diff --git a/build.gradle b/build.gradle
index d198080..053fcc2 100644
--- a/build.gradle
+++ b/build.gradle
@@ -31,6 +31,19 @@
             : 'candidate'
 }
 
+# Pull XOS images that exist on Docker Hub.
+# All images will get rebuilt during the buildImages step, but may at least
+# be able to use some intermediate images.
+task fetch(type: Exec) {
+  executable = "ansible-playbook"
+  args = [
+    "--extra-vars", "@../../build/genconfig/config.yml",
+    "--extra-vars", "build_docker_tag="+targetTag,
+    "--extra-vars", "cord_dir=../..",
+    "pull-xos-playbook.yml" ]
+}
+
+# Build all XOS images from source.
 task buildImages(type: Exec) {
   executable = "ansible-playbook"
   args = [
@@ -40,6 +53,7 @@
     "build-xos-playbook.yml" ]
 }
 
+# Publish XOS images to the head node registry.
 task publish(type: Exec) {
   executable = "ansible-playbook"
   args = [ "-i", "../../build/genconfig/cord-inv",