diff --git a/docker/refstack/Dockerfile b/docker/refstack/Dockerfile
index d8d0ef0945..fc3e73787f 100644
--- a/docker/refstack/Dockerfile
+++ b/docker/refstack/Dockerfile
@@ -31,7 +31,11 @@ RUN apt-get update \
   && apt-get clean \
   && rm -rf /var/lib/apt/lists/*
 
-RUN git clone https://opendev.org/openinfra/refstack /tmp/src
+# Refstack uses openstack constraints (it probably shouldn't) in CI
+# unittesting. Install with constraints here to ensure we're installing
+# what is in theory tested.
+RUN git clone https://opendev.org/openinfra/refstack /tmp/src \
+  && curl https://opendev.org/openstack/requirements/raw/branch/master/upper-constraints.txt -o /tmp/src/upper-constraints.txt
 
 RUN assemble