Make mol_config_dir optional; update molecule development doc

The molecule config parameter should be optional, just to give
possibility to create molecule config file that contains all required
parameters.
Also update molecule development document, that would explain in better
way how to start molecule job manually.

Signed-off-by: Daniel Pawlik <[email protected]>

Author: danpawlik

ci/playbooks/molecule-test.yml

@@ -55,5 +55,7 @@
         chdir: "{{ roles_dir }}"
         cmd: >-
           set -o pipefail;
-          molecule -c {{ mol_config_dir }} test --all |
+          molecule
+          {% if mol_config_dir is defined and mol_config_dir %} -c {{ mol_config_dir }} {% endif %}
+          test --all |
           tee {{ ansible_user_dir }}/ci-framework-data/logs/molecule-execution.log

docs/source/development/02_molecule.md

@@ -77,7 +77,6 @@ cifmw_artifacts_basedir: "{{ ansible_user_dir }}/ci-framework-data/artifacts "
 cifmw_installyamls_repos: "{{ ansible_user_dir }}/src/github.com/openstack-k8s-operators/install_yamls"
 nodepool:
   cloud: ""
-roles_dir: /home/$(whoami)/src/github.com/openstack-k8s-operators/ci-framework/roles
 mol_config_dir: /home/$(whoami)/src/github.com/openstack-k8s-operators/ci-framework/.config/molecule/config_local.yml
 cifmw_zuul_target_host: localhost
 EOF
@@ -87,6 +86,7 @@ ansible-galaxy install -r requirements.yml
 # Mock some roles, that are needed for Zuul CI, but not for local deployment
 mkdir -p roles/mirror-info-fork/tasks
 mkdir -p roles/prepare-workspace/tasks
+mkdir -p group_vars
 
 # Execute Ansible to prepare molecule environment
 ansible-playbook -i inventory.yml \
@@ -97,21 +97,35 @@ ansible-playbook -i inventory.yml \
 ### START MOLECULE JOB ###
 ##########################
 
-# Copy molecule job - example: crc_layout
-mkdir -p roles/molecule/default/
-cp -a ./roles/reproducer/molecule/crc_layout/* roles/molecule/default/
+# Execute molecule job
+## Example
+##    role: reproducer, scenario: crc_layout
 
 # It can be done using:
-# - Ansible
+
+### - Ansible - recommended ###
 
 ansible-playbook -i inventory.yml \
+    -e roles_dir="$(pwd)/roles/reproducer" \
     [email protected] \
     ci/playbooks/molecule-test.yml
 
-# - shell steps
-ln -s roles/molecule .
+#### - shell steps ####
 pip3 install -r test-requirements.txt
-molecule -c .config/molecule/config_local.yml test --all
+cd roles/reproducer
+
+# NOTE: Usually it is: config_local.yml. There is also config_podman.yml scenario
+# NOTE: In some cases, when molecule provides all parameters,
+# do not include config file (skip adding '-c' parameter)
+molecule -c ../../.config/molecule/config_local.yml test --all
+
+# or just one scenario
+molecule -c ../../.config/molecule/config_local.yml test -s crc_layout
+
+# Sometimes it is required to force recreate preparation.
+# For example for crc_layout scenario
+cd roles/reproducer
+molecule prepare --force -s crc_layout
 ```
 
 ### SSH to controller-0 - molecule VM