ci: install kmod (depmod) before microVM image build (e2e + nightly + ddil) (#307)

* ci(e2e): install kmod (depmod) before microVM image build

#305 made depmod a hard requirement in build-microvm-image.sh, but the
self-hosted ci-single/ci-multi runners don't ship the kmod package, so the
Build Install Artifacts step aborts with 'required tool not found: depmod'
before any E2E suite runs. Add an idempotent kmod install ahead of each
Build Install Artifacts step (single/multi/eks jobs); the gold-image builder
bakes kmod in too, so this no-ops once runners pick up the new image.

* ci: install kmod (depmod) in nightly + ddil too

e2e-nightly and e2e-ddil call the same build-install-artifacts.sh (-> make
build-microvm-image) on the same self-hosted ci-single/ci-multi runners as
e2e.yml, so they hit the identical 'depmod not found' abort. Add the same
idempotent kmod guard before Build Install Artifacts in both.

release distro builds run on GitHub-hosted ubuntu (kmod present); e2e-baremetal
runs on ci-baremetal which already has it (green today) — neither needs the
guard.

.github/workflows/e2e-ddil.yml

@@ -76,6 +76,14 @@ jobs:
           echo "${BIN_DIR}" >> "${GITHUB_PATH}"
           "${BIN_DIR}/gotestsum" --version
 
+      - name: Install kmod (depmod)
+        # build-microvm-image's mandatory-tool preflight requires depmod (from
+        # the kmod package); self-hosted runners don't ship it. Idempotent —
+        # no-op once baked into the runner/gold image.
+        run: |
+          command -v depmod >/dev/null 2>&1 || \
+            { sudo apt-get update -qq && sudo apt-get install -y --no-install-recommends kmod; }
+
       - name: Build Install Artifacts
         working-directory: mulga/scripts/tofu-cluster
         run: |

.github/workflows/e2e-nightly.yml

@@ -78,6 +78,15 @@ jobs:
           sparse-checkout: scripts/tofu-cluster
           path: mulga
 
+      - name: Install kmod (depmod)
+        if: steps.gate.outputs.selected == 'true'
+        # build-microvm-image's mandatory-tool preflight requires depmod (from
+        # the kmod package); self-hosted runners don't ship it. Idempotent —
+        # no-op once baked into the runner/gold image.
+        run: |
+          command -v depmod >/dev/null 2>&1 || \
+            { sudo apt-get update -qq && sudo apt-get install -y --no-install-recommends kmod; }
+
       - name: Build Install Artifacts
         if: steps.gate.outputs.selected == 'true'
         working-directory: mulga/scripts/tofu-cluster

.github/workflows/e2e.yml

@@ -113,6 +113,14 @@ jobs:
           docker buildx prune -af --filter "until=24h" || true
           docker system df || true
 
+      - name: Install kmod (depmod)
+        # build-microvm-image's mandatory-tool preflight requires depmod (from
+        # the kmod package) to generate modules.dep; self-hosted runners don't
+        # ship it. Idempotent — no-op once baked into the runner/gold image.
+        run: |
+          command -v depmod >/dev/null 2>&1 || \
+            { sudo apt-get update -qq && sudo apt-get install -y --no-install-recommends kmod; }
+
       - name: Build Install Artifacts
         working-directory: mulga/scripts/tofu-cluster
         run: |
@@ -512,6 +520,14 @@ jobs:
           docker buildx prune -af --filter "until=24h" || true
           docker system df || true
 
+      - name: Install kmod (depmod)
+        # build-microvm-image's mandatory-tool preflight requires depmod (from
+        # the kmod package) to generate modules.dep; self-hosted runners don't
+        # ship it. Idempotent — no-op once baked into the runner/gold image.
+        run: |
+          command -v depmod >/dev/null 2>&1 || \
+            { sudo apt-get update -qq && sudo apt-get install -y --no-install-recommends kmod; }
+
       - name: Build Install Artifacts
         working-directory: mulga/scripts/tofu-cluster
         run: |
@@ -928,6 +944,14 @@ jobs:
           docker buildx prune -af --filter "until=24h" || true
           docker system df || true
 
+      - name: Install kmod (depmod)
+        # build-microvm-image's mandatory-tool preflight requires depmod (from
+        # the kmod package) to generate modules.dep; self-hosted runners don't
+        # ship it. Idempotent — no-op once baked into the runner/gold image.
+        run: |
+          command -v depmod >/dev/null 2>&1 || \
+            { sudo apt-get update -qq && sudo apt-get install -y --no-install-recommends kmod; }
+
       - name: Build Install Artifacts
         working-directory: mulga/scripts/tofu-cluster
         run: |