ci: add full-node tests (#920)

diff --git a/images/octavia/Earthfile b/images/octavia/Earthfile
index d37ba36..906e325 100644
--- a/images/octavia/Earthfile
+++ b/images/octavia/Earthfile
@@ -1,5 +1,6 @@
 VERSION 0.7
 
+ARG --global REGISTRY=ghcr.io/vexxhost/atmosphere
 ARG --global PROJECT=octavia
 ARG --global RELEASE=2023.2
 ARG --global PROJECT_REF=88d7315a60314e44fcce88ad198ceb3c0c107fe6
@@ -17,5 +18,5 @@
   DO ../+APT_INSTALL \
     --PACKAGES "isc-dhcp-client openssh-client"
   SAVE IMAGE --push \
-    ghcr.io/vexxhost/atmosphere/${PROJECT}:${RELEASE} \
-    ghcr.io/vexxhost/atmosphere/${PROJECT}:${PROJECT_REF}
+    ${REGISTRY}/${PROJECT}:${RELEASE} \
+    ${REGISTRY}/${PROJECT}:${PROJECT_REF}