FEAT(tekton): add OCI manifest list support for Image Updater

- Update buildah task to create OCI manifest list format
- Push images with both :latest and specific tags
- Update all pipelines to use new IMAGE/TAG parameters
- Enable ArgoCD Image Updater digest detection

tekton/ci-cd/manifests/pipelines/fastapi-pipeline.yaml

@@ -47,7 +47,9 @@ spec:
         - clone
       params:
         - name: IMAGE
-          value: zot0213.kro.kr/$(params.app-name):$(params.git-revision)
+          value: zot0213.kro.kr/$(params.app-name)
+        - name: TAG
+          value: $(params.git-revision)
         - name: DOCKERFILE
           value: ./Dockerfile
         - name: CONTEXT

tekton/ci-cd/manifests/pipelines/nextjs-pipeline.yaml

@@ -51,7 +51,9 @@ spec:
         - clone
       params:
         - name: IMAGE
-          value: zot0213.kro.kr/$(params.app-name):$(params.git-revision)
+          value: zot0213.kro.kr/$(params.app-name)
+        - name: TAG
+          value: $(params.git-revision)
         - name: DOCKERFILE
           value: ./Dockerfile
         - name: CONTEXT

tekton/ci-cd/manifests/pipelines/python-pipeline.yaml

@@ -47,7 +47,9 @@ spec:
         - clone
       params:
         - name: IMAGE
-          value: zot0213.kro.kr/$(params.app-name):$(params.git-revision)
+          value: zot0213.kro.kr/$(params.app-name)
+        - name: TAG
+          value: $(params.git-revision)
         - name: DOCKERFILE
           value: ./Dockerfile
         - name: CONTEXT

tekton/ci-cd/manifests/tasks/buildah-build-push.yaml

@@ -4,11 +4,15 @@ metadata:
   name: buildah-build-push
   namespace: tekton-pipelines
 spec:
-  description: Build container image with Buildah and push to registry
+  description: Build container image with Buildah and push as OCI manifest list
   params:
     - name: IMAGE
-      description: Full image reference (registry/repo:tag)
+      description: Image reference without tag (registry/repo)
       type: string
+    - name: TAG
+      description: Image tag (e.g., commit SHA or branch)
+      type: string
+      default: latest
     - name: DOCKERFILE
       description: Path to Dockerfile
       type: string
@@ -31,7 +35,7 @@ spec:
     - name: IMAGE_DIGEST
       description: Digest of built image
     - name: IMAGE_URL
-      description: Full URL of pushed image
+      description: Full URL of pushed image with digest
   steps:
     - name: build-and-push
       image: quay.io/buildah/stable:v1.33
@@ -45,7 +49,9 @@ spec:
         #!/usr/bin/env bash
         set -ex
 
-        REGISTRY=$(echo "$(params.IMAGE)" | cut -d'/' -f1)
+        IMAGE="$(params.IMAGE)"
+        TAG="$(params.TAG)"
+        REGISTRY=$(echo "$IMAGE" | cut -d'/' -f1)
         DOCKER_CONFIG="$(workspaces.dockerconfig.path)/.dockerconfigjson"
 
         # Login to registry
@@ -61,11 +67,24 @@ spec:
           [ -n "$line" ] && BUILD_ARGS_FLAGS="$BUILD_ARGS_FLAGS --build-arg $line"
         done <<< "$BUILD_ARGS"
 
-        # Build and push
-        buildah bud --platform linux/arm64 --format docker \
-          -f $(params.DOCKERFILE) -t $(params.IMAGE) $BUILD_ARGS_FLAGS $(params.CONTEXT)
-        buildah push --digestfile /tmp/image-digest $(params.IMAGE)
+        # Build OCI image
+        buildah bud --platform linux/arm64 --format oci \
+          -f $(params.DOCKERFILE) -t localhost/build:local $BUILD_ARGS_FLAGS $(params.CONTEXT)
+
+        # Create and push manifest list with :latest tag
+        buildah manifest create ${IMAGE}:latest
+        buildah manifest add ${IMAGE}:latest localhost/build:local
+        buildah manifest push --all --digestfile /tmp/image-digest \
+          ${IMAGE}:latest docker://${IMAGE}:latest
+
+        # Also push with specific tag if not 'latest'
+        if [ "$TAG" != "latest" ]; then
+          buildah manifest create ${IMAGE}:${TAG}
+          buildah manifest add ${IMAGE}:${TAG} localhost/build:local
+          buildah manifest push --all ${IMAGE}:${TAG} docker://${IMAGE}:${TAG}
+        fi
 
         # Output results
-        cat /tmp/image-digest | tee $(results.IMAGE_DIGEST.path)
-        echo -n "$(params.IMAGE)" | tee $(results.IMAGE_URL.path)
+        DIGEST=$(cat /tmp/image-digest)
+        echo -n "$DIGEST" | tee $(results.IMAGE_DIGEST.path)
+        echo -n "${IMAGE}:latest@${DIGEST}" | tee $(results.IMAGE_URL.path)