diff --git a/share/spack/gitlab/cloud_pipelines/configs/ci.yaml b/share/spack/gitlab/cloud_pipelines/configs/ci.yaml
index fde9aad3268..3e81461e48d 100644
--- a/share/spack/gitlab/cloud_pipelines/configs/ci.yaml
+++ b/share/spack/gitlab/cloud_pipelines/configs/ci.yaml
@@ -20,7 +20,7 @@ ci:
         - k=$CI_GPG_KEY_ROOT/intermediate_ci_signing_key.gpg; [[ -r $k ]] && spack gpg trust $k
         - k=$CI_GPG_KEY_ROOT/spack_public_key.gpg; [[ -r $k ]] && spack gpg trust $k
       script::
-      - - if [ -n "$SPACK_EXTRA_MIRROR" ]; then spack mirror add local "$SPACK_EXTRA_MIRROR"; fi
+      - - if [ -n "$SPACK_EXTRA_MIRROR" ]; then spack mirror add local "${SPACK_EXTRA_MIRROR}/${SPACK_CI_STACK_NAME}"; fi
         - spack config blame mirrors
       - - spack --color=always --backtrace ci rebuild -j ${SPACK_BUILD_JOBS} --tests > >(tee ${SPACK_ARTIFACTS_ROOT}/user_data/pipeline_out.txt) 2> >(tee ${SPACK_ARTIFACTS_ROOT}/user_data/pipeline_err.txt >&2)
       after_script: