diff --git a/images/magnum/Dockerfile b/images/magnum/Dockerfile
index 4eded29..5ab0b72 100644
--- a/images/magnum/Dockerfile
+++ b/images/magnum/Dockerfile
@@ -1,9 +1,10 @@
 # SPDX-License-Identifier: Apache-2.0
 # Atmosphere-Rebuild-Time: 2024-06-26T17:38:39Z
 
+ARG REGISTRY
 ARG RELEASE
 
-FROM harbor.atmosphere.dev/library/ubuntu:${RELEASE} AS helm
+FROM ${REGISTRY}/ubuntu:${RELEASE} AS helm
 ARG TARGETOS
 ARG TARGETARCH
 ARG HELM_VERSION=3.14.0
@@ -11,7 +12,7 @@
 RUN tar -xzf /helm.tar.gz
 RUN mv /${TARGETOS}-${TARGETARCH}/helm /usr/bin/helm
 
-FROM harbor.atmosphere.dev/library/openstack-venv-builder:${RELEASE} AS build
+FROM ${REGISTRY}/openstack-venv-builder:${RELEASE} AS build
 ARG MAGNUM_GIT_REF=2045ffb5ccbfb7873228eba9a6cecc1f65f4ab3f
 ADD --keep-git-dir=true https://opendev.org/openstack/magnum.git#${MAGNUM_GIT_REF} /src/magnum
 RUN git -C /src/magnum fetch --unshallow
@@ -25,7 +26,7 @@
         magnum-cluster-api==0.24.2
 EOF
 
-FROM harbor.atmosphere.dev/library/openstack-python-runtime:${RELEASE}
+FROM ${REGISTRY}/openstack-python-runtime:${RELEASE}
 RUN <<EOF bash -xe
 apt-get update -qq
 apt-get install -qq -y --no-install-recommends \