Add legacy-base job to handle /etc/nodepool

Change-Id: I0c1bbdc84e888e16dfb151f720dd178030360dec

playbooks/legacy/pre.yaml

@@ -0,0 +1,25 @@
+- hosts: all
+  tasks:
+    - name: Create nodepool directory
+      file:
+        path: /etc/nodepool
+        state: directory
+    - name: Create nodepool subnodes file
+      copy:
+        dest: /etc/nodepool/sub_nodes_private
+        content: ""
+    - name: Populate nodepool subnodes file
+      lineinfile:
+        path: /etc/nodepool/sub_nodes_private
+        line: "{{ hostvars[item]['nodepool']['private_ipv4'] }}"
+      with_items: "{{ groups['subnodes'] }}"
+      when: groups['subnodes'] is defined
+    - name: Create nodepool primary file
+      copy:
+        dest: /etc/nodepool/primary_node_private
+        content: "{{ hostvars['primary']['nodepool']['private_ipv4'] }}"
+    - name: Copy ssh keys to nodepool directory
+      command: "cp .ssh/{{ item }} /etc/nodepool/{{ item }}"
+      with_items:
+        - id_rsa
+        - id_rsa.pub

zuul.yaml

@@ -230,6 +230,12 @@
       Check version used by xstatic packages
     run: playbooks/xstatic/check-version
 
+- job:
+    name: legacy-base
+    description: |
+      Base job for autoconverted legacy jobs
+    pre-run: playbooks/legacy/pre
+
 - job:
     name: legacy-dsvm-base
     description: |
@@ -239,6 +245,7 @@
       may be used by jobs which have been automatically converted as
       part of the migration to Zuul v3.
     nodeset: devstack-single-node
+    pre-run: playbooks/legacy/pre
     required-projects:
       - openstack-dev/devstack
       - openstack-infra/devstack-gate