Custom disk volume sizes not being applied with pod manifests

[joshhalley]

Problem Statement

Currently disk volume size specified via ephemeral-storage in a pod spec is not being applied to the IOS-XE app-hosting configuration. The persist-disk parameter always defaults to 1024 MB regardless of the value specified in the pod manifest.

Example pod spec:

resources:
  requests:
    ephemeral-storage: "10Mi"
  limits:
    ephemeral-storage: "15Mi"

Expected IOS-XE configuration:

app-resource profile custom
  persist-disk 15

Actual IOS-XE configuration:

app-resource profile custom
  persist-disk 1024

Proposed Solution

The bug is in internal/drivers/iosxe/transformers.go line 379. The code uses Storage() method which returns the storage resource (for PersistentVolumes), not ephemeral-storage.

Current code:

if storage := container.Resources.Requests.Storage(); storage != nil && !storage.IsZero() {
    config.diskMB = uint16(storage.Value() / (1024 * 1024))
}

Fix:

if storage, ok := container.Resources.Requests[v1.ResourceEphemeralStorage]; ok && !storage.IsZero() {
    config.diskMB = uint16(storage.Value() / (1024 * 1024))
}

This accesses ephemeral-storage directly from the ResourceList using the v1.ResourceEphemeralStorage constant.

Alternatives Considered

1. Use a custom extended resource (e.g., cisco.com/persist-disk) - Rejected because Kubernetes already provides ephemeral-storage as a standard resource type, and using it maintains compatibility with standard Kubernetes tooling.

2. Use annotations - Rejected because resource requests/limits are the idiomatic Kubernetes way to specify container resource requirements.

Additional Context

• The YANG model disk-size-mb correctly maps to the CLI persist-disk parameter
• The default value of 1024 MB is set in getResourceConfig() and is only overwritten if the storage value is successfully read
• This affects all deployments attempting to specify custom disk sizes via pod specs

[joshhalley]

Related to Issue #5