Ansible testing using Molecule with Ansible as a verifier

In this tutorial, we will learn how to test framework code written in Ansible using a testing framework known as Molecule. Inside Molecule, we will use Ansible as a verifier, which I could not find anywhere else. Let's do it!

Content

1. Introduction
2. Molecule
3. Molecule Ansible
4. Ansible Ansible Verifier

Ansible — , , , , . , . -.

, . . , , , , .

Molecule — , Ansible. 26 Ansible Molecule Ansible-lint Red Hat Ansible. Red Hat , , .

Molecule , , , .

Molecule TDD- . , , , Molecule.

Molecule

, UNIX.

Molecule :

• Python 2.7 Python 3.5 ( Python 3.7)
• Ansible 2.5 ( Ansible 2.9.6)
• Docker ( )

Pip — Molecule. Python 2.7.9 ( ) Python 3.4 ( ), PIP Python.

Molecule pip:

$ pip3 install molecule

. « Molecule». , Molecule, $ molecule --version.

Ansible Playbooks , , Ansible , .. Ansible , , , , , , , Ansible, , , — , , (, ).

Molecule Ansible

Molecule Ansible:

. Molecule Ansible

Molecules Ansible Galaxy Ansible. Molecule:

$ molecule init role <the_role_name>

. Initiating Ansible

Molecule , , , , , :

$ molecule init scenario -r <the_already_existing_role_name>

, Molecule, Molecule . :

.
├── README.md
├── files/                                                
├── handlers/                                              
├── meta/                                                            
├── tasks/                                                 
├── templates/                                              
├── tests/                                               
├── vars/                                              
└── molecule/
        └── default                        
                ├── molecule.yml                        
                ├── converge.yml                        
                ├── verify.yml                                               
                └── INSTALL.rst

Molecule :

molecule.yml

molecule.yml Molecule, .

---
dependency:
  name: galaxy
  enabled: true # to disable, set to false
driver:
  name: docker
platforms:
  - name: instance
    image: docker.io/pycontribs/centos:7
    pre_build_image: true
provisioner:
  name: ansible
verifier:
  name: ansible

dependency:

, . Ansible Galaxy — , Molecule. — Shell Gilt. dependency true, , enabled false.

driver:

Molecule, . Molecule — Docker, , : AWS, Azure, Google Cloud, Vagrant, Hetzner Cloud . . Molecule .

platforms:

, . , , , , .

provisioner:

Provider — , converge.yml ( ). — Ansible.

verifier:

verifier — , . verify.yml, , ( ) ( ). — Ansible, , : testinfra, goss inspec. testinfra , - UX , Python, testinfra , Ansible , . git issue .

, , — lint . Molevel.yml .

lint:

Lint , Molecule , , , . — yamllint, ansible-lint, flake8 .

scenario:

Molecule. , , . , .

, — , Molecule. , :

scenario:
  create_sequence:
    - dependency
    - create
    - prepare
  check_sequence:
    - dependency
    - cleanup
    - destroy
    - create
    - prepare
    - converge
    - check
    - destroy
  converge_sequence:
    - dependency
    - create
    - prepare
    - converge
  destroy_sequence:
    - dependency
    - cleanup
    - destroy
  test_sequence:
    - dependency
    - lint
    - cleanup
    - destroy
    - syntax
    - create
    - prepare
    - converge
    - idempotence
    - side_effect
    - verify
    - cleanup
    - destroy

, , Molecule, , $ molecule create , create_sequence, $ molecule check check_sequence .

, , , , , , .

Converge.yml

converge.yml, , , . . , $ molecule converge.

verify.yml

verify.yml , . , . , $ molecule verify.

INSTALL.rst

, Molecule .

Ansible Ansible Verifier

, , , Ansible Ansible Molecule.

$ molecule test test_sequence, , , , , .

, , BDD, :

# given phase
$ molecule create

# when phase
$ molecule converge

# then phase
$ molecule verify

, () . , .

— TDD . . , alpha-services, :

• 1. Java-1.8 -.
• 2: /var/log/tomcat, tomcat, tomcat 0755
• 3. , httpd
• 4. template/tomcat/context.xml /etc/tomcat/context.xml

, Molecule :

$ molecule init role alpha-services

, . alpha-services/molecule/default/roles/test_alpha-services:

$ cd alpha-services
$ mkdir -p molecule/default/roles/test_alpha-services

. test_alpha-services

, Ansible ( , , , ). main.yml. yml, , test_. , java test_java.yml.

$ cd molecule/default/roles/test_alpha-services
$ mkdir defaults && touch defaults/main.yml
$ mkdir tasks && touch tasks/main.yml tasks/test_java.yml tasks/test_tomcat.yml tasks/test_httpd.yml tasks/test_aws.yml
$ mkdir vars && touch vars/main.yml

:

alpha-services/
        ├── README.md
        ├── files/                                                
        ├── handlers/                                              
        ├── meta/                                                            
        ├── tasks/                                                 
        ├── templates/                                              
        ├── tests/                                               
        ├── vars/                                              
        └── molecule/
                └── default                        
                        ├── molecule.yml                        
                        ├── converge.yml                        
                        ├── verify.yml                                               
                        ├── INSTALL.rst                       
                        └── roles/    
                              └── test_alpha-services/                        
                                        ├── defaults/                        
                                              └── main.yml                                               
                                        ├── tasks/                        
                                              ├── main.yml 
                                              ├── test_java.yml                        
                                              ├── test_tomcat.yml                        
                                              ├── test_httpd.yml                                               
                                              └── test_aws.yml      
                                        └── vars/                        
                                              └── main.yml

molecule.yml:

---
dependency:
  name: galaxy
  enabled: false
driver:
  name: docker
platforms:
  - name: instance
    image: docker.io/pycontribs/centos:7
    pre_build_image: true
provisioner:
  name: ansible
verifier:
  name: ansible

converge.yml :

---
- name: Converge
  hosts: all
  tasks:
    - name: "Include alpha-services"
      include_role:
        name: "alpha-services"

verify.yaml, :

---
# This is an example playbook to execute Ansible tests.
- name: Verify
  hosts: all
  tasks:
    - name: "Include test_alpha-services"
      include_role:
        name: "test_alpha-services"

GIVEN : $ molecule create .

$ molecule create

--> Test matrix

└── default
    ├── dependency
    ├── create
    └── prepare

--> Scenario: 'default'
--> Action: 'dependency'
Skipping, dependency is disabled.
--> Scenario: 'default'
--> Action: 'create'
--> Sanity checks: 'docker'

    PLAY [Create] ******************************************************************

    TASK [Log into a Docker registry] **********************************************
    skipping: [localhost] => (item=None) 

    TASK [Check presence of custom Dockerfiles] ************************************
    ok: [localhost] => (item=None)
    ok: [localhost]

    TASK [Create Dockerfiles from image names] *************************************
    skipping: [localhost] => (item=None) 

    TASK [Discover local Docker images] ********************************************
    ok: [localhost] => (item=None)
    ok: [localhost]

    TASK [Build an Ansible compatible image (new)] *********************************
    skipping: [localhost] => (item=molecule_local/docker.io/pycontribs/centos:7) 

    TASK [Create docker network(s)] ************************************************

    TASK [Determine the CMD directives] ********************************************
    ok: [localhost] => (item=None)
    ok: [localhost]

    TASK [Create molecule instance(s)] *********************************************
    changed: [localhost] => (item=instance)

    TASK [Wait for instance(s) creation to complete] *******************************
    FAILED - RETRYING: Wait for instance(s) creation to complete (300 retries left).
    changed: [localhost] => (item=None)
    changed: [localhost]

    PLAY RECAP *********************************************************************
    localhost                  : ok=5    changed=2    unreachable=0    failed=0    skipped=4    rescued=0    ignored=0

--> Scenario: 'default'
--> Action: 'prepare'
Skipping, prepare playbook not configured.

WHEN : $ molecule converge , . .

$ molecule converge

--> Test matrix

└── default
    ├── dependency
    ├── create
    ├── prepare
    └── converge

--> Scenario: 'default'
--> Action: 'dependency'
Skipping, dependency is disabled.
--> Scenario: 'default'
--> Action: 'create'
Skipping, instances already created.
--> Scenario: 'default'
--> Action: 'prepare'
Skipping, prepare playbook not configured.
--> Scenario: 'default'
--> Action: 'converge'
--> Sanity checks: 'docker'

    PLAY [Converge] ****************************************************************

    TASK [Gathering Facts] *********************************************************
    ok: [instance]

    TASK [Include alpha-services] **************************************************

    TASK [alpha-services : include java installation tasks] ************************
    included: /Users/chukwudiuzoma/Documents/DevOps/ANSIBLE/MyTutorials/AnsibleTestingWithMolecule/alpha-services/tasks/java.yml for instance

    TASK [alpha-services : Install java] *******************************************
    changed: [instance]

    PLAY RECAP *********************************************************************
    instance                   : ok=3    changed=1    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

.

TDD, , , , .

1. Java-1.8.0 -

---
- name: "java - check Java package status"
  package:
    name: "java-1.8.0"
    state: "installed"
  check_mode: yes
  register: pkg_status

- name: "java - test java package is installed"
  assert:
    that:
      - not pkg_status.changed

Java java-1.8.0 pkg_status. , java-1.8.0 , not pkg_status.changed true, . .

test_java.yml alpha-services/molecule/default/roles/test_alpha-services/tasks/main.yml :

---
- name: "include tasks for testing Java"
  include_tasks: "test_java.yml"

THEN : $ molecule verify. , :

$ molecule verify

--> Test matrix

└── default
    └── verify

--> Scenario: 'default'
--> Action: 'verify'
--> Running Ansible Verifier
--> Sanity checks: 'docker'

    PLAY [Verify] ******************************************************************

    TASK [Gathering Facts] *********************************************************
    ok: [instance]

    TASK [Include test_alpha-services] *********************************************

    TASK [test_alpha-services : include tasks for testing Java] ********************
    included: /Users/chukwudiuzoma/Documents/DevOps/ANSIBLE/MyTutorials/AnsibleTestingWithMolecule/alpha-services/molecule/default/roles/test_alpha-services/tasks/test_java.yml for instance

    TASK [test_alpha-services : Check Java package status] *************************
    changed: [instance]

    TASK [test_alpha-services : Test java package is installed] ********************
fatal: [instance]: FAILED! => {
    "assertion": "not pkg_status.changed",
    "changed": false,
    "evaluated_to": false,
    "msg": "Assertion failed"
}

    PLAY RECAP *********************************************************************
    instance                   : ok=3    changed=1    unreachable=0    failed=1    skipped=0    rescued=0    ignored=0

ERROR:

1. alpha-services/tasks/java.yml :

---
- name: "Install '{{ java_required_software }}'"
  package:
    name: "{{ java_required_software }}"
    lock_timeout: 60
    state: "present"

java.yml alpha-services/tasks/main.yml :

---
- name: "Include java installation tasks"
  include_tasks: "java.yml"

WHEN : $ molecule converge, .

THEN : $ molecule verify, , .

$ molecule verify

--> Test matrix

└── default
    └── verify

--> Scenario: 'default'
--> Action: 'verify'
--> Running Ansible Verifier
--> Sanity checks: 'docker'

    PLAY [Verify] ******************************************************************

    TASK [Gathering Facts] *********************************************************
    ok: [instance]

    TASK [Include test_alpha-services] *********************************************

    TASK [test_alpha-services : include tasks for testing Java] ********************
    included: /Users/chukwudiuzoma/Documents/DevOps/ANSIBLE/MyTutorials/AnsibleTestingWithMolecule/alpha-services/molecule/default/roles/test_alpha-services/tasks/test_java.yml for instance

    TASK [test_alpha-services : Check Java package status] *************************
    ok: [instance]

    TASK [test_alpha-services : Test java package is installed] ********************
    ok: [instance] => {
        "changed": false,
        "msg": "All assertions passed"
    }

    PLAY RECAP *********************************************************************
    instance                   : ok=4    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

Verifier completed successfully.

2. /var/log/tomcat, tomcat, tomcat 0755.

---
- name: "tomcat - '{{ test_tomcat_home_dir }}' - retrieve information from path"
  stat:
    path: "{{ test_tomcat_home_dir }}"
  register: directory

- name: "tomcat - assert that directory '{{ test_tomcat_home_dir }}' is created correctly"
  assert:
    that:
      - "directory.stat.exists"
      - "directory.stat.isdir"
      - "directory.stat.mode == {{ test_tomcat_mode }}"
      - "directory.stat.pw_name == {{ test_tomcat_user }}"
      - "directory.stat.gr_name == {{ test_tomcat_group}}"

yml- Molecule:

---
#TOMCAT
test_tomcat_mode: "0755"
test_tomcat_user: "tomcat"
test_tomcat_group: "tomcat"
test_tomcat_home_dir: "/var/log/tomcat"

stat Ansible , .

test_java.yml alpha-services/molecule/default/roles/test_alpha-services/tasks/main.yml :

---
- name: "include tasks for testing Tomcat"
  include_tasks: "test_tomcat.yml"

$ molecule verify, , . :

---
- name: "tomcat - create required tomcat logging directory"
  file:
    path: "{{ tomcat_home_dir }}"
    state: "directory"
    mode: "0755"
    owner: "{{ tomcat_user }}"
    group: "{{ tomcat_group }}"
    recurse: yes

yml :

---
#TOMCAT
tomcat_mode: "0755"
tomcat_user: "tomcat"
tomcat_group: "tomcat"
tomcat_home_dir: "/var/log/tomcat"

tomcat.yml alpha-services/tasks/main.yml :

---
- name: "Include java installation tasks"
  include_tasks: "java.yml"

: $ molecule converge, .

: $ molecule verify, , .

3: , httpd

, Ansible . Ansible, « Ansible — . , , , - . Ansible — , ».

, , , , :

TASK [alpha-services : httpd - start and enable httpd service] *****************
fatal: [instance]: FAILED! => {"changed": false, "msg": "Could not find the requested service httpd: host"}

:

---
- name: "Httpd - install httpd service"
  package:
    name: "httpd"
    state: "latest"

- name: "Httpd - start and enable httpd service"
  service:
    name: "httpd"
    state: "started"
    enabled: "yes"

, httpd Linux systemd, . , platforms Molelele.yml:

---
platforms:
  - name: instance
    image: docker.io/pycontribs/centos:7
    pre_build_image: false # we don't need ansible installed on the instance
    command: /sbin/init
    tmpfs:
      - /run
      - /tmp
    volumes:
      - /sys/fs/cgroup:/sys/fs/cgroup:ro
    privileged: true

systemd https://molecule.readthedocs.io/en/latest/examples.html

$ molecule create $ molecule converge. , httpd . httpd, :

$ molecule login         # this logs you into the docker container shell

$ systemctl | grep httpd
httpd.service loaded active running The Apache HTTP Server

$ exit                  # this logs you out of the docker container to your local terminal

4. template/tomcat/context.xml /etc/tomcat/context.xml.

, , -. , , , - , . , , . , , Ansible .

:

- name: "tomcat - test tomcat file"
  block:
    - name: "tomcat - retrieve information from path '{{ test_tomcat_context_xml_file }}'"
      stat:
        path: "{{ test_tomcat_context_xml_file }}"
      register: remote_file
    - name: "tomcat - assert that '{{ test_tomcat_context_xml_file }}' file is created correctly"
      assert:
        that:
          - "remote_file.stat.exists"
          - "remote_file.stat.isreg" # is a regular file
          - "remote_file.stat.path == '{{ test_tomcat_context_xml_file }}'"
          - "remote_file.stat.mode == '0755'"

test_tomcat_conf_dir: "/etc/tomcat"
test_tomcat_context_xml_file: "{{ test_tomcat_conf_dir }}/context.xml"

$ molecule verify, , . :

- name: "tomcat - copy dynamic tomcat server config files"
  template:
    src: "{{ tomcat_context_xml_file }}"
    dest: "{{ tomcat_conf_dir }}"

tomcat_conf_dir: "/etc/tomcat"
tomcat_context_xml_file: "tomcat/context.xml"

$ molecule converge, $ molecule verify. , .

, , $ molecule test, Molecule test_sequence. .

In conclusion, in my opinion, this is the right approach to developing Molecule tests for Ansible roles. The infrastructure code should be tested prior to deployment in a production environment to avoid unpleasant surprises. This tutorial was a simple demonstration of how you can test Ansible with Molecule using Ansible Verifier. Thus, there is no need to learn another programming language like Python, Ruby or Go.