ci: Create a separate image for fluster

Move the fluster setup into it's own image.

It's only one job using it and this allows us to make
the build image used for the rest of the jobs smaller.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/7455>

.gitlab-ci.yml

@@ -135,6 +135,16 @@ trigger:
     FDO_DISTRIBUTION_TAG: "$FEDORA_TAG-$GST_UPSTREAM_BRANCH"
     FDO_DISTRIBUTION_EXEC: 'GIT_BRANCH=$CI_COMMIT_REF_NAME GIT_URL=$CI_REPOSITORY_URL bash ci/docker/fedora/prepare.sh'
 
+.fedora fluster image:
+  variables:
+    CCACHE_DIR: !reference [".fedora image", "variables", CCACHE_DIR]
+    FDO_DISTRIBUTION_VERSION: !reference [".fedora image", "variables", FDO_DISTRIBUTION_VERSION]
+    FDO_REPO_SUFFIX: !reference [".fedora image", "variables", FDO_REPO_SUFFIX]
+    FDO_DISTRIBUTION_TAG: "fluster-$FEDORA_TAG-$GST_UPSTREAM_BRANCH"
+    FDO_DISTRIBUTION_EXEC: "bash ./ci/docker/fedora/virtme-fluster-setup.sh"
+    # Base the fluster image on top of the main fedora build image
+    FDO_BASE_IMAGE: "$CI_REGISTRY_IMAGE/$FDO_REPO_SUFFIX:$FEDORA_TAG-$GST_UPSTREAM_BRANCH"
+
 fedora amd64 docker:
   extends:
     - '.fedora image'
@@ -145,6 +155,16 @@ fedora amd64 docker:
   # (which has faster network connectivity to the registry).
   tags: [ 'placeholder-job' ]
 
+fedora amd64 docker fluster:
+  extends:
+    - '.fedora fluster image'
+    - '.fdo.container-build@fedora'
+  stage: 'preparation'
+  needs: ["fedora amd64 docker"]
+  # Note: assumption is that placeholder jobs run on a packet runner
+  # (which has faster network connectivity to the registry).
+  tags: [ 'placeholder-job' ]
+
 # Build a toolbox specific image to workaround ci-templates
 fedora amd64 toolbox:
   image: quay.io/freedesktop.org/ci-templates:container-build-base-2024-01-31.0
@@ -850,7 +870,9 @@ gstreamer-full-minimal static build:
 
 # v4l2-stateless-decoders tests
 fluster v4l2-stateless on visl:
-  extends: 'gstreamer-full static build'
+  extends:
+    - '.fedora fluster image'
+    - '.fdo.suffixed-image@fedora'
   stage: 'test'
   variables:
     BUILD_GST_DEBUG: '-Dgstreamer:gst_debug=false'

ci/docker/fedora/prepare.sh

@@ -10,6 +10,4 @@ git config --global user.name "Gstbuild Runner"
 
 bash ./ci/scripts/install-rust.sh
 
-bash ./ci/docker/fedora/virtme-fluster-setup.sh
-
 bash ./ci/scripts/create-subprojects-cache.sh