Add base-minimal job

This is required by zuul-jobs for its testing.  We could put it
only in the Zuul tenant, but we would need to duplicate the secret,
so this is lazier.  It shouldn't hurt to have it in all the tenants.
We can set allowed-projects so that only zuul-jobs can use it in
order to avoid accidental use and confusion.

Change-Id: I8966737c580628b4fa097e32594c8a4e99926147

playbooks/base-minimal/README.rst

@@ -0,0 +1,8 @@
+base-minimal
+------------
+
+These playbooks are used to select a minimal subset of the roles included in
+the base playbooks.
+
+It will do nothing else than what is explicitely necessary for any job to run
+properly.

playbooks/base-minimal/post-logs.yaml

@@ -0,0 +1,10 @@
+- hosts: localhost
+  roles:
+    - role: add-fileserver
+      fileserver: "{{ site_logs }}"
+    - role: ara-report
+
+- hosts: "{{ site_logs.fqdn }}"
+  roles:
+    - role: upload-logs
+      zuul_log_url: "http://logs.openstack.org"

playbooks/base-minimal/post.yaml

@@ -0,0 +1,11 @@
+- hosts: all
+  roles:
+    - fetch-output
+    - merge-output-to-logs
+
+- hosts: all
+  # NOTE(pabelanger): We ignore_errors for the following tasks as not to fail
+  # successful jobs.
+  ignore_errors: yes
+  roles:
+    - remove-build-sshkey

playbooks/base-minimal/pre.yaml

@@ -0,0 +1,9 @@
+- hosts: all
+  roles:
+    - add-build-sshkey
+    - start-zuul-console
+    - log-inventory
+    - role: validate-host
+      # TODO(mordred) When we have site-local variables, these should go there
+      zuul_traceroute_host: opendev.org
+      zuul_image_manifest: /etc/dib-builddate.txt

zuul.d/jobs.yaml

@@ -190,13 +190,40 @@
     vars:
       ara_report_type: database
       ara_report_path: ara-report
-    nodeset:
-      nodes:
-        - name: ubuntu-bionic
-          label: ubuntu-bionic
+    nodeset: ubuntu-bionic
     secrets:
       - site_logs
 
+- job:
+    name: base-minimal
+    parent: null
+    abstract: true
+    description: |
+      A subset of what the 'base' job provides: the absolute minimum considered
+      required to run for any one job.
+      It doesn't set up cached git repositories, will not set up mirrors,
+      doesn't validate the node, etc.
+      It is meant to be used, amongst other things, to test roles and
+      playbooks that would otherwise be included by default as part of the
+      'base' job.
+      These tasks, if required, can be included by the dependant jobs
+      themselves on a need basis.
+    pre-run: playbooks/base-minimal/pre.yaml
+    post-run:
+      - playbooks/base-minimal/post.yaml
+      - playbooks/base-minimal/post-logs.yaml
+    roles:
+      - zuul: zuul/zuul-jobs
+    vars:
+      ara_report_type: database
+      ara_report_path: ara-report
+    timeout: 1800
+    post-timeout: 1800
+    nodeset: ubuntu-bionic
+    secrets:
+      - site_logs
+    allowed-projects: zuul/zuul-jobs
+
 - secret:
     name: opendev-intermediate-registry
     data: