Also build sibling container images

These are tagged as sibling images, and use openstacksdk/dib from Zuul
checkouts.  Since we don't want them released to dockerhub, keep the
job separate.

Change-Id: Ifa151e3fb91a8705872989f7d70755e21bb5bf0b

.zuul.yaml

@@ -183,10 +183,37 @@
         secret: nodepool-dockerhub
         pass-to-parent: true
 
+# NOTE(ianw) : kept separate as these aren't intended to be released
+- job:
+    name: nodepool-build-image-siblings
+    parent: opendev-build-docker-image
+    description: Build docker images, with required projects as sibling from source
+    required-projects:
+      - openstack/diskimage-builder
+      - openstack/openstacksdk
+    vars:
+      docker_images:
+        - context: .
+          repository: zuul/nodepool-launcher
+          target: nodepool-launcher
+          tags:
+            - siblings
+          siblings:
+            - opendev.org/openstack/openstacksdk
+        - context: .
+          repository: zuul/nodepool-builder
+          target: nodepool-builder
+          tags:
+            - siblings
+          siblings:
+            - opendev.org/openstack/openstacksdk
+            - opendev.org/openstack/diskimage-builder
+
 - project:
     check:
       jobs:
         - nodepool-build-image
+        - nodepool-build-image-siblings
         - zuul-tox-docs
         - tox-pep8
         - tox-py35:

Dockerfile

@@ -15,6 +15,7 @@
 
 FROM opendevorg/python-builder as builder
 
+ARG ZUUL_SIBLINGS=""
 COPY . /tmp/src
 RUN assemble