Exercise 2.3 - Projects & job templates

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A Tower Project is a logical collection of Ansible Playbooks. You can manage your playbooks by placing them into a source code management (SCM) system supported by Tower, including Git, Subversion, and Mercurial.

You should definitely keep your Playbooks under version control. In this lab we’ll use Playbooks kept in a Git repository.

Setup Git Repository

For this demonstration we will use playbooks stored in a Git repository:

https://github.com/ansible/workshop-examples

A Playbook to install the Apache webserver has already been commited to the directory rhel/apache, apache_install.yml:

---
- name: Apache server installed
  hosts: all

  tasks:
  - name: latest Apache version installed
    yum:
      name: httpd
      state: latest

  - name: latest firewalld version installed
    yum:
      name: firewalld
      state: latest

  - name: firewalld enabled and running
    service:
      name: firewalld
      enabled: true
      state: started

  - name: firewalld permits http service
    firewalld:
      service: http
      permanent: true
      state: enabled
      immediate: yes

  - name: Apache enabled and running
    service:
      name: httpd
      enabled: true
      state: started

Tip

Note the difference to other Playbooks you might have written! Most importantly there is no become and hosts is set to all.

To configure and use this repository as a Source Control Management (SCM) system in Tower you have to create a Project that uses the repository

Create the Project

• Go to RESOURCES → Projects in the side menu view click the button. Fill in the form:

• NAME: Ansible Workshop Examples

• ORGANIZATION: Default

• SCM TYPE: Git

Now you need the URL to access the repo. Go to the Github repository mentioned above, choose the green Clone or download button on the right, click on Use https and copy the HTTPS URL.

Note

If there is no Use https to click on, but a Use SSH, you are fine: just copy the URL. The important thing is that you copy the URL starting with https.

Enter the URL into the Project configuration:

• SCM URL: https://github.com/ansible/workshop-examples.git

• SCM UPDATE OPTIONS: Tick all three boxes to always get a fresh copy of the repository and to update the repository when launching a job.

• Click SAVE

The new Project will be synced automatically after creation. But you can also do this automatically: Sync the Project again with the Git repository by going to the Projects view and clicking the circular arrow Get latest SCM revision icon to the right of the Project.

After starting the sync job, go to the Jobs view: there is a new job for the update of the Git repository.

Create a Job Template and Run a Job

A job template is a definition and set of parameters for running an Ansible job. Job templates are useful to execute the same job many times. So before running an Ansible Job from Tower you must create a Job Template that pulls together:

• Inventory: On what hosts should the job run?

• Credentials What credentials are needed to log into the hosts?

• Project: Where is the Playbook?

• What Playbook to use?

Okay, let’s just do that: Go to the Templates view, click the button and choose Job Template.

Tip

Remember that you can often click on magnfying glasses to get an overview of options to pick to fill in fields.

• NAME: Install Apache

• JOB TYPE: Run

• INVENTORY: Workshop Inventory

• PROJECT: Ansible Workshop Examples

• PLAYBOOK: rhel/apache/apache_install.yml

• CREDENTIAL: Workshop Credentials

• We need to run the tasks as root so check Enable privilege escalation

• Click SAVE

You can start the job by directly clicking the blue LAUNCH button, or by clicking on the rocket in the Job Templates overview. After launching the Job Template, you are automatically brought to the job overview where you can follow the playbook execution in real time:

Since this might take some time, have a closer look at all the details provided:

• All details of the job template like inventory, project, credentials and playbook are shown.

• Additionally, the actual revision of the playbook is recorded here - this makes it easier to analyse job runs later on.

• Also the time of execution with start and end time is recorded, giving you an idea of how long a job execution actually was.

• On the right side, the output of the playbook run is shown. Click on a node underneath a task and see that detailed information are provided for each task of each node.

After the Job has finished go to the main Jobs view: All jobs are listed here, you should see directly before the Playbook run an SCM update was started. This is the Git update we configured for the Project on launch!

Challenge Lab: Check the Result

Time for a little challenge:

• Use an ad hoc command on both hosts to make sure Apache has been installed and is running.

You have already been through all the steps needed, so try this for yourself.

Tip

What about systemctl status httpd?

Warning

Solution Below

• Go to Inventories → Workshop Inventory

• In the HOSTS view select all hosts and click RUN COMMANDS

• MODULE: command

• ARGUMENTS: systemctl status httpd

• MACHINE CREDENTIALS: Workshop Credentials

• Click LAUNCH

What About Some Practice?

Here is a list of tasks:

Warning

Please make sure to finish these steps as the next chapter depends on it!

• Create a new inventory called Webserver and make only node1 member of it.

• Copy the Install Apache template using the copy icon in the Templates view

• Change the name to Install Apache Ask

• Change the INVENTORY setting of the Project so it will ask for the inventory on launch

• SAVE

• Launch the Install Apache Ask template.

• It will now ask for the inventory to use, choose the Webserver inventory and click LAUNCH

• Wait until the Job has finished and make sure it run only on node1

Tip

The Job didn’t change anything because Apache was already installed in the latest version.

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