Fix v6 CI job - Return it to normal non-voting status

* Fixes the IPv6 job by utilizing HOST_IPV6 instead of
  SERVICE_IPV6, as Devstack now automatically wraps
  SERVICE_IPV6 with brackets as if it is for a URL.
* Locks ipv6 job to bios mode. Ubuntu Focal OVMF/EDK2 does not
  support IPv6 PXE boot by default.
* Split from Devstack in terms of IP usage, since full explicit
  V6 usage is not a thing anymore. 4+6 is the default in devstack
  and regardless of what we set on the job we see both now used.
  So we delineate apart our usage for our own sanity.
* Reduce VM Interface count for IPv6 in an attempt to eliminate
  in-kernel routing confusion by two interfaces on the same physical
  network.
* Set IPv6 mode to dhcpv6-stateless due to fun issues in dhcp clients.
  When we move to UEFI, this will need to be changed to stateful as
  stateless is not supported in general by OVMF/E2DK.

Once the job has run in normal non-voting for a while, and we
ensure that it seems to be stable, we can make it voting again.

Change-Id: Ia833bfb64c6c3cc8e48cbe34ed200536652a8adf

devstack/lib/ironic

@@ -500,7 +500,7 @@ else
     # loopback cannot be used for v6 testing.
         IRONIC_HOST_IPV6='fc00::1'
     else
-        IRONIC_HOST_IPV6=$SERVICE_HOST
+        IRONIC_HOST_IPV6=$HOST_IPV6
     fi
     IRONIC_PROVISION_SUBNET_GATEWAY=${IRONIC_PROVISION_SUBNET_GATEWAY:-'fc01::1'}
     IRONIC_PROVISION_SUBNET_SUBNODE_IP=${IRONIC_PROVISION_SUBNET_SUBNODE_IP:-'fc01::2'}
@@ -1342,7 +1342,7 @@ function configure_ironic_rescue_network {
 }
 
 function configure_ironic_provision_network {
-    if [[ "$IP_VERSION" == "6" ]]; then
+    if [[ "$IRONIC_IP_VERSION" == "6" ]]; then
         # NOTE(TheJulia): Ideally we should let this happen
         # with our global address, but iPXE seems to have in
         # consistant behavior in this configuration with devstack.
@@ -1402,9 +1402,11 @@ function configure_ironic_provision_network {
                 --gateway $IRONIC_PROVISION_SUBNET_GATEWAY --network $net_id \
                 --subnet-range $IRONIC_PROVISION_SUBNET_PREFIX -f value -c id)"
         else
+            # NOTE(TheJulia): Consider changing this to stateful to support UEFI once we move
+            # CI to Ubuntu Jammy as it will support v6 and v4 UEFI firmware driven boot ops.
             subnet_id="$(openstack --os-cloud $OS_CLOUD subnet create --ip-version 6 \
-                --ipv6-address-mode dhcpv6-stateful \
-                --ipv6-ra-mode dhcpv6-stateful \
+                --ipv6-address-mode dhcpv6-stateless \
+                --ipv6-ra-mode dhcpv6-stateless \
                 --dns-nameserver 2001:4860:4860::8888 \
                 ${net_segment_id:+--network-segment $net_segment_id} \
                 $IRONIC_PROVISION_PROVIDER_SUBNET_NAME \

zuul.d/ironic-jobs.yaml

@@ -744,8 +744,7 @@
       devstack_localrc:
         IRONIC_AGENT_IMAGE_DOWNLOAD_SOURCE: http
         IPV6_ENABLED: True
-        IP_VERSION: 6
-        SERVICE_IP_VERSION: 6
+        IRONIC_IP_VERSION: 6
         IRONIC_AUTOMATED_CLEAN_ENABLED: False
         IRONIC_ENABLED_BOOT_INTERFACES: ipxe,pxe
         IRONIC_DEFAULT_BOOT_INTERFACE: ipxe
@@ -760,6 +759,7 @@
         IRONIC_USE_LINK_LOCAL: True
         IRONIC_TEMPEST_WHOLE_DISK_IMAGE: True
         IRONIC_VM_EPHEMERAL_DISK: 0
+        IRONIC_VM_INTERFACE_COUNT: 1
         # This will swap and needs to get to tinycore soon.
         IRONIC_VM_SPECS_CPU: 2
         Q_PLUGIN: ml2
@@ -773,6 +773,14 @@
         BUILD_TIMEOUT: 2000
         IRONIC_TEMPEST_BUILD_TIMEOUT: 2000
         IRONIC_PING_TIMEOUT: 1440
+        # TODO(TheJulia): Change this to UEFI once we have Ubuntu Jammy
+        # as it auto-attempts to UEFI boot PXE v4 and PXE v6. Prior just
+        # does IPv4 and we cannot easily edit the nvram to inject just v6.
+        # TODO(TheJulia): The devstack plugin also needs to be changed to
+        # dhcpv6-stateful instead of stateless when this is changed to UEFI
+        # as OVMF/E2DK does not support stateless.
+        IRONIC_BOOT_MODE: bios
+
 
 # NOTE(rpittau): OLD TINYIPA JOBS
 # Those jobs are used by other projects, we leave them here until

zuul.d/project.yaml

@@ -45,6 +45,8 @@
             voting: false
         - ironic-tempest-ipa-wholedisk-bios-ipmi-direct-dib:
             voting: false
+        - ironic-tempest-ipxe-ipv6:
+            voting: false
         - ironic-inspector-tempest-rbac-scope-enforced:
             voting: false
         - bifrost-integration-tinyipa-ubuntu-focal:
@@ -80,8 +82,6 @@
       jobs:
         # TODO(dtantsur): these jobs are useful but currently hopelessly
         # broken. Fix them and bring back to the gate.
-        - ironic-tempest-ipxe-ipv6:
-            voting: false
         - ironic-grenade-multinode-multitenant:
             voting: false
         - ironic-inspector-tempest-discovery-fast-track: