Kubernetes publisher fails when adding a pipeline step that depends on "prepare-deployment-targets-{environment}"

[cdbrown2018]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

When attempting to run aspire publish or aspire publish --list-steps on an AppHost that has a custom pipeline step registered that depends on prepare-deployment-targets-{env}, the publisher fails, complaining about duplicate Kubernetes environments.

Expected Behavior

Running aspire publish should complete successfully even when pipeline steps are registered with dependencies on the step that prepares deployment targets.

Steps To Reproduce

var builder = DistributedApplication.CreateBuilder();

var k8s = builder.AddKubernetesEnvironment("k8s");

var step = new PipelineStep
{
    Name = "faulty-pipeline-step",
    Action = async (ctx) => Task.CompletedTask
};
step.DependsOn("prepare-deployment-targets-k8s");
step.RequiredBy("publish-k8s");
builder.Pipeline.AddStep(step);

builder.Build().Run();

Exceptions (if any)

fail: Aspire.Hosting.Publishing.PipelineExecutor[0]
      Step 'prepare-deployment-targets-k8s' failed.
      System.InvalidOperationException: Step 'prepare-deployment-targets-k8s' failed: Resource 'k8s-dashboard' has
multiple compute environments - 'k8s, k8s'. Please specify a single compute environment using 
'WithComputeEnvironment'.
       ---> System.InvalidOperationException: Resource 'k8s-dashboard' has multiple compute environments - 'k8s, 
k8s'. Please specify a single compute environment using 'WithComputeEnvironment'.
         at Aspire.Hosting.ApplicationModel.ResourceExtensions.GetDeploymentTargetAnnotation(IResource resource, 
IComputeEnvironmentResource targetComputeEnvironment) in 
/_/src/Aspire.Hosting/ApplicationModel/ResourceExtensions.cs:line 1071
         at Aspire.Hosting.ComputeEnvironmentEndpointResolver.TryGetEffectiveComputeEnvironment(IResource 
resource, IComputeEnvironmentResource& computeEnvironment) in 
/_/src/Shared/ComputeEnvironmentEndpointResolver.cs:line 134
         at 
Aspire.Hosting.ComputeEnvironmentEndpointResolver.TryGetCrossEnvironmentEndpointExpression(EndpointReferenceExpres
sion endpointReferenceExpression, IReadOnlyList`1 currentComputeEnvironments, ReferenceExpression& expression) in 
/_/src/Shared/ComputeEnvironmentEndpointResolver.cs:line 89
         at 
Aspire.Hosting.ComputeEnvironmentEndpointResolver.TryGetCrossEnvironmentEndpointExpression(EndpointReference 
endpointReference, IReadOnlyList`1 currentComputeEnvironments, ReferenceExpression& expression) in 
/_/src/Shared/ComputeEnvironmentEndpointResolver.cs:line 50
         at Aspire.Hosting.Kubernetes.KubernetesResource.ProcessValueAsync(KubernetesEnvironmentContext context, 
DistributedApplicationExecutionContext executionContext, Object value, Boolean embedded) in 
/_/src/Aspire.Hosting.Kubernetes/KubernetesResource.cs:line 510
         at Aspire.Hosting.Kubernetes.KubernetesResource.ProcessEnvironmentAsync(KubernetesEnvironmentContext 
environmentContext, DistributedApplicationExecutionContext executionContext, CancellationToken cancellationToken) 
in /_/src/Aspire.Hosting.Kubernetes/KubernetesResource.cs:line 421
         at Aspire.Hosting.Kubernetes.KubernetesResource.ProcessResourceAsync(KubernetesEnvironmentContext 
context, DistributedApplicationExecutionContext executionContext, CancellationToken cancellationToken) in 
/_/src/Aspire.Hosting.Kubernetes/KubernetesResource.cs:line 224
         at Aspire.Hosting.Kubernetes.KubernetesEnvironmentContext.CreateKubernetesResourceAsync(IResource 
resource, DistributedApplicationExecutionContext executionContext, CancellationToken cancellationToken) in 
/_/src/Aspire.Hosting.Kubernetes/KubernetesEnvironmentContext.cs:line 27
         at 
Aspire.Hosting.Kubernetes.KubernetesEnvironmentResource.PrepareDeploymentTargetsAsync(PipelineStepContext context)
in /_/src/Aspire.Hosting.Kubernetes/KubernetesEnvironmentResource.cs:line 501
         at Aspire.Hosting.Pipelines.DistributedApplicationPipeline.ExecuteStepAsync(PipelineStep step, 
PipelineStepContext stepContext) in /_/src/Aspire.Hosting/Pipelines/DistributedApplicationPipeline.cs:line 1136
         --- End of inner exception stack trace ---
         at Aspire.Hosting.Pipelines.DistributedApplicationPipeline.ExecuteStepAsync(PipelineStep step, 
PipelineStepContext stepContext) in /_/src/Aspire.Hosting/Pipelines/DistributedApplicationPipeline.cs:line 1148
         at 
Aspire.Hosting.Pipelines.DistributedApplicationPipeline.<>c__DisplayClass24_0.<<ExecuteStepsAsTaskDag>g__ExecuteSt
epWithDependencies|0>d.MoveNext() in /_/src/Aspire.Hosting/Pipelines/DistributedApplicationPipeline.cs:line 913
info: Aspire.Hosting.ParameterProcessor[0]
      34 parameter values saved to deployment state.
fail: Aspire.Hosting.Publishing.PipelineExecutor[0]
      Step 'prepare-deployment-targets-k8s' failed: Resource 'k8s-dashboard' has multiple compute environments - 
'k8s, k8s'. Please specify a single compute environment using 'WithComputeEnvironment'.
      System.InvalidOperationException: Step 'prepare-deployment-targets-k8s' failed: Resource 'k8s-dashboard' has
multiple compute environments - 'k8s, k8s'. Please specify a single compute environment using 
'WithComputeEnvironment'.
       ---> System.InvalidOperationException: Resource 'k8s-dashboard' has multiple compute environments - 'k8s, 
k8s'. Please specify a single compute environment using 'WithComputeEnvironment'.
         at Aspire.Hosting.ApplicationModel.ResourceExtensions.GetDeploymentTargetAnnotation(IResource resource, 
IComputeEnvironmentResource targetComputeEnvironment) in 
/_/src/Aspire.Hosting/ApplicationModel/ResourceExtensions.cs:line 1071
         at Aspire.Hosting.ComputeEnvironmentEndpointResolver.TryGetEffectiveComputeEnvironment(IResource 
resource, IComputeEnvironmentResource& computeEnvironment) in 
/_/src/Shared/ComputeEnvironmentEndpointResolver.cs:line 134
         at 
Aspire.Hosting.ComputeEnvironmentEndpointResolver.TryGetCrossEnvironmentEndpointExpression(EndpointReferenceExpres
sion endpointReferenceExpression, IReadOnlyList`1 currentComputeEnvironments, ReferenceExpression& expression) in 
/_/src/Shared/ComputeEnvironmentEndpointResolver.cs:line 89
         at 
Aspire.Hosting.ComputeEnvironmentEndpointResolver.TryGetCrossEnvironmentEndpointExpression(EndpointReference 
endpointReference, IReadOnlyList`1 currentComputeEnvironments, ReferenceExpression& expression) in 
/_/src/Shared/ComputeEnvironmentEndpointResolver.cs:line 50
         at Aspire.Hosting.Kubernetes.KubernetesResource.ProcessValueAsync(KubernetesEnvironmentContext context, 
DistributedApplicationExecutionContext executionContext, Object value, Boolean embedded) in 
/_/src/Aspire.Hosting.Kubernetes/KubernetesResource.cs:line 510
         at Aspire.Hosting.Kubernetes.KubernetesResource.ProcessEnvironmentAsync(KubernetesEnvironmentContext 
environmentContext, DistributedApplicationExecutionContext executionContext, CancellationToken cancellationToken) 
in /_/src/Aspire.Hosting.Kubernetes/KubernetesResource.cs:line 421
         at Aspire.Hosting.Kubernetes.KubernetesResource.ProcessResourceAsync(KubernetesEnvironmentContext 
context, DistributedApplicationExecutionContext executionContext, CancellationToken cancellationToken) in 
/_/src/Aspire.Hosting.Kubernetes/KubernetesResource.cs:line 224
         at Aspire.Hosting.Kubernetes.KubernetesEnvironmentContext.CreateKubernetesResourceAsync(IResource 
resource, DistributedApplicationExecutionContext executionContext, CancellationToken cancellationToken) in 
/_/src/Aspire.Hosting.Kubernetes/KubernetesEnvironmentContext.cs:line 27
         at 
Aspire.Hosting.Kubernetes.KubernetesEnvironmentResource.PrepareDeploymentTargetsAsync(PipelineStepContext context)
in /_/src/Aspire.Hosting.Kubernetes/KubernetesEnvironmentResource.cs:line 501
         at Aspire.Hosting.Pipelines.DistributedApplicationPipeline.ExecuteStepAsync(PipelineStep step, 
PipelineStepContext stepContext) in /_/src/Aspire.Hosting/Pipelines/DistributedApplicationPipeline.cs:line 1136
         --- End of inner exception stack trace ---
         at Aspire.Hosting.Pipelines.DistributedApplicationPipeline.ExecuteStepAsync(PipelineStep step, 
PipelineStepContext stepContext) in /_/src/Aspire.Hosting/Pipelines/DistributedApplicationPipeline.cs:line 1148
         at 
Aspire.Hosting.Pipelines.DistributedApplicationPipeline.<>c__DisplayClass24_0.<<ExecuteStepsAsTaskDag>g__ExecuteSt
epWithDependencies|0>d.MoveNext() in /_/src/Aspire.Hosting/Pipelines/DistributedApplicationPipeline.cs:line 913
      --- End of stack trace from previous location ---
         at 
Aspire.Hosting.Pipelines.DistributedApplicationPipeline.<>c__DisplayClass24_0.<<ExecuteStepsAsTaskDag>g__ExecuteSt
epWithDependencies|0>d.MoveNext() in /_/src/Aspire.Hosting/Pipelines/DistributedApplicationPipeline.cs:line 921
      --- End of stack trace from previous location ---
         at 
Aspire.Hosting.Pipelines.DistributedApplicationPipeline.<>c__DisplayClass24_0.<<ExecuteStepsAsTaskDag>g__ExecuteSt
epWithDependencies|0>d.MoveNext() in /_/src/Aspire.Hosting/Pipelines/DistributedApplicationPipeline.cs:line 927
      --- End of stack trace from previous location ---
         at Aspire.Hosting.Pipelines.DistributedApplicationPipeline.ExecuteStepsAsTaskDag(List`1 steps, 
Dictionary`2 stepsByName, PipelineContext context) in 
/_/src/Aspire.Hosting/Pipelines/DistributedApplicationPipeline.cs:line 951
         at Aspire.Hosting.Pipelines.DistributedApplicationPipeline.ExecuteAsync(PipelineContext context) in 
/_/src/Aspire.Hosting/Pipelines/DistributedApplicationPipeline.cs:line 585
         at Aspire.Hosting.Publishing.PipelineExecutor.ExecutePipelineAsync(DistributedApplicationModel model, 
CancellationToken cancellationToken) in /_/src/Aspire.Hosting/Publishing/PipelineExecutor.cs:line 106
         at Aspire.Hosting.Publishing.PipelineExecutor.ExecuteAsync(CancellationToken stoppingToken) in 
/_/src/Aspire.Hosting/Publishing/PipelineExecutor.cs:line 55

Aspire doctor output

Aspire Environment Check
========================

Aspire
  ⚠️ Aspire CLI version 13.5.2 (channel: stable) is out of date. Latest version is 13.5.3 (channel: stable)  
       Run 'aspire update' to update Aspire CLI.       
  ✅ Developer Control Plane (DCP) connection health checks succeeded  

AppHost
  ✅ AppHost version 13.5.2 (channel: daily) (VisualRfAspire.csproj)  

.NET SDK
  ✅ .NET 10.0.300 installed (x64)  

Container Runtime
  ✅ Docker: running (auto-detected (default)) ← active  

Environment
  ✅ Operating system: Linux Ubuntu 24.04  
  ✅ WSL2 environment detected  
       Details:                                                                                                 
       If you experience container connectivity issues, ensure Docker Desktop WSL integration is enabled.       
  ✅ HTTPS development certificate is trusted  
  ⚠️ certutil is not available; browser certificate trust may be incomplete  
       Install certutil from your distribution's NSS tools package (for example, libnss3-tools).                  
       See: https://aka.ms/aspire-prerequisites#dev-certs                                                         
       Details:                                                                                                   
       Aspire uses certutil to query and update NSS certificate databases used by Firefox and Chromium            
       browsers on Linux.                                                                                         

Development Tools
  ✅ Aspire extension for VS Code is installed  

Summary: 8 passed, 2 warnings, 0 failed
For detailed prerequisites: https://aka.ms/aspire-prerequisites

Aspire CLI Installations
========================

╭──────────────────────────────────┬─────────────────────────────────┬──────────────┬──────────────┬─────────────╮
│ Path                             │ Version                         │ Channel      │ Route        │ PATH status │
├──────────────────────────────────┼─────────────────────────────────┼──────────────┼──────────────┼─────────────┤
│ /home/vscode/.aspire/bin/aspire  │ 13.5.2+a22cec24d76e764b3681977e │ stable       │ script       │ active      │
│ (current)                        │ 314ab4a0aeed0240                │              │              │             │
│ /usr/local/bin/aspire            │ (not probed)                    │ (not probed) │ (not probed) │ shadowed    │
╰──────────────────────────────────┴─────────────────────────────────┴──────────────┴──────────────┴─────────────╯

Anything else?

aspire doctor is reporting an Aspire 13.5.3 release, which at the time of writing is not publicly released on GitHub.

I have a log file, however it contains a lot of information I'd rather not share publicly. I can sanitize it and share it here if it would be helpful. Though, the only thing I see that would be relevant is the exception that I included already.

[MihuBot]

I'm a bot. Here is a possible related and/or duplicate issue (I may be wrong):

• aspire publish --publisher docker-compose crashes with 'Sequence contains more than one matching element' #17392

[joperezr]

🤖 Aspire triage pass — 2026-08-25 21:24 UTC

Area: area-deployment, area-integrations
Kind: bug
Repro: yes-minimal — see the "Steps To Reproduce" C# snippet in the issue body
Affected version(s): 13.5.2 (CLI stable + AppHost daily; latest reported by doctor: 13.5.3)
Severity: S3 — aspire publish fails when a custom pipeline step depends on the internal prepare-deployment-targets-{env} step for a Kubernetes environment; a workaround likely exists (avoid depending directly on that internal step). The failure surfaces as a self-duplicate compute environment ('k8s, k8s') in KubernetesEnvironmentResource.PrepareDeploymentTargetsAsync / ResourceExtensions.GetDeploymentTargetAnnotation.

Urgency: ⚪ backlog — no milestone
Reason: S3 bug with a likely workaround; no evidence it regressed from a prior 13.x (not a regression) and not an S1/S2 no-workaround break, so it does not clear the raised 13.6/13.5.x bar. Defaulting to Backlog for a human to pull up if warranted.

Suggested owner(s): Mitch Denny (@mitchdenny) (score 11), backup David Fowler (@davidfowl) (score 4)
Evidence:

• mitchdenny merged Fix Kubernetes hostname publishing and routing #19430, Fix Kubernetes values for embedded environment parameters #19429 (2026-08-24) and Set a default fsGroup for Kubernetes persistent volumes #19374 (2026-08-15), plus Add first-class KubernetesPersistentVolumeResource (and fix related YAML serializer bugs) #16929, in area-deployment (most recent deployment PRs)
• davidfowl merged Fix Kubernetes GetEndpoint resolving to targetPort instead of service port #18630 in area-deployment and has recent area-integrations activity (Fix cross-scope ACR pull identities #18742, Add App Service delegated subnet support #18738)
• CODEOWNERS attributes tests/Aspire.Hosting.Tests to Mitch Denny (@mitchdenny); no dedicated Kubernetes/pipelines CODEOWNERS entry matched

Confidence: medium
Needs human?: no

[cdbrown2018]

This bug appears to have been fixed in the 13.6 daily builds. Closing for now.