Add install zookeeper role; use for nodepool-builder testing

This adds a simple role to install Zookeeper.

Add an option to nodepool-base to use this role to install Zookeeper.

Use this in the nodepool-builder gate testing where we are just
validating that the nodepool-builder container starts and is ready to
accept connections.  It needs a zookeeper to talk to, even though it
is not going to do anything.

Change-Id: I4ae89a51e454be4ee53ad4e04407162aaa8d9f9a

playbooks/roles/install-zookeeper/README.rst

@@ -0,0 +1,4 @@
+An ansible role to install Zookeeper
+
+**Role Variables**
+

playbooks/roles/install-zookeeper/tasks/main.yaml

@@ -0,0 +1,11 @@
+- name: Install zookeeper
+  package:
+    name:
+      - zookeeper
+      - zookeeperd
+    state: present
+
+- name: Start zookeeper service
+  service:
+    name: zookeeper
+    state: started

playbooks/roles/nodepool-base/README.rst

@@ -1,3 +1,10 @@
 nodepool base setup
 
 **Role Variables**
+
+.. zuul:rolevar:: nodepool_base_install_zookeeper
+
+   Install zookeeper to the node.  This is not expected to be used in
+   production, where the nodes would connect to an externally
+   configured zookeeper instance.  It can be useful for basic loopback
+   tests in the gate, however.

playbooks/roles/nodepool-base/defaults/main.yaml

@@ -0,0 +1 @@
+nodepool_base_install_zookeeper: False

playbooks/roles/nodepool-base/tasks/main.yaml

@@ -11,6 +11,11 @@
     create_home: yes
     shell: /bin/bash
 
+- name: Install zookeeper
+  include_role:
+    name: install-zookeeper
+  when: nodepool_base_install_zookeeper
+
 # NOTE(ianw) : A note on testing; we have some configurations for
 # system-config-run-nodepool test hosts committed to project-config.
 # Since this is a protected repo we can't speculatively test, which is

playbooks/zuul/run-base.yaml

@@ -92,6 +92,7 @@
         - host_vars/mirror-update01.opendev.org.yaml
         - host_vars/backup-test01.opendev.org.yaml
         - host_vars/backup-test02.opendev.org.yaml
+        - host_vars/nb01-test.opendev.org.yaml
     - name: Display group membership
       command: ansible localhost -m debug -a 'var=groups'
     - name: Run base.yaml

playbooks/zuul/templates/host_vars/nb01-test.opendev.org.yaml.j2

@@ -0,0 +1 @@
+nodepool_base_install_zookeeper: True