change ipv6 public network cidr on tempest-slow job

Neutron recently enhanced CIDR overlap checks for all the subnets
attached to router including external [1]. This breaks tempest
scenario ipv6 tests which is fixed in tempest by the following
commit [2]. However the fix mentioned in [2] cannot be ported
back to tempest 23.0.0 as rocky is in EM stage.

To fix this, the public IPv6 network CIDR is changed to use
different subnet on the tempest-slow job.

Closes-Bug: #1914037

[1] https://review.opendev.org/q/Id5d8ac09a38c656619f88a6f87b8f384fe4c55a8
[2] https://opendev.org/openstack/tempest/commit/4ad346e6497d4fbad9e379e8ed50730a0b6b55a3

Change-Id: I62a746cc871434e8488b19bc2ef5bbcfcf4f0be6
diff --git a/zuul.d/integrated-gate.yaml b/zuul.d/integrated-gate.yaml
index 27bbf64..9684015 100644
--- a/zuul.d/integrated-gate.yaml
+++ b/zuul.d/integrated-gate.yaml
@@ -294,6 +294,8 @@
         * legacy-tempest-dsvm-neutron-scenario-multinode-lvm-multibackend
         * tempest-scenario-multinode-lvm-multibackend
     timeout: 10800
+    # This job runs on stable/stein onwards.
+    branches: ^(?!stable/(ocata|pike|queens|rocky)).*$
     vars:
       tox_envlist: slow-serial
       devstack_localrc:
@@ -314,6 +316,46 @@
           ENABLE_VOLUME_MULTIATTACH: true
 
 - job:
+    name: tempest-slow
+    parent: tempest-multinode-full
+    description: |
+      This multinode integration job will run all the tests tagged as slow.
+      It enables the lvm multibackend setup to cover few scenario tests.
+      This job will run only slow tests (API or Scenario) serially.
+
+      Former names for this job were:
+        * legacy-tempest-dsvm-neutron-scenario-multinode-lvm-multibackend
+        * tempest-scenario-multinode-lvm-multibackend
+    timeout: 10800
+    branches:
+      - stable/pike
+      - stable/queens
+      - stable/rocky
+    vars:
+      tox_envlist: slow-serial
+      devstack_localrc:
+        CINDER_ENABLED_BACKENDS: lvm:lvmdriver-1,lvm:lvmdriver-2
+        ENABLE_VOLUME_MULTIATTACH: true
+        # to avoid https://bugs.launchpad.net/neutron/+bug/1914037
+        # as we couldn't backport the fix to rocky and older releases
+        IPV6_PUBLIC_RANGE: 2001:db8:0:10::/64
+        IPV6_PUBLIC_NETWORK_GATEWAY: 2001:db8:0:10::2
+        IPV6_ROUTER_GW_IP: 2001:db8:0:10::1
+      devstack_plugins:
+        neutron: https://opendev.org/openstack/neutron
+      devstack_services:
+        neutron-placement: true
+        neutron-qos: true
+      tempest_concurrency: 2
+    group-vars:
+      # NOTE(mriedem): The ENABLE_VOLUME_MULTIATTACH variable is used on both
+      # the controller and subnode prior to Rocky so we have to make sure the
+      # variable is set in both locations.
+      subnode:
+        devstack_localrc:
+          ENABLE_VOLUME_MULTIATTACH: true
+
+- job:
     name: tempest-slow-py3
     parent: tempest-slow
     vars: