CI: Build aarch64 images on x86

Since aarch64 OpenDev nodes currently have issues
that cause builds to time out (and we can't extend
over 3 hours since that's OpenDev maximum).

Change-Id: I20d8b7b6de007866f73c41272682f4532987c9e7

Author: mnasiadka

.zuul.d/debian.yaml

@@ -49,8 +49,11 @@
 - job:
     name: kolla-build-debian-aarch64
     parent: kolla-build-debian
-    nodeset: kolla-debian-bookworm-aarch64
+    # NOTE(mnasiadka): Switch to aarch64 nodeset when nodes are fixed
+    nodeset: kolla-debian-bookworm
     voting: false
+    vars:
+      base_arch: aarch64
 
 - job:
     name: kolla-publish-debian-dockerhub

tests/playbooks/pre.yml

@@ -201,3 +201,9 @@
           become: true
       when:
         - container_engine == "podman"
+
+    - name: Run multiarch/qemu-user-static image to support cross-arch build
+      command:
+        cmd: "{{ container_engine }} run --rm --privileged multiarch/qemu-user-static --reset -p yes"
+      become: true
+      when: ansible_facts.architecture != (base_arch | default('x86_64'))

tests/playbooks/run.yml

@@ -10,6 +10,7 @@
         logs_dir: "{{ kolla_build_logs_dir }}"
         quiet: true
         base: "{{ base_distro }}"
+        base_arch: "{{ base_arch | default('x86_64') }}"
         engine: "{{ container_engine }}"
         template_override: /etc/kolla/template_overrides.j2
         # NOTE(yoctozepto): to avoid issues with IPv6 not enabled in the docker daemon