[CP 1267] DCM: mount default ConfigMap when spec.configManager.config is omitted and it's E2Es

[ci-penbot-01]

cp of pensando/gpu-operator#1267

---

Source PR Description (pensando/gpu-operator#1267):

Summary

When Device Config Manager is enabled on a DeviceConfig:

• If spec.configManager.config is unset or the referenced name is empty, the DCM DaemonSet mounts ConfigMap default-dcm-config in the DeviceConfig namespace and exposes it at /etc/config-manager/ (typically config.json).
• If spec.configManager.config.name is set, the DaemonSet mounts that ConfigMap instead; the operator does not create or manage that object—the cluster admin must supply it.

New behavior (default ConfigMap lifecycle)

• Operator: Before reconciling the DCM DaemonSet, the operator ensures default-dcm-config exists when the default mount is in use. If the ConfigMap is missing, it is created with a built-in default config.json (embedded in the operator binary from internal/configmanager/default_dcm_config.json). If it already exists (e.g. from Helm or a prior run), it is not overwritten.
• Helm: The chart can install the same default-dcm-config in the release namespace by default (defaultDCMConfigMap in values.yaml, new template). Operators can turn this off or override data for site-specific profiles. Chart config.json content should stay aligned with the embedded JSON used by the operator.

API / docs

• ConfigManagerSpec.Config doc updated to describe default vs explicit ConfigMap behavior.
• Published-oriented updates in docs/dcm/device-config-manager-configmap.md (behavior without internal function/file callouts where appropriate).

E2E

• ensureDefaultDCMConfigMap: if default-dcm-config already has non-empty config.json (e.g. Helm), tests do not delete/recreate it; otherwise the test fixture is applied.
• verifyDCMConfigMapVolumeRef: asserts the DCM DaemonSet uses the expected ConfigMap on the config-manager volume.
• TestDCMDefaultConfigMapWhenConfigOmitted: SIM-friendly check that DCM comes up with no spec.configManager.config and the default ConfigMap name is mounted.
• SIM vs GPU: skipDCMTestIfSIMRequiresGPU and related skips adjusted so partition / GPU-only tests skip under SIM while K8s-only checks can run.
• dev.env: E2E_DCM_IMAGE bumped to device-config-manager:v1.4.1 for tests that pull DCM.

Test results

cd ~/gpu-operator/tests/e2e
make dcm_e2e
# equivalent: go test -test.timeout=360m -check.f 'TestDCM.*' -v \
#   -deviceConfigName test-deviceconfig -simEnable

OK: 2 passed, 7 skipped
--- PASS: Test (318.06s)
PASS
ok  	github.com/ROCm/gpu-operator/tests/e2e	318.082s

Cherrypick triggered by: ACP-Automation

[ci-penbot-01]

AI-Assisted Cherry-Pick

Source PR: #1267
Target Branch: main

The cherry-pick operation encountered merge conflicts which were resolved automatically using AI assistance.

Files with conflicts (resolved by AI):

• bundle/manifests/amd-gpu-operator.clusterserviceversion.yaml:38-44

Original conflict in bundle/manifests/amd-gpu-operator.clusterserviceversion.yaml

<<<<<<< HEAD
    containerImage: docker.io/rocm/amd-gpu-operator:dev
    createdAt: "2026-04-02T12:26:30Z"
=======
    containerImage: registry.test.pensando.io:5000/amd-gpu-operator:dev
    createdAt: "2026-04-06T08:31:30Z"
>>>>>>> e9c1e916... DCM: mount default ConfigMap when spec.configManager.config is omitted and it's E2Es (#1267)

Cherry-pick triggered by: ACP-Automation