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Chapter 3. Writing APBs

3.1. Writing APBs: Getting Started
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3.1.1. Overview
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In this tutorial, you will walk through the creation of some sample Ansible Playbook Bundles (APBs). You will create actions for them to allow provision, deprovision, bind, and unbind. You can find more information about the design of APBs in the Design topic. More in-depth information about writing APBs is available in the Reference topic.

Note

For the remainder of this tutorial, substitute your own information for items marked in brackets; for example, <host>:<port> might need to be replaced with 172.17.0.1.nip.io:8443.

3.1.2. Before You Begin
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Before getting started creating your own APBs, you must set up your development environment:

  1. Ensure you have access to an OpenShift Container Platform cluster. The cluster should be running both the service catalog and the OpenShift Ansible broker (OAB), which is supported starting with OpenShift Container Platform 3.7.
  2. Install the APB tools as documented in the CLI Tooling topic. To verify, you can run the apb help command and check for a valid response.

3.1.3. Creating Your First APB
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In this tutorial, you will create an APB for a containerized hello world application. You will work through a basic APB that will mirror the APB hello-world-apb.

  1. Your first task is to initialize the APB using the apb CLI tool. This creates the skeleton for your APB. The command for this is simple: 

    $ apb init my-test-apb
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    After initialization, you will see the following file structure: 

    my-test-apb/
├── apb.yml
├── Dockerfile
├── playbooks
│   ├── deprovision.yml
│   └── provision.yml
└── roles
    ├── deprovision-my-test-apb
    │   └── tasks
    │       └── main.yml
    └── provision-my-test-apb
        └── tasks
            └── main.yml
    Copy to Clipboard Toggle word wrap

    Two files were created at the root directory: an apb.yml (the APB spec file) and a Dockerfile. These are the minimum files required for any APB. For more information about the APB spec file, see the Reference topic. There is also an explanation of what you can do in the Dockerfile.

    apb.yml

    version: 1.0
name: my-test-apb
description: This is a sample application generated by apb init
bindable: False
async: optional
metadata:
  displayName: my-test
plans:
  - name: default
    description: This default plan deploys my-test-apb
    free: True
    metadata: {}
    parameters: []
    Copy to Clipboard Toggle word wrap

    Dockerfile

    FROM ansibleplaybookbundle/apb-base

LABEL "com.redhat.apb.spec"=\

COPY playbooks /opt/apb/actions
COPY roles /opt/ansible/roles
RUN chmod -R g=u /opt/{ansible,apb}
USER apb
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  2. In the Dockerfile, there are two updates to make:

    1. Change the FROM directive to use the image from the Red Hat Container Catalog. The first line should now read: 

      FROM openshift3/apb-base
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    2. Update com.redhat.apb.spec in the LABEL instruction with a base64 encoded version of apb.yml. To do this, run apb prepare: 

      $ cd my-test-apb
$ apb prepare
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      This updates the Dockerfile as follows:

      Dockerfile

      FROM openshift3/apb-base

LABEL "com.redhat.apb.spec"=\
"dmVyc2lvbjogMS4wCm5hbWU6IG15LXRlc3QtYXBiCmRlc2NyaXB0aW9uOiBUaGlzIGlzIGEgc2Ft\
cGxlIGFwcGxpY2F0aW9uIGdlbmVyYXRlZCBieSBhcGIgaW5pdApiaW5kYWJsZTogRmFsc2UKYXN5\
bmM6IG9wdGlvbmFsCm1ldGFkYXRhOgogIGRpc3BsYXlOYW1lOiBteS10ZXN0CnBsYW5zOgogIC0g\
bmFtZTogZGVmYXVsdAogICAgZGVzY3JpcHRpb246IFRoaXMgZGVmYXVsdCBwbGFuIGRlcGxveXMg\
bXktdGVzdC1hcGIKICAgIGZyZWU6IFRydWUKICAgIG1ldGFkYXRhOiB7fQogICAgcGFyYW1ldGVy\
czogW10="

COPY playbooks /opt/apb/actions
COPY roles /opt/ansible/roles
RUN chmod -R g=u /opt/{ansible,apb}
USER apb
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  3. At this point, you have a fully formed APB that you can build. If you skipped using apb prepare, the apb build command will still prepare the APB before building the image: 

    $ apb build
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  4. You can now push the new APB image to the local OpenShift Container Registry: 

    $ apb push
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  5. Querying the OAB will now show your new APB listed: 

    $ apb list
ID                                NAME            DESCRIPTION
< ------------ ID ------------->  dh-my-test-apb  This is a sample application generated by apb init
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    Similarly, visiting the OpenShift Container Platform web console will now display the new APB named my-test-apb in the service catalog under the All and Other tabs.

3.1.4. Adding Actions
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The brand new APB created in the last section does not do much in its current state. For that, you must add some actions. The actions supported are:

  • provision
  • deprovision
  • bind
  • unbind
  • test

You will add each of these actions in the following sections. But before beginning:

  1. Ensure that you are logged in to your OpenShift Container Platform cluster via the oc CLI. This will ensure the apb tool can interact with OpenShift Container Platform and the OAB: 

    # oc login <cluster_host>:<port> -u <user_name> -p <password>
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  2. Log in to the OpenShift Container Platform web console and verify your APB listed in the catalog:

    Figure 3.1. OpenShift Container Platform Web Console

    browse catalog my test
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    browse catalog my test

  3. Create a project named getting-started where you will deploy OpenShift Container Platform resources. You can create it using the web console or CLI: 

    $ oc new-project getting-started
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3.1.4.1. Provision
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During the apb init process, two parts of the provision task were stubbed out. The playbook, playbooks/provision.yml, and the associated role in roles/provision-my-test-apb: 

my-test-apb
├── apb.yml
├── Dockerfile
├── playbooks
│   └── provision.yml
1 

└── roles
    └── provision-my-test-apb
        └── tasks
            └── main.yml
2
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1
Inspect this playbook.
2
Edit this role.

The playbooks/provision.yml file is the Ansible playbook that will be run when the provision action is called from the OAB. You can change the playbook, but for now you can just leave the code as is.

playbooks/provision.yml

- name: my-test-apb playbook to provision the application
  hosts: localhost
  gather_facts: false
  connection: local
  roles:
  - role: ansible.kubernetes-modules
    install_python_requirements: no
  - role: ansibleplaybookbundle.asb-modules
  - role: provision-my-test-apb
    playbook_debug: false
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The playbook will execute on localhost and execute the role provision-my-test-apb. This playbook works on its local container created by the service broker. The ansible.kubernetes-modules role allow you to use the kubernetes-modules to create your OpenShift Container Platform resources. The asb-modules provide additional functionality for use with the OAB.

Currently, there are no tasks in the role. The contents of the roles/provision-my-test-apb/tasks/main.yml only contains comments showing common resource creation tasks. ou can currently execute the provision task, but since there are no tasks to perform, it would simply launch the APB container and exit without deploying anything.

You can try this now by clicking on the my-test APB and deploying it to the getting-started project using the web console:

Figure 3.2. Provisioning my-test

provision my test
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provision my test

When the provision is executing, a new namespace is created with the name dh-my-test-apb-prov-<random>. In development mode, it will persist, but usually this namespace would be deleted after successful completion. If the APB fails provisioning, the namespace will persist by default.

By looking at the pod resources, you can see the log for the execution of the APB. To view the pod’s logs:

  1. Find the namespaces by either using the web console to view all namespaces and sort by creation date, or using the following command: 

    $ oc get ns
NAME                                STATUS    AGE
ansible-service-broker              Active    1h
default                             Active    1h
dh-my-test-apb-prov-<random>        Active    4m
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  2. Switch to the project: 

    $ oc project dh-my-test-apb-prov-<random>
Now using project "dh-my-test-apb-prov-<random>" on server "<cluster_host>:<port>".
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  3. Get the pod name: 

    $ oc get pods
NAME             READY     STATUS      RESTARTS   AGE
<apb_pod_name>   0/1       Completed   0          3m
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  4. View the logs: 

    $ oc logs -f <apb_pod_name>
...
+ ansible-playbook /opt/apb/actions/provision.yml --extra-vars '{"_apb_plan_id":"default","namespace":"getting-started"}'
PLAY [my-test-apb playbook to provision the application] ***********************
TASK [ansible.kubernetes-modules : Install latest openshift client] *************
skipping: [localhost]
TASK [ansibleplaybookbundle.asb-modules : debug] *******************************
skipping: [localhost]
PLAY RECAP *********************************************************************
localhost                  : ok=0    changed=0    unreachable=0    failed=0
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3.1.4.1.1. Creating a Deploying Configuration
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At the minimum, your APB should deploy the application pods. You can do this by specifying a deployment configuration:

  1. One of the first tasks that is commented out in the provision-my-test-apb/tasks/main.yml file is the creation of the deployment configuration. You can uncomment it or paste the following:

    Note

    Normally, you would replace the image: value with your own application image. 

    - name: create deployment config
  openshift_v1_deployment_config:
    name: my-test
    namespace: '{{ namespace }}'
    1 
    
    labels:
    2 
    
      app: my-test
      service: my-test
    replicas: 1
    3 
    
    selector:
    4 
    
      app: my-test
      service: my-test
    spec_template_metadata_labels:
      app: my-test
      service: my-test
    containers:
    5 
    
    - env:
      image: docker.io/ansibleplaybookbundle/hello-world:latest
      name: my-test
      ports:
      - container_port: 8080
        protocol: TCP
    Copy to Clipboard Toggle word wrap
    1
    Designates which namespace the deployment configuration should be in.
    2
    Used to help organize, group, and select objects.
    3
    Specifies that you only want one pod.
    4
    The selector section is a labels query over pods.
    5
    This containers section specifies a container with a hello-world application running on port 8080 on TCP. The image is stored at docker.io/ansibleplaybookbundle/hello-world.

    For more information, Writing APBs: Reference has more detail, and you can see the ansible-kubernetes-modules documentation for a full accounting of all fields.

  2. Build and push the APB: 

    $ apb build
$ apb push
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  3. Provision the APB using the web console.

  4. After provisioning, there will be a new running pod and a new deployment configuration. Verify by checking your OpenShift Container Platform resources: 

    $ oc project getting-started
$ oc get all
NAME         REVISION   DESIRED   CURRENT   TRIGGERED BY
dc/my-test   1          1         1         config

NAME           DESIRED   CURRENT   READY     AGE
rc/my-test-1   1         1         1         35s

NAME                 READY     STATUS    RESTARTS   AGE
po/my-test-1-2pw4t   1/1       Running   0          33s
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    You will also be able to see the deployed application in the web console on the project’s Overview page.

The only way to use this pod in its current state is to use: 

$ oc describe pods/<pod_name>
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to find its IP address and access it directly. If there were multiple pods, they would be accessed separately. To treat them like a single host, you need to create a service, described in the next section.

Tip

To clean up before moving on and allow you to provision again, you can delete the getting-started project and recreate it or create a new one.

3.1.4.1.2. Creating a Service
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You will want to use multiple pods, load balance them, and create a service so that a user can access them as a single host:

  1. Modify the provision-my-test-apb/tasks/main.yml file and add the following: 

    - name: create my-test service
  k8s_v1_service:
    name: my-test
    namespace: '{{ namespace }}'
    labels:
      app: my-test
      service: my-test
    selector:
      app: my-test
      service: my-test
    ports:
      - name: web
        port: 80
        target_port: 8080
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    The selector section will allow the my-test service to include the correct pods. The ports will take the target port from the pods (8080) and expose them as a single port for the service (80). Notice the application was running on 8080 but has now been made available on the default HTTP port of 80.

    The name field of the port allows you to specify this port in the future with other resources. More information is available in the k8s_v1_service module.

  2. Build and push the APB: 

    $ apb build
$ apb push
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  3. Provision the APB using the web console.

After provisioning, you will see a new service in the web console or CLI. In the web console, you can click on the new service under Networking in the application on the Overview page or under Applications Services. The service’s IP address will be shown which you can use to access the load balanced application.

To view the service information from the command line, you can do the following: 

$ oc project getting-started
$ oc get services
$ oc describe services/my-test
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The describe command will show the IP address to access the service. However, using an IP address for users to access your application is not generally what you want. Instead, you should create a route, described in the next section.

Tip

To clean up before moving on and allow you to provision again, you can delete the getting-started project and recreate it or create a new one.

3.1.4.1.3. Creating a Route
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You can expose external access to your application through a reliable named route:

  1. Modify the provision-my-test-apb/tasks/main.yml file and adding the following: 

    - name: create my-test route
  openshift_v1_route:
    name: my-test
    namespace: '{{ namespace }}'
    labels:
      app: my-test
      service: my-test
    to_name: my-test
    spec_port_target_port: web
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    The to_name is the name of the target service. The spec_port_target_port refers to the name of the target service’s port. More information is available in the openshift_v1_route module.

  2. Build and push the APB: 

    $ apb build
$ apb push
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  3. Provision the APB using the web console.

After provisioning, you will see the new route created. On the web console’s Overview page for the getting-started project, you will now see an active and clickable route link listed on the application. Clicking on the route or visiting the URL will bring up the hello-world application.

You can also view the route information from the CLI: 

$ oc project getting-started

$ oc get routes
NAME      HOST/PORT                                   PATH      SERVICES   PORT      TERMINATION   WILDCARD
my-test   my-test-getting-started.172.17.0.1.nip.io             my-test    web                     None

$ oc describe routes/my-test
Name:			my-test
Namespace:		getting-started
...
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At this point, your my-test application is fully functional, load balanced, scalable, and accessible. You can compare your finished APB to the hello-world APB in the hello-world-apb example repository.

3.1.4.2. Deprovision
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For the deprovision task, you must destroy all provisioned resources, usually in reverse order from how they were created.

To add the deprovision action, you need a deprovision.yml file under playbooks/ directory and related tasks in the roles/deprovision-my-test-apb/tasks/main.yml. Both these files should already be created for you: 

my-test-apb/
├── apb.yml
├── Dockerfile
├── playbooks
│   └── deprovision.yml
1 

└── roles
    └── deprovision-my-test-apb
        └── tasks
            └── main.yml
2
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1
Inspect this file.
2
Edit this file.

The content of the deprovision.yml file looks the same as the provision task, except it is calling a different role:

playbooks/deprovision.yml

- name: my-test-apb playbook to deprovision the application
  hosts: localhost
  gather_facts: false
  connection: local
  roles:
  - role: ansible.kubernetes-modules
    install_python_requirements: no
  - role: ansibleplaybookbundle.asb-modules
  - role: deprovision-my-test-apb
    playbook_debug: false
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Edit that role in the file roles/deprovision-my-test-apb/tasks/main.yml. By uncommenting the tasks, the resulting file without comments should look like the following: 

- openshift_v1_route:
    name: my-test
    namespace: '{{ namespace }}'
    state: absent

- k8s_v1_service:
    name: my-test
    namespace: '{{ namespace }}'
    state: absent

- openshift_v1_deployment_config:
    name: my-test
    namespace: '{{ namespace }}'
    state: absent
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In the provision.yml file created earlier, you created a deployment configuration, service, then route. For the deprovision action, you should delete the resources in reverse order. You can do so by identifying the resource by namespace and name, and then marking it as state: absent.

To run the deprovision template, click on the menu on the list of Deployed Services and select Delete.

3.1.4.2.1. Bind
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From the previous sections, you learned how to deploy a standalone application. However, in most cases applications will need to communicate with other applications, and often with a data source. In the following sections, you will create a PostgreSQL database that the hello-world application deployed from my-test-apb can use.

3.1.4.2.1.1. Preparation
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For a good starting point, create the necessary files for provision and deprovisioning PostgreSQL.

Note

A more in-depth example can be found at the PostgreSQL example APB.

  1. Initialize the APB using the --bindable option: 

    $ apb init my-pg-apb --bindable
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    This creates the normal APB file structure with a few differences: 

    my-pg-apb/
├── apb.yml
    1 
    
├── Dockerfile
├── playbooks
│   ├── bind.yml
    2 
    
│   ├── deprovision.yml
│   ├── provision.yml
│   └── unbind.yml
    3 
    
└── roles
    ├── bind-my-pg-apb
    │   └── tasks
    │       └── main.yml
    4 
    
    ├── deprovision-my-pg-apb
    │   └── tasks
    │       └── main.yml
    ├── provision-my-pg-apb
    │   └── tasks
    │       └── main.yml
    5 
    
    └── unbind-my-pg-apb
        └── tasks
            └── main.yml
    6
    Copy to Clipboard Toggle word wrap
    1
    bindable flag set to true
    2
    New file
    3
    New file
    4
    New empty file
    5
    Encoded binding credentials
    6
    New empty file

    In addition to the normal files, new playbooks bind.yml, unbind.yml, and their associated roles have been stubbed out. The bind.yml and unbind.yml files are both empty and, because you are using the default binding behavior, will remain empty.

  2. Edit the apb.yml file. Notice the setting bindable: true. In addition to those changes, you must add some parameters to the apb.yml for configuring PostgreSQL. They will be available fields in the web console when provisioning your new APB: 

    version: 1.0
name: my-pg-apb
description: This is a sample application generated by apb init
bindable: True
async: optional
metadata:
  displayName: my-pg
plans:
  - name: default
    description: This default plan deploys my-pg-apb
    free: True
    metadata: {}
    # edit the parameters and add the ones below.
    parameters:
      - name: postgresql_database
        title: PostgreSQL Database Name
        type: string
        default: admin
      - name: postgresql_user
        title: PostgreSQL User
        type: string
        default: admin
      - name: postgresql_password
        title: PostgreSQL Password
        type: string
        default: admin
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    The playbooks/provision.yml will look like the following: 

    - name: my-pg-apb playbook to provision the application
  hosts: localhost
  gather_facts: false
  connection: local
  roles:
  - role: ansible.kubernetes-modules
    install_python_requirements: no
  - role: ansibleplaybookbundle.asb-modules
  - role: provision-my-pg-apb
    playbook_debug: false
    Copy to Clipboard Toggle word wrap

    The playbooks/deprovision.yml will look like the following: 

    - name: my-pg-apb playbook to deprovision the application
  hosts: localhost
  gather_facts: false
  connection: local
  roles:
  - role: ansible.kubernetes-modules
    install_python_requirements: no
  - role: deprovision-my-pg-apb
    playbook_debug: false
    Copy to Clipboard Toggle word wrap

  3. Edit the roles/provision-my-pg-apb/tasks/main.yml file. This file mirrors your hello-world application in many respects, but adds a persistent volume (PV) to save data between restarts and various configuration options for the deployment configuration.

    In addition, a new task has been added at the very bottom after the provision tasks. To save the credentials created during the provision process, you must encode them for retrieval by the OAB. The new task, using the module asb_encode_binding, will do so for you.

    You can safely delete everything in that file and replace it with the following: 

    # New persistent volume claim
- name: create volumes
  k8s_v1_persistent_volume_claim:
    name: my-pg
    namespace: '{{ namespace }}'
    state: present
    access_modes:
      - ReadWriteOnce
    resources_requests:
      storage: 1Gi

- name: create deployment config
  openshift_v1_deployment_config:
    name: my-pg
    namespace: '{{ namespace }}'
    labels:
      app: my-pg
      service: my-pg
    replicas: 1
    selector:
      app: my-pg
      service: my-pg
    spec_template_metadata_labels:
      app: my-pg
      service: my-pg
    containers:
    - env:
      - name: POSTGRESQL_PASSWORD
        value: '{{ postgresql_password }}'
      - name: POSTGRESQL_USER
        value: '{{ postgresql_user }}'
      - name: POSTGRESQL_DATABASE
        value: '{{ postgresql_database }}'
      image: docker.io/centos/postgresql-94-centos7
      name: my-pg
      ports:
      - container_port: 5432
        protocol: TCP
      termination_message_path: /dev/termination-log
      volume_mounts:
      - mount_path: /var/lib/pgsql/data
        name: my-pg
      working_dir: /
    volumes:
    - name: my-pg
      persistent_volume_claim:
        claim_name: my-pg
      test: false
      triggers:
      - type: ConfigChange

- name: create service
  k8s_v1_service:
    name: my-pg
    namespace: '{{ namespace }}'
    state: present
    labels:
      app: my-pg
      service: my-pg
    selector:
      app: my-pg
      service: my-pg
    ports:
    - name: port-5432
      port: 5432
      protocol: TCP
      target_port: 5432

# New encoding task makes credentials available to future bind operations
- name: encode bind credentials
  asb_encode_binding:
    fields:
      DB_TYPE: postgres
      DB_HOST: my-pg
      DB_PORT: "5432"
      DB_USER: "{{ postgresql_user }}"
      DB_PASSWORD: "{{ postgresql_password }}"
      DB_NAME: "{{ postgresql_database }}"
    Copy to Clipboard Toggle word wrap

    The encode bind credentials task will make available several fields as environment variables: DB_TYPE, DB_HOST, DB_PORT, DB_USER, DB_PASSWORD, and DB_NAME. This is the default behavior when the bind.yml file is left empty. Any application (such as hello-world) can use these environment variables to connect to the configured database after performing a bind operation.

  4. Edit the roles/deprovision-my-pg-apb/tasks/main.yml and uncomment the following lines so that the created resources will be deleted during deprovisioning: 

    - k8s_v1_service:
    name: my-pg
    namespace: '{{ namespace }}'
    state: absent

- openshift_v1_deployment_config:
    name: my-pg
    namespace: '{{ namespace }}'
    state: absent

- k8s_v1_persistent_volume_claim:
    name: my-pg
    namespace: '{{ namespace }}'
    state: absent
    Copy to Clipboard Toggle word wrap

  5. Finally, build and push your APB: 

    $ apb build
$ apb push
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At this point, the APB can create a fully functional PostgreSQL database to your cluster. You can test it out in the next section.

3.1.4.2.1.2. Executing From the UI
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To test your application, you can bind a hello-world application to the provisioned PostgreSQL database. You can use the application previously created in the Provision section of this tutorial, or you can use the hello-world-apb:

  1. First, provision my-test-apb.

  2. Then, provision my-pg-apb and select the option to Create a secret:

    provision my pg
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    provision my pg
    provision my pg params
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    provision my pg params
    provision my pg binding
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    provision my pg binding
    provision my pg results
    View larger image
    provision my pg results
  3. Now, if you have not already done so, navigate to the project. You can see both your hello-world application and your PostgreSQL database. If you did not select to create a binding at provision time, you can also do so here with the Create binding link.

  4. After you the binding has been created, you must add the secret created by the binding into the application. First, navigate to the secrets on the Resources Secrets page:

    my pg nav secrets
    View larger image
    my pg nav secrets
    my pg secrets
    View larger image
    my pg secrets

  5. Add the secret as environment variables:

    my pg add secret
    View larger image
    my pg add secret
    my pg add secret app
    View larger image
    my pg add secret app

  6. After this addition, you can return to the Overview page. The my-test application may still be redeploying from the configuration change. If so, wait until you can click on the route to view the application:

    my pg overview
    View larger image
    my pg overview

    After clicking the route, you will see the hello-world application has detected and connected to the my-pg database:

    my pg hello world
    View larger image
    my pg hello world
3.1.4.2.2. Test
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Test actions are intended to check that an APB passes a basic sanity check before publishing to the service catalog. They are not meant to test a live service. OpenShift Container Platform provides the ability to test a live service using liveness and readiness probes, which you can add when provisioning.

The actual implementation of your test is left to you as the APB author. The following sections provide guidance and best practices.

3.1.4.2.2.1. Writing a Test Action
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To create a test action for your APB:

  • Include a playbooks/test.yml file.
  • Include defaults for the test in the playbooks/vars/ directory. 
my-apb/
├── ...
├── playbooks/
    ├── test.yml
    └── vars/
        └── test_defaults.yml
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To orchestrate the testing of an APB, you should use the include_vars and include_role modules in your test.yml file:

test.yml

- name: test media wiki abp
  hosts: localhost
  gather_facts: false
  connection: local

  roles:
  - role: ansible.kubernetes-modules
1 

    install_python_requirements: no

  post_tasks:
  - name: Load default variables for testing
2 

    include_vars: test_defaults.yaml
  - name: create project for namespace
    openshift_v1_project:
      name: '{{ namespace }}'
  - name: Run the provision role.
3 

    include_role:
      name: provision-mediawiki123-apb
  - name: Run the verify role.
4 

    include_role:
      name: verify-mediawiki123-apb
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1
Load the Ansible Kubernetes modules.
2
Include the default values needed for provision from the test role.
3
Include the provision role to run.
4
Include the verify role to run. See Writing a Verify Role.
3.1.4.2.2.2. Writing a Verify Role
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A verify role allows you to determine if the provision has failed or succeeded. The verify_<name> role should be in the roles/ directory. This should be a normal Ansible role. 

my-apb/
├── ...
└── roles/
    ├── ...
    └── verify_<name>
        ├── defaults
             └── defaults.yml
        └── tasks
            └── main.yml
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An example task in the main.yml file could look like: 

 - name: url check for media wiki
   uri:
     url: "http://{{ route.route.spec.host }}"
     return_content: yes
   register: webpage
   failed_when: webpage.status != 200
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3.1.4.2.2.3. Saving Test Results
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The asb_save_test_result module can also be used in the verify role, allowing the APB to save test results so that the apb test command can return them. The APB pod will stay alive for the tool to retrieve the test results.

For example, adding asb_save_test_result usage to the previous main.yml example: 

 - name: url check for media wiki
   uri:
     url: "http://{{ route.route.spec.host }}"
     return_content: yes
   register: webpage

  - name: Save failure for the web page
    asb_save_test_result:
      fail: true
      msg: "Could not reach route and retrieve a 200 status code. Recieved status - {{ webpage.status }}"
    when: webpage.status != 200

  - fail:
      msg: "Could not reach route and retrieve a 200 status code. Recieved status - {{ webpage.status }}"
    when: webpage.status != 200

  - name: Save test pass
    asb_save_test_result:
      fail: false
    when: webpage.status == 200
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3.1.4.2.2.4. Running a Test Action
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After you have defined your test action, you can use the CLI tooling to run the test: 

$ apb test
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The test action will:

  • build the image,
  • start up a pod as if it was being run by the service broker, and
  • retrieve the test results if any were saved.

The status of pod after execution has finished will determine the status of the test. If the pod is in an error state, then something failed and the command reports that the test was unsuccessful.

3.2. Writing APBs: Reference
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3.2.1. Overview
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While the Getting Started topic provides a step by step walkthrough on creating your first Ansible Playbook Bundle (APB), this topic provides more in-depth reference material. The fundamental components that make up an APB are explained in further detail to help an experienced APB developer get a better understanding of each individual component within an APB.

For completed APB examples, you can browse APBs in the ansibleplaybookbundle organization on GitHub.

3.2.2. Directory Structure
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The following shows an example directory structure of an APB: 

example-apb/
├── Dockerfile
├── apb.yml
└── roles/
│   └── example-apb-openshift
│       ├── defaults
│       │   └── main.yml
│       └── tasks
│           └── main.yml
└── playbooks/
    └── provision.yml
    └── deprovision.yml
    └── bind.yml
    └── unbind.yml
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3.2.3. APB Spec File
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The APB spec file is located at apb.yml and is where the outline of your application is declared. The following is an example APB spec: 

  version: 1.0
  name: example-apb
  description: A short description of what this APB does
  bindable: True
  async: optional
1 

  metadata:
    documentationUrl: <link_to_documentation>
    imageUrl: <link_to_url_of_image>
    dependencies: ['<registry>/<organization>/<dependency_name_1>', '<registry>/<organization>/<dependency_name_2>']
    displayName: Example App (APB)
    longDescription: A longer description of what this APB does
    providerDisplayName: "Red Hat, Inc."
  plans:
    - name: default
      description: A short description of what this plan does
      free: true
      metadata:
        displayName: Default
        longDescription: A longer description of what this plan deploys
        cost: $0.00
      parameters:
        - name: parameter_one
          required: true
          default: foo_string
          type: string
          title: Parameter One
          maxlength: 63
        - name: parameter_two
          required: true
          default: true
          title: Parameter Two
          type: boolean
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1
Async bind and unbind is an experimental feature and is not supported or enabled by default.

3.2.3.1. Top-level Structure
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Expand
FieldDescription

version

Version of the APB spec. See APB Spec Versioning for details.

name

Name of the APB. Names must be valid ASCII and may contain lowercase letters, digits, underscores, periods, and dashes. See Docker’s guidelines for valid tag names.

description

Short description of this APB.

bindable

Boolean option of whether or not this APB can be bound to. Accepted fields are true or false.

metadata

Dictionary field declaring relevant metadata information.

plans

A list of plans that can be deployed. See Plans for details.

3.2.3.2. Metadata
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Expand
FieldDescription

documentationUrl

URL to the application’s documentation.

imageUrl

URL to an image which will be displayed in the web console for the service catalog.

dependencies

List of images which are consumed from within the APB.

displayName

The name that will be displayed in the web console for this APB.

longDescription

Longer description that will be displayed when the APB is clicked in the web console.

providerDisplayName

Name of who is providing this APB for consumption.

3.2.3.3. Plans
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Plans are declared as a list. This section explains what each field in a plan describes.

Expand
FieldDescription

name

Unique name of plan to deploy. This will be displayed when the APB is clicked from the service catalog.

description

Short description of what will be deployed from this plan.

free

Boolean field to determine if this plan is free or not. Accepted fields are true or false.

metadata

Dictionary field declaring relevant plan metadata information. See Plan Metadata for details.

parameters

List of parameter dictionaries used as input to the APB. See Parameters for details.

3.2.3.4. Plan Metadata
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Expand
FieldDescription

displayName

Name to display for the plan in the web console.

longDescription

Longer description of what this plan deploys.

cost

How much the plan will cost to deploy. Accepted field is $x.yz.

3.2.3.5. Parameters
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Each item in the parameters section can have several fields. The name field is required. The order of the parameters will be displayed in sequential order in the form in the OpenShift Container Platform web console. 

parameters:
  - name: my_param
    title: My Parameter
    type: enum
    enum: ['X', 'Y', 'Z']
    required: True
    default: X
    display_type: select
    display_group: Group 1
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Expand
FieldDescription

name

Unique name of the parameter passed into the APB.

title

Displayed label in the web console.

type

Data type of the parameters as specified by link json-schema, such as string, number, int, boolean, or enum. Default input field type in the web console will be assigned if no display_type is assigned.

required

Whether or not the parameter is required for APB execution. Required field in the web console.

default

Default value assigned to the parameter.

display_type

Display type for the web console. For example, you can override a string input as a password to hide it in the web console. Accepted fields include text, textarea, password, checkbox, or select.

display_group

Will cause a parameter to display in groups with adjacent parameters with matching display_group fields. In the above example, adding another field below with display_group: Group 1 will visually group them together in the web console under the heading Group 1.

When using a long list of parameters, it can be useful to use a shared parameter list. For an example of this, see the rhscl-postgresql-apb.

3.2.3.6. APB Spec Versioning
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The APB spec uses semantic versioning with the format of x.y where x is a major release and y is a minor release.

The current spec version is 1.0.

3.2.3.6.1. Major Version
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The APB spec will increment the major version whenever an API breaking change is introduced to the spec. Some examples include:

  • Introduction or deletion of a required field.
  • Changing the YAML format.
  • New features.
3.2.3.6.2. Minor Version
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The APB spec will increment the minor version whenever a non-breaking change is introduced to the spec. Some examples include:

  • Introduction or deletion of an optional field.
  • Spelling change.
  • Introduction of new options to an existing field.

3.2.4. Dockerfile
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The Dockerfile is what is used to actually build the APB image. As a result, sometimes you will need to customize it for your own needs. For example, if running a playbook that requires interactions with PostgreSQL, you may want to install the required packages by adding the yum install command: 

FROM ansibleplaybookbundle/apb-base
MAINTAINER Ansible Playbook Bundle Community

LABEL "com.redhat.apb.spec"=\
"<------------base64-encoded-spec------------>"


COPY roles /opt/ansible/roles
COPY playbooks /opt/apb/actions
RUN chmod -R g=u /opt/{ansible,apb}


### INSTALL THE REQUIRED PACKAGES
RUN yum -y install python-boto postgresql && yum clean all

USER apb
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3.2.5. APB Actions (Playbooks)
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An action for an APB is the command that the APB is run with. The standard actions that are supported are:

  • provision
  • deprovision
  • bind
  • unbind
  • test

For an action to be valid, there must be a valid file in the playbooks/ directory named <action>.yml. These playbooks can do anything, which also means that you can technically create any action you would like. For example, the mediawiki-apb has playbook creating an update action.

Most APBs will normally have a provision action to create resources and a deprovision action to destroy the resources when deleting the service.

The bind and unbind actions are used when the coordinates of one service needs to be made available to another service. This is often the case when creating a data service and making it available to an application. Currently, the coordinates are made available during the provision.

To properly make your coordinates available to another service, use the asb_encode_binding module. This module should be called at the end of the APB’s provision role, and it will return bind credentials to the OpenShift Ansible broker (OAB): 

- name: encode bind credentials
  asb_encode_binding:
    fields:
      EXAMPLE_FIELD: foo
      EXAMPLE_FIELD2: foo2
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3.2.6. Working With Common Resources
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This section describes a list of common OpenShift Container Platform resources that are created when developing APBs. See the Ansible Kubernetes Module for a full list of available resource modules.

3.2.6.1. Service
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The following is a sample Ansible task to create a service named hello-world. The namespace variable in an APB will be provided by the OAB when launched from the web console.

Provision

- name: create hello-world service
  k8s_v1_service:
    name: hello-world
    namespace: '{{ namespace }}'
    labels:
      app: hello-world
      service: hello-world
    selector:
      app: hello-world
      service: hello-world
    ports:
      - name: web
        port: 8080
        target_port: 8080
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Deprovision

- k8s_v1_service:
    name: hello-world
    namespace: '{{ namespace }}'
    state: absent
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3.2.6.2. Deployment Configuration
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The following is a sample Ansible task to create a deployment configuration for the image docker.io/ansibleplaybookbundle/hello-world which maps to service hello-world.

Provision

- name: create deployment config
  openshift_v1_deployment_config:
    name: hello-world
    namespace: '{{ namespace }}'
    labels:
      app: hello-world
      service: hello-world
    replicas: 1
    selector:
      app: hello-world
      service: hello-world
    spec_template_metadata_labels:
      app: hello-world
      service: hello-world
    containers:
    - env:
      image: docker.io/ansibleplaybookbundle/hello-world:latest
      name: hello-world
      ports:
      - container_port: 8080
        protocol: TCP
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Deprovision

- openshift_v1_deployment_config:
    name: hello-world
    namespace: '{{ namespace }}'
    state: absent
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3.2.6.3. Route
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The following is an example of creating a route named hello-world which maps to the service hello-world.

Provision

- name: create hello-world route
  openshift_v1_route:
    name: hello-world
    namespace: '{{ namespace }}'
    spec_port_target_port: web
    labels:
      app: hello-world
      service: hello-world
    to_name: hello-world
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Deprovision

- openshift_v1_route:
    name: hello-world
    namespace: '{{ namespace }}'
    state: absent
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3.2.6.4. Persistent Volume
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The following is an example of creating a persistent volume claim (PVC) resource and deployment configuration that uses it.

Provision

# Persistent volume resource
- name: create volume claim
  k8s_v1_persistent_volume_claim:
    name: hello-world-db
    namespace: '{{ namespace }}'
    state: present
    access_modes:
      - ReadWriteOnce
    resources_requests:
      storage: 1Gi
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In addition to the resource, add your volume to the deployment configuration declaration: 

- name: create hello-world-db deployment config
  openshift_v1_deployment_config:
    name: hello-world-db
    ---
    volumes:
    - name: hello-world-db
      persistent_volume_claim:
        claim_name: hello-world-db
      test: false
      triggers:
      - type: ConfigChange
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Deprovision

- openshift_v1_deployment_config:
    name: hello-world-db
    namespace: '{{ namespace }}'
    state: absent

- k8s_v1_persistent_volume_claim:
    name: hello-world-db
    namespace: '{{ namespace }}'
    state: absent
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3.2.7. Optional Variables
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You can add optional variables to an APB by using environment variables. To pass variables into an APB, you must escape the variable substitution in your .yml files.

For example, consider the following roles/provision-etherpad-apb/tasks/main.yml file in the etherpad-apb: 

- name: create mariadb deployment config
  openshift_v1_deployment_config:
    name: mariadb
    namespace: '{{ namespace }}'
    ...
    - env:
      - name: MYSQL_ROOT_PASSWORD
        value: '{{ mariadb_root_password }}'
      - name: MYSQL_DATABASE
        value: '{{ mariadb_name }}'
      - name: MYSQL_USER
        value: '{{ mariadb_user }}'
      - name: MYSQL_PASSWORD
        value: '{{ mariadb_password }}'
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Variables for the APB are defined in the roles/provision-etherpad-apb/defaults/main.yml file: 

playbook_debug: no
mariadb_root_password: "{{ lookup('env','MYSQL_ROOT_PASSWORD') | default('admin', true) }}"
mariadb_name: "{{ lookup('env','MYSQL_DATABASE') | default('etherpad', true) }}"
mariadb_user: "{{ lookup('env','MYSQL_USER') | default('etherpad', true) }}"
mariadb_password: "{{ lookup('env','MYSQL_PASSWORD') | default('admin', true) }}"
etherpad_admin_password: "{{ lookup('env','ETHERPAD_ADMIN_PASSWORD') | default('admin', true) }}"
etherpad_admin_user: "{{ lookup('env','ETHERPAD_ADMIN_USER') | default('etherpad', true) }}"
etherpad_db_host: "{{ lookup('env','ETHERPAD_DB_HOST') | default('mariadb', true) }}"
state: present
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3.2.8. Working With the Restricted SCC
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When building an OpenShift Container Platform image, it is important that you do not have your application running as the root user when at all possible. When running under the restriced security context, the application image is launched with a random UID. This causes problems if your application folder is owned by the root user.

A good way to work around this is to add a user to the root group and make the application folder owned by the root group. See OpenShift Container Platform-Specific Guidelines for details on supporting arbitrary user IDs.

The following is a Dockerfile example of a node application running in /usr/src. This command would be run after the application is installed in /usr/src and the associated environment variables set: 

ENV USER_NAME=haste \
    USER_UID=1001 \
    HOME=/usr/src

RUN useradd -u ${USER_UID} -r -g 0 -M -d /usr/src -b /usr/src -s /sbin/nologin -c "<username> user" ${USER_NAME} \
               && chown -R ${USER_NAME}:0 /usr/src \
               && chmod -R g=u /usr/src /etc/passwd
USER 1001
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3.2.9. Using a ConfigMap Within an APB
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There is a temporary workaround for creating ConfigMaps from Ansible due to a bug in the Ansible modules.

One common use case for ConfigMaps is when the parameters of an APB will be used within a configuration file of an application or service. The ConfigMap module allows you to mount a ConfigMap into a pod as a volume, which can be used to store the configuration file. This approach allows you to also leverage the power of Ansible’s template module to create a ConfigMap out of APB paramters.

The following is an example of creating a ConfigMap from a Jinja template mounted into a pod as a volume: 

- name: Create hastebin config from template
  template:
    src: config.js.j2
    dest: /tmp/config.js

- name: Create hastebin configmap
  shell: oc create configmap haste-config --from-file=haste-config=/tmp/config.js

<snip>

- name: create deployment config
  openshift_v1_deployment_config:
    name: hastebin
    namespace: '{{ namespace }}'
    labels:
      app: hastebin
      service: hastebin
    replicas: 1
    selector:
      app: hastebin
      service: hastebin
    spec_template_metadata_labels:
      app: hastebin
      service: hastebin
    containers:
    - env:
      image: docker.io/dymurray/hastebin:latest
      name: hastebin
      ports:
      - container_port: 7777
        protocol: TCP
      volumeMounts:
        - mountPath: /usr/src/haste-server/config
          name: config
    - env:
      image: docker.io/modularitycontainers/memcached:latest
      name: memcached
      ports:
      - container_port: 11211
        protocol: TCP
    volumes:
      - name: config
        configMap:
          name: haste-config
          items:
            - key: haste-config
              path: config.js
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