try this out?

Author: owenjones

etc/kayobe/environments/ci-builder/stackhpc-ci.yml

@@ -109,6 +109,13 @@ ipa_build_images: true
 ipa_build_dib_env_extra:
   DISTRO_NAME: "{{ ipa_ci_builder_distribution | default('ubuntu') }}"
   DIB_RELEASE: "{{ ipa_ci_builder_release | default('noble') }}"
+  DIB_CONTAINERFILE_BUILDOPTS: >-
+    {% if os_distribution == 'rocky' and os_release == '10' %}
+      --build-arg=ROCKY_USE_CUSTOM_DNF_MIRRORS=true
+      --build-arg=ROCKY_CUSTOM_DNF_MIRROR_URLS={{ [stackhpc_repo_rocky_10_baseos_url, stackhpc_repo_rocky_10_appstream_url, stackhpc_repo_rocky_10_stackhpc_extras_url] | join(',') }}
+    {% endif %}
+  # Ensure upstream repofiles are re-enabled after image build, otherwise `yum.repos.d` is left empty
+  DIB_ROCKY_CONTAINER_STACKHPC_RESTORE_UPSTREAM_REPOFILES: true
 
 # Ensure Ark repos are disabled during CI runs, this is due to
 # builder being a member of the 'overcloud' group for IPA builds.