Drop Ubuntu Bionic and Older testing

This comes about because OpenDev's Zuul deployment is using Ansible 11
by default now. Ansible 11 doesn't support python older than python3.8.
Bionic has python3.6 on it so python3.6 tests on Bionic fail hard with
Ansible 11. Let's drop the python3.6 test entirely as a result.

Then we've also recently cleaned out the Xenial (for x86-64 and arm64)
mirror content as OpenDev doesn't have any Xenial test nodes any longer.
This broke DIB jobs that build Xenial and Bionic ARM64 images.
Considering Bionic doesn't work with Ansible 11 OpenDev expects to clean
up those test images in the near future too. Let's get ahead of that
cleanup in DIB and drop all testing for Xenial and Bionic.

Note we keep the old nodepool based functional jobs around for now as
projects like glean still use them. We should clean those jobs up in a
separate effort.

Change-Id: Id3f5d290aed503d70c7c06bf4a1477169b2a84c6
Signed-off-by: Clark Boylan <clark.boylan@gmail.com>

.zuul.d/jobs.yaml

@@ -37,7 +37,6 @@
         # checksum mismatches; see
         #  https://bugzilla.suse.com/show_bug.cgi?id=1202041
         # - opensuse/build-succeeds
-        - ubuntu/bionic-build-succeeds
         - ubuntu/focal-build-succeeds
         - ubuntu/jammy-build-succeeds
         - ubuntu/noble-build-succeeds
@@ -52,7 +51,6 @@
     parent: dib-functests-base
     vars:
       dib_functests:
-        - ubuntu-minimal/bionic-arm64-build-succeeds
         - ubuntu-minimal/focal-arm64-build-succeeds
         - ubuntu-minimal/jammy-arm64-build-succeeds
         - ubuntu-minimal/noble-arm64-build-succeeds
@@ -376,22 +374,6 @@
           DIB_DISABLE_APT_CLEANUP: '1'
           DIB_DEBOOTSTRAP_EXTRA_ARGS: '--no-check-gpg'
 
-- job:
-    name: dib-devstack-functional-openstack-ubuntu-xenial-src
-    description: |
-      Test building and booting an Ubuntu xenial image with devstack
-      and OpenStack
-    parent: dib-devstack-functional-src-base
-    vars:
-      diskimage:
-        base_element: ubuntu-minimal
-        release: 'xenial'
-        env-vars:
-          DIB_APT_LOCAL_CACHE: '0'
-          DIB_DISABLE_APT_CLEANUP: '1'
-          DIB_DEBOOTSTRAP_EXTRA_ARGS: '--no-check-gpg'
-          DIB_DISTRIBUTION_MIRROR: "http://{{ zuul_site_mirror_fqdn }}/ubuntu"
-
 - job:
     name: dib-nodepool-functional-openstack-ubuntu-bionic-src
     description: |
@@ -408,22 +390,6 @@
           DIB_DISABLE_APT_CLEANUP: '1'
           DIB_DEBOOTSTRAP_EXTRA_ARGS: '--no-check-gpg'
 
-- job:
-    name: dib-devstack-functional-openstack-ubuntu-bionic-src
-    description: |
-      Test building and booting an Ubuntu bionic image with devstack
-      and OpenStack
-    parent: dib-devstack-functional-src-base
-    vars:
-      diskimage:
-        base_element: ubuntu-minimal
-        release: 'bionic'
-        env-vars:
-          DIB_APT_LOCAL_CACHE: '0'
-          DIB_DISABLE_APT_CLEANUP: '1'
-          DIB_DEBOOTSTRAP_EXTRA_ARGS: '--no-check-gpg'
-          DIB_DISTRIBUTION_MIRROR: "http://{{ zuul_site_mirror_fqdn }}/ubuntu"
-
 - job:
     name: dib-nodepool-functional-openstack-ubuntu-focal-src
     description: |

.zuul.d/project.yaml

@@ -6,11 +6,6 @@
     check:
       jobs:
         - openstack-tox-linters
-        - tox-py36:
-            nodeset:
-              nodes:
-                - name: ubuntu-bionic
-                  label: ubuntu-bionic
         - tox-py38:
             nodeset:
               nodes:
@@ -55,8 +50,6 @@
             voting: false
         - dib-devstack-functional-openstack-rockylinux-10-containerfile-src:
             voting: false
-        - dib-devstack-functional-openstack-ubuntu-xenial-src
-        - dib-devstack-functional-openstack-ubuntu-bionic-src
         - dib-devstack-functional-openstack-ubuntu-focal-src
         - dib-devstack-functional-openstack-ubuntu-jammy-src
         - dib-devstack-functional-openstack-ubuntu-noble-src
@@ -79,11 +72,6 @@
     gate:
       jobs:
         - openstack-tox-linters
-        - tox-py36:
-            nodeset:
-              nodes:
-                - name: ubuntu-bionic
-                  label: ubuntu-bionic
         - tox-py38:
             nodeset:
               nodes:
@@ -112,8 +100,6 @@
         - opendev-buildset-registry
         - nodepool-build-image-siblings
         - dib-devstack-functional-openstack-centos-9-stream-src
-        - dib-devstack-functional-openstack-ubuntu-xenial-src
-        - dib-devstack-functional-openstack-ubuntu-bionic-src
         - dib-devstack-functional-openstack-ubuntu-focal-src
         - dib-devstack-functional-openstack-ubuntu-jammy-src
         - dib-devstack-functional-openstack-ubuntu-noble-src

tests/run_functests.sh

@@ -52,8 +52,10 @@ DEFAULT_SKIP_TESTS=(
     # This job is a bit unreliable, even if we get mirroring
     debian-minimal/testing-build-succeeds
 
-    # Replaced by bionic
+    # Old and no longer supported in a default test env
     ubuntu-minimal/trusty-build-succeeds
+    ubuntu-minimal/xenial-build-succeeds
+    ubuntu-minimal/bionic-build-succeeds
 )
 
 # The default output formats (specified to disk-image-create's "-t"