{"record":{"id":"0916b96255555299","repo":"hashicorp/nomad","slug":"nil-response-from-plugin-nodeexpandvolume","errorCode":null,"errorMessage":"nil response from plugin.NodeExpandVolume","messagePattern":"nil response from plugin\\.NodeExpandVolume","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"client/pluginmanager/csimanager/volume.go","lineNumber":413,"sourceCode":"\t}\n\n\treq := &csi.NodeExpandVolumeRequest{\n\t\tExternalVolumeID: remoteID,\n\t\tCapacityRange:    capacity,\n\t\tCapability:       capability,\n\t\tTargetPath:       v.targetForVolume(v.containerMountPoint, volID, allocID, usage),\n\t\tStagingPath:      stagingPath,\n\t}\n\tresp, err := v.plugin.NodeExpandVolume(ctx, req,\n\t\tgrpc_retry.WithPerRetryTimeout(DefaultMountActionTimeout),\n\t\tgrpc_retry.WithMax(3),\n\t\tgrpc_retry.WithBackoff(grpc_retry.BackoffExponential(100*time.Millisecond)),\n\t)\n\tif err != nil {\n\t\treturn 0, err\n\t}\n\tif resp == nil {\n\t\treturn 0, errors.New(\"nil response from plugin.NodeExpandVolume\")\n\t}\n\treturn resp.CapacityBytes, nil\n}\n\nfunc (v *volumeManager) stagingDirForVolume(root string, volNS, volID string, usage *UsageOptions) string {\n\treturn filepath.Join(root, StagingDirName, volNS, volID, usage.ToFS())\n}\n\nfunc (v *volumeManager) allocDirForVolume(root string, volID, allocID string) string {\n\treturn filepath.Join(root, AllocSpecificDirName, allocID, volID)\n}\n\nfunc (v *volumeManager) targetForVolume(root string, volID, allocID string, usage *UsageOptions) string {\n\treturn filepath.Join(root, AllocSpecificDirName, allocID, volID, usage.ToFS())\n}\n\n// ensureStagingDir attempts to create a directory for use when staging a volume\n// and then validates that the path is not already a mount point for e.g an","sourceCodeStart":395,"sourceCodeEnd":431,"githubUrl":"https://github.com/hashicorp/nomad/blob/482b49bf1aec006f089bcfc7e632d8f6ac303e5e/client/pluginmanager/csimanager/volume.go#L395-L431","documentation":"This error is returned by expandVolumeImpl in the CSI volume manager when the gRPC NodeExpandVolume call succeeds (err == nil) but the plugin returns a nil response. Nomad treats that as a plugin protocol violation, since a valid response must carry CapacityBytes.","triggerScenarios":"Calling volume expansion against a CSI plugin whose NodeExpandVolume RPC returns success with a nil response — malformed or non-conformant CSI plugin behavior.","commonSituations":"Buggy or partially implemented third-party CSI drivers, plugin crashes mid-RPC returning empty success, or driver versions that don't implement NodeExpandVolume correctly.","solutions":["Upgrade the CSI plugin/driver to a version with correct NodeExpandVolume support","Retry the volume expansion; transient plugin failure may resolve","Check plugin logs for panics or malformed responses during expansion","Verify the driver is certified for the volume type being expanded"],"exampleFix":null,"handlingStrategy":"retry","validationCode":null,"typeGuard":"func validExpandResp(resp *csi.NodeExpandVolumeResponse) bool { return resp != nil && resp.CapacityBytes > 0 }","tryCatchPattern":"bytes, err := manager.expandVolumeImpl(ctx, req)\nif err != nil && strings.Contains(err.Error(), \"nil response from plugin.NodeExpandVolume\") {\n    // retry expand; if persistent, restart/upgrade the CSI plugin\n    return retryExpandWithBackoff(ctx, req)\n}","preventionTips":["Use certified, current CSI drivers that fully implement NodeExpandVolume","Monitor plugin logs for panics during expansion","Retry transient expand failures with backoff","Test volume expansion workflows when upgrading CSI plugins"],"tags":["go","csi","grpc","volume-expansion"],"backgroundTag":"nil-response-from-plugin","analyzedSha":"482b49bf1aec006f089bcfc7e632d8f6ac303e5e","analyzedAt":"2026-09-04T07:54:14.808Z","contentChangedAt":"2026-09-04T07:54:14.808Z","schemaVersion":2},"datasetVersion":"2026-09-08T10:18:20.063Z"}