gha/vm: Limit to cgroup-related integration packages

Running the entire integration test suite in a VM is very long and takes
almost an hour. Combined with flaky tests this puts heavy burden on the
CI resources.

Since the primary purpose of the VM tests is to validate cgroup v1
functionality (using Oracle Linux 8), make it only run integration
packages that contain cgroup-specific test coverage.

Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>

.github/workflows/.vm.yml

@@ -18,6 +18,11 @@ on:
       template:
         required: true
         type: string
+      integration_dir:
+        description: If set, only run integration tests from these directories (space-separated)
+        required: false
+        type: string
+        default: ""
 
 env:
   GO_VERSION: "1.25.7"
@@ -137,6 +142,7 @@ jobs:
           # TODO: enable GHA cache?
           LIMA_WORKDIR=/tmp/docker lima \
             TEST_SKIP_INTEGRATION_CLI=1 \
+            TEST_INTEGRATION_DIR="${{ inputs.integration_dir }}" \
             TEST_INTEGRATION_USE_GRAPHDRIVER=1 \
             DOCKER_ROOTLESS=${DOCKER_ROOTLESS} \
             DOCKER_GRAPHDRIVER=${DOCKER_GRAPHDRIVER} \

.github/workflows/vm.yml

@@ -33,14 +33,20 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        template:
+        include:
           # EL 8 is used for running the tests with cgroup v1.
           # Do not upgrade this to EL 9 until formally deprecating the cgroup v1 support.
           #
+          # To minimize CI time the whole test suite takes, only run
+          # integration packages that currently contain cgroup-v1/v2 specific
+          # coverage (cgroup namespaces, cgroup driver/systemd, and resource
+          # update verification via /sys/fs/cgroup paths).
+          #
           # FIXME: use almalinux-8, then probably no need to keep oraclelinux-8 here.
           # On almalinux-8, port forwarding tests are failing:
           # https://github.com/moby/moby/pull/49819#issuecomment-2815676000
-          - template:oraclelinux-8  # Oracle's kernel 5.15
-          # - template:almalinux-8  # kernel 4.18
+          - template: template:oraclelinux-8  # Oracle's kernel 5.15
+            integration_dir: ./integration/container ./integration/build ./integration/system
     with:
       template: ${{ matrix.template }}
+      integration_dir: ${{ matrix.integration_dir }}