#Unable to Use Multiple PVC Workspaces in Tekton

#Problem Description

When running a PipelineRun or TaskRun in Tekton with multiple PersistentVolumeClaim (PVC)-based workspaces, the execution fails with an error similar to "more than one PersistentVolumeClaim is bound".

This occurs even if all PVCs are valid and correctly declared.

#Error Manifestation

1. TaskRun execution fails with a status of False, and the reason is TaskRunValidationFailed:

   $ kubectl get taskruns -n ${namespace} ${taskrun_name}
   NAME                     SUCCEEDED   REASON                       STARTTIME   COMPLETIONTIME
   demo-hbfhd-foo           False       TaskRunValidationFailed      59s         59s

2. The TaskRun event displays an error message:

   [User error] more than one PersistentVolumeClaim is bound

#Root Cause Analysis

By default, Tekton enables the Affinity Assistant feature to help co-locate TaskRun pods with their PVCs on the same node. This is especially useful for volumes with ReadWriteOnce access mode.

However, when the Affinity Assistant is enabled:

• Each TaskRun is limited to a single PVC-based workspace.
• Binding more than one PVC triggers a validation error, preventing the TaskRun from running.

This restriction is enforced to avoid complex scheduling issues and node affinity conflicts.

#Troubleshooting

To allow a TaskRun or PipelineRun to use multiple PVC-based workspaces, you must disable the Affinity Assistant by updating the Tekton feature flags.

It is recommended to troubleshoot as follows:

1. Edit the TektonConfig resource by setting spec.pipeline.disable-affinity-assistant as shown below:

   apiVersion: operator.tekton.dev/v1alpha1
   kind: TektonConfig
   spec:
     pipeline:
       disable-affinity-assistant: true

   tips: the disable-affinity-assistant feature flag will be removed soon and the Affinity Assistant Modes will be only controlled by the coschedule feature flag.

2. The feature-flags ConfigMap will be updated automatically.

   apiVersion: v1
   kind: ConfigMap
   metadata:
     name: feature-flags
     namespace: tekton-pipelines
   data:
     disable-affinity-assistant: "true"

3. No manual component restarts are required, changes will take effect automatically.

#Related Content

• Tekton Affinity Assistant
• Tekton Workspaces