Run jobs on bionic instead of xenial

Migrate to the latest Ubuntu LTS release 18.04 aka Bionic.  See [0] for
the big picture.

Also test running tox jobs on Bionic.

[0] https://etherpad.openstack.org/p/devstack-bionic

Change-Id: I96e7b8d17bc1e92716c04fdcf362c2adb08a2212

zuul.d/jobs.yaml

@@ -10,7 +10,7 @@
 - job:
     name: kolla-ansible-ubuntu-source
     parent: kolla-ansible-base
-    nodeset: kolla-ansible-xenial
+    nodeset: kolla-ansible-bionic
     vars:
       base_distro: ubuntu
       install_type: source
@@ -36,7 +36,7 @@
 - job:
     name: kolla-ansible-ubuntu-binary
     parent: kolla-ansible-base
-    nodeset: kolla-ansible-xenial
+    nodeset: kolla-ansible-bionic
     voting: false
     vars:
       base_distro: ubuntu
@@ -54,7 +54,7 @@
 - job:
     name: kolla-ansible-ubuntu-source-ceph
     parent: kolla-ansible-base
-    nodeset: kolla-ansible-xenial-multi
+    nodeset: kolla-ansible-bionic-multi
     voting: false
     vars:
       base_distro: ubuntu
@@ -105,7 +105,7 @@
 - job:
     name: kolla-ansible-ubuntu-source-cinder-lvm
     parent: kolla-ansible-base
-    nodeset: kolla-ansible-xenial-multi
+    nodeset: kolla-ansible-bionic-multi
     voting: false
     vars:
       base_distro: ubuntu
@@ -133,7 +133,7 @@
 - job:
     name: kolla-ansible-ubuntu-source-zun
     parent: kolla-ansible-base
-    nodeset: kolla-ansible-xenial
+    nodeset: kolla-ansible-bionic
     voting: false
     vars:
       base_distro: ubuntu

zuul.d/nodesets.yaml

@@ -11,6 +11,12 @@
       - name: primary
         label: ubuntu-xenial
 
+- nodeset:
+    name: kolla-ansible-bionic
+    nodes:
+      - name: primary
+        label: ubuntu-bionic
+
 - nodeset:
     name: kolla-ansible-xenial-multi
     nodes:
@@ -29,6 +35,24 @@
           - secondary1
           - secondary2
 
+- nodeset:
+    name: kolla-ansible-bionic-multi
+    nodes:
+      - name: primary
+        label: ubuntu-bionic
+      - name: secondary1
+        label: ubuntu-bionic
+      - name: secondary2
+        label: ubuntu-bionic
+    groups:
+      - name: switch
+        nodes:
+          - primary
+      - name: peers
+        nodes:
+          - secondary1
+          - secondary2
+
 - nodeset:
     name: kolla-ansible-centos-multi
     nodes: