dec 12, 2025

k8s-ci-robot added size/XL Denotes a PR that changes 500-999 lines, ignoring generated files. cncf-cla: yes Indicates the PR's author has signed the CNCF CLA. labels Dec 12, 2025

u-kai changed the title ~~Refactor alias-handling logic and fix incorrect behavior for non-aliasable record types~~ fix(aws): refactor alias-handling logic and fix incorrect behavior for non-aliasable record types Dec 12, 2025

u-kai mentioned this pull request Dec 12, 2025

feat(aws): support alias=A and alias=AAAA to create single record type #5997

Merged

3 tasks

u-kai mentioned this pull request Dec 12, 2025

refactor(aws): extract and restructure alias-handling logic to enable safe upcoming fixes #6021

Merged

3 tasks

u-kai changed the title ~~fix(aws): refactor alias-handling logic and fix incorrect behavior for non-aliasable record types~~ fix(aws): rfix incorrect behavior for non-aliasable record types Dec 12, 2025

u-kai changed the title ~~fix(aws): rfix incorrect behavior for non-aliasable record types~~ fix(aws): incorrect behavior for non-aliasable record types Dec 12, 2025

k8s-ci-robot added the needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. label Jan 27, 2026

u-kai added 2 commits January 28, 2026 21:55

Merge branch 'master' of https://github.com/kubernetes-sigs/external-dns

7be5ded

into fix/aws-alias-logic

fix: adjustOtherRecord

1ff3f5d

Signed-off-by: u-kai <76635578+u-kai@users.noreply.github.com>

k8s-ci-robot added size/M Denotes a PR that changes 30-99 lines, ignoring generated files. and removed needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. size/XL Denotes a PR that changes 500-999 lines, ignoring generated files. labels Jan 28, 2026

u-kai mentioned this pull request Feb 11, 2026

feat(endpoint): reject alias property on unsupported record types #6188

Merged

3 tasks

ivankatliarchuk mentioned this pull request Feb 18, 2026

feat(crd): Support MX record with trailing dot #6163

Merged

3 tasks

u-kai added 2 commits March 1, 2026 10:33

Merge branch 'master' of https://github.com/kubernetes-sigs/external-dns

a01ce04

into fix/aws-alias-logic

chore(aws): remove unnecessary adjustRecord method and its tests

b4b27fd

Signed-off-by: u-kai <76635578+u-kai@users.noreply.github.com>

k8s-ci-robot closed this Mar 31, 2026

k8s-ci-robot reopened this Mar 31, 2026

ivankatliarchuk reviewed Mar 31, 2026

View reviewed changes

Comment thread provider/aws/aws_test.go Outdated

u-kai and others added 4 commits April 3, 2026 07:29

Merge branch 'master' of https://github.com/kubernetes-sigs/external-dns

5d588c1

into fix/aws-alias-logic

fix typo provider/aws/aws_test.go

ba3279d

Co-authored-by: Ivan Ka <5395690+ivankatliarchuk@users.noreply.github.com>

Merge branch 'master' of https://github.com/kubernetes-sigs/external-dns

67f0f5a

into fix/aws-alias-logic

Merge branch 'fix/aws-alias-logic' of https://github.com/u-kai/extern…

d67f8fe

…al-dns into fix/aws-alias-logic

k8s-ci-robot added the lgtm "Looks good to me", indicates that a PR is ready to be merged. label May 3, 2026

k8s-ci-robot added the approved Indicates a PR has been approved by an approver from all required OWNERS files. label May 3, 2026

k8s-ci-robot merged commit ddd2cc3 into kubernetes-sigs:master May 3, 2026
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