Bug | ArgoCD Fails Login on Existing cluster

[otavioss]

Describe the bug

When running the tool with --create-cluster=false it fails to log in to the cluster ArgoCD server

Expected behaviour

Login successfull

Standard output (with --debug flag)

...
🦑 Logging in to Argo CD through CLI...
Argo CD login attempt 1/10 failed. error="argocd command failed: {\"level\":\"fatal\",\"msg\":\"Failed to establish connection to 127.0.0.1:36969: EOF\",\"time\":\"2025-10-10T20:04:57Z\"}\n: exit status 1"
Argo CD login attempt 2/10 failed. error="argocd command failed: {\"level\":\"fatal\",\"msg\":\"Failed to establish connection to 127.0.0.1:45315: EOF\",\"time\":\"2025-10-10T20:05:01Z\"}\n: exit status 1"
Argo CD login attempt 3/10 failed. error="argocd command failed: {\"level\":\"fatal\",\"msg\":\"Failed to establish connection to 127.0.0.1:36431: EOF\",\"time\":\"2025-10-10T20:05:06Z\"}\n: exit status 1"
Argo CD login attempt 4/10 failed. error="argocd command failed: {\"level\":\"fatal\",\"msg\":\"Failed to establish connection to 127.0.0.1:44035: EOF\",\"time\":\"2025-10-10T20:05:10Z\"}\n: exit status 1"
Argo CD login attempt 5/10 failed. error="argocd command failed: {\"level\":\"fatal\",\"msg\":\"Failed to establish connection to 127.0.0.1:39055: EOF\",\"time\":\"2025-10-10T20:05:14Z\"}\n: exit status 1"
Argo CD login attempt 6/10 failed. error="argocd command failed: {\"level\":\"fatal\",\"msg\":\"Failed to establish connection to 127.0.0.1:46065: EOF\",\"time\":\"2025-10-10T20:05:18Z\"}\n: exit status 1"
Argo CD login attempt 7/10 failed. error="argocd command failed: {\"level\":\"fatal\",\"msg\":\"Failed to establish connection to 127.0.0.1:33623: EOF\",\"time\":\"2025-10-10T20:05:22Z\"}\n: exit status 1"
Argo CD login attempt 8/10 failed. error="argocd command failed: {\"level\":\"fatal\",\"msg\":\"Failed to establish connection to 127.0.0.1:39349: EOF\",\"time\":\"2025-10-10T20:05:27Z\"}\n: exit status 1"
Argo CD login attempt 9/10 failed. error="argocd command failed: {\"level\":\"fatal\",\"msg\":\"Failed to establish connection to 127.0.0.1:36003: EOF\",\"time\":\"2025-10-10T20:05:31Z\"}\n: exit status 1"
❌ Failed to login to Argo CD after 10 attempts error="argocd command failed: {\"level\":\"fatal\",\"msg\":\"Failed to establish connection to 127.0.0.1:37737: EOF\",\"time\":\"2025-10-10T20:05:35Z\"}\n: exit status 1"
❌ Failed to login to Argo CD
❌ failed to login: failed to login after 10 attempts

Parameters

✨ Running v0.1.18 (2025-10-01T17:40:49Z) with:
✨ - reusing existing cluster
✨ - base-branch: main
✨ - target-branch: refs/pull/50665/merge
✨ - secrets-folder: ./secrets
✨ - output-folder: ./output
✨ - argocd-namespace: argo-cd
✨ - repo: VibrentHealth/cluster-state
✨ - timeout: 180 seconds
✨ - debug: true - This is slower because it will do more checks
✨ - files-changed: auto-detected
  ...

[otavioss]

On line https://github.com/dag-andersen/argocd-diff-preview/blob/main/pkg/argocd/argocd.go#L321 it's missing --plaintext for newer versions of ArgoCD

[dag-andersen]

Hi @otavioss!
Which Argo CD version are you running in the cluster?
When I run make run-integration-tests-docker or make run-integration-tests-go with your --plaintext flag change, the tool can’t connect to Argo CD. But if I remove it, it works perfectly fine. Both integration tests make use of reusing an existing cluster.

[otavioss]

Hello!
I'm using version argocd v3.0.19.
It might be something specific to my environment, as we have some custom TLS certs.
Maybe the solution would be having runArgocdCommand parameter options ?

[otavioss]

Hi @dag-andersen I have updated the pull request. Can you please take a look? #237

[dag-andersen]

Thank you @otavioss
Have you tried using the --skip-test-tls option instead of --plaintext? That one doesn’t break my tests and might solve your problem.

Do you actually need the custom Argo CD user account login and --grpc-web, or did you just choose to implement it? :)

[otavioss]

Hi @dag-andersen yes, I did try to use it

argocd login --skip-test-tls  --port-forward --port-forward-namespace=argo-cd --insecure --username <redacted> --password <redacted>
{"level":"fatal","msg":"Failed to establish connection to 127.0.0.1:54136: EOF","time":"2025-10-15T12:28:35+01:00"}

The only thing that works for me is the --plaintext

argocd login --port-forward --port-forward-namespace=argo-cd --insecure --username <redacted> --password <redacted> --plaintext
'admin:login' logged in successfully
Context 'port-forward' updated

I added --grpc-web just because I was already adding the other options 😅

EDIT: BTW, I tried using a mounted kubeconfig and also a service account, and both produce the same behaviour

[dag-andersen]

@otavioss

First of all, thank you for taking the time to create a PR for this 🚀

After thinking about it today, I would prefer that we do not implement plaintext, grpc-web, etc. individually, but instead create an option called --argocd-login-options that is appended to the already existing parameters - similar to what you’re suggesting here:

Maybe the solution would be having runArgocdCommand parameter options?

Why?

• This way, users can define whatever they want, and I don’t need to maintain the individual implementations. I don’t want to add a new option every time Argo CD releases or updates their options. I’d rather keep it flexible and let users define whatever they want.

• I don’t want to release something I can’t guarantee works or have tests for. Since I haven’t been able to reproduce the issue you’re seeing, I can’t make a test for it and therefore can’t guarantee that I won’t accidentally break it in the future.

• I don’t want to support any features I can’t test or verify work - otherwise, people will start complaining. I think most users understand that using an open-ended option like --argocd-login-options isn’t guaranteed to work in all cases. It’s similar to how users can provide the tool with any Argo CD Helm chart configuration, but shouldn’t expect all configurations to work. Following that logic, I’m happy to let users run the tool however they want, but I don’t guarantee it works when customizing the login mechanism.

[nichcuta]

I'm experiencing this myself when using an already provisioned argoCD instance v2.14. Only method that worked was passing the --plaintext parameter as mentioned by @otavioss