CI: Configure additional disk when available

It seems that on some nodepool providers (rax for sure),
we get 40G boot disk and 80G additional disk, while
on others we get 80G boot disk only.

Included fix from I06e262cd48d33ccfc0634589c82dcac80dff51af

Change-Id: I179c41032239f5f0ce6055c79295b32c33fe67a5
(cherry picked from commit a0d758019a)

tests/playbooks/pre.yml

@@ -20,6 +20,76 @@
         path: "{{ kolla_build_logs_dir }}"
         state: directory
 
+    # On RAX hosts, we have a small root partition and a large,
+    # unallocated ephemeral device attached at /dev/xvde
+    - name: Set ephemeral device if /dev/xvde exists
+      when: ansible_devices["xvde"] is defined
+      set_fact:
+        ephemeral_device: "/dev/xvde"
+
+    # On other providers, we have a device called "ephemeral0".
+    - name: Set ephemeral device by label
+      when: ephemeral_device is undefined
+      block:
+        - name: Get ephemeral0 device node
+          command: /sbin/blkid -L ephemeral0
+          register: ephemeral0
+          # rc !=0 is expected
+          failed_when: False
+          changed_when: False
+
+        - name: Set ephemeral device if LABEL exists
+          when: "ephemeral0.rc == 0"
+          set_fact:
+            ephemeral_device: "{{ ephemeral0.stdout }}"
+
+    - name: Configure additional disk (if available)
+      become: true
+      when: ephemeral_device is defined
+      block:
+        - name: Ensure ephemeral device is unmounted
+          ansible.posix.mount:
+            name: "{{ ephemeral_device }}"
+            state: "{{ item }}"
+          loop:
+            - unmounted
+            - absent
+
+        - name: Get existing partitions
+          community.general.parted:
+            device: "{{ ephemeral_device }}"
+            unit: MiB
+            state: info
+          register: ephemeral_partitions
+
+        - name: Remove any existing partitions
+          community.general.parted:
+            device: "{{ ephemeral_device }}"
+            number: "{{ item.num }}"
+            state: absent
+          loop: "{{ ephemeral_partitions.partitions }}"
+
+        - name: Create filesystem on additional partition
+          community.general.filesystem:
+            fstype: ext4
+            dev: "{{ ephemeral_device }}"
+            opts: "-L kolla"
+
+        - name: Ensure /var/lib/docker mountpoint is created
+          ansible.builtin.file:
+            path: "/var/lib/docker"
+            owner: root
+            group: root
+            state: directory
+            mode: 0755
+
+        - name: Mount additional filesystem
+          ansible.posix.mount:
+            path: "/var/lib/docker"
+            src: "LABEL=kolla"
+            fstype: ext4
+            state: mounted
+
     - name: Install Python3 pip and setuptools
       package:
         name: