Add beaker job on CentOS8

This patch introduces beaker job on CentOS8, so that we can replace
CentOS7 by CentOS8 completely.

Change-Id: Iafcb5446768b05f9d6517e4dc899268b30e1bcde

zuul.d/base.yaml

@@ -185,6 +185,15 @@
       nodepool_type: centos7
       puppet_gem_version: 5.5
 
+- job:
+    name: puppet-openstack-beaker-centos-8
+    parent: puppet-openstack-beaker-run-base
+    nodeset: centos-8
+    voting: false
+    vars:
+      nodepool_type: centos7
+      puppet_gem_version: 5.5
+
 - job:
     name: puppet-openstack-beaker-ubuntu-bionic
     parent: puppet-openstack-beaker-run-base

zuul.d/beaker.yaml

@@ -3,6 +3,7 @@
     check:
       jobs:
         - puppet-openstack-beaker-centos-7
+        - puppet-openstack-beaker-centos-8
         - puppet-openstack-beaker-ubuntu-bionic
     gate:
       jobs:
@@ -30,6 +31,29 @@
       nodepool_type: centos7
       puppet_gem_version: 5.5.0
 
+- job:
+    name: puppet-openstack-libraries-puppet-beaker-rspec-centos-8
+    parent: puppet-openstack-integration-base
+    pre-run: playbooks/prepare-node-beaker.yaml
+    post-run: playbooks/upload-logs.yaml
+    run: playbooks/run-libraries-beaker-tests.yaml
+    timeout: 3600
+    nodeset: centos-8
+    voting: false
+    irrelevant-files:
+      - ^.*\.md$
+      - ^.*\.rst$
+      - ^doc/.*$
+      - ^etc/.*$
+      - ^metadata.json$
+      - ^releasenotes/.*$
+      - ^test-requirements.txt$
+      - ^LICENSE$
+      - ^.gitignore$
+    vars:
+      nodepool_type: centos8
+      puppet_gem_version: 5.5.0
+
 - job:
     name: puppet-openstack-libraries-puppet-beaker-rspec-ubuntu-bionic
     parent: puppet-openstack-integration-base

zuul.d/layout.yaml

@@ -35,6 +35,7 @@
         - puppet-openstack-libraries-puppet-unit-6.11-ubuntu-bionic
         - puppet-openstack-libraries-puppet-unit-latest-ubuntu-bionic
         - puppet-openstack-libraries-puppet-beaker-rspec-centos-7
+        - puppet-openstack-libraries-puppet-beaker-rspec-centos-8
         - puppet-openstack-libraries-puppet-beaker-rspec-ubuntu-bionic
     gate:
       jobs: