2.6-workflows

Workshop Exercise - Workflows

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Table Contents

• Objective
• Guide
  • Lab scenario
  • Set up projects
  • Set up job templates
  • Set up the workflow
  • Launch workflow

Objective

The basic idea of a workflow is to link multiple Job Templates together. They may or may not share inventory, playbooks or even permissions. The links can be conditional:

• if job template A succeeds, job template B is automatically executed afterwards
• but in case of failure, job template C will be run.

And the workflows are not even limited to Job Templates, but can also include project or inventory updates.

This enables new applications for Ansible automation controller: different Job Templates can build upon each other. E.g. the networking team creates playbooks with their own content, in their own Git repository and even targeting their own inventory, while the operations team also has their own repos, playbooks and inventory.

In this lab you’ll learn how to setup a workflow.

Guide

Lab scenario

You have two departments in your organization:

• The web operations team that is developing playbooks in their own Git branch named webops
• The web developers team that is developing playbooks in their own Git branch named webdev.

When there is a new Node.js server to deploy, two things need to happen:

Web operations team

• httpd, firewalld, and node.js need to be installed, SELinux settings configured, the firewall needs to be opened, and httpd and node.js should get started.

Web developers team

• The most recent version of the web application needs to be deployed and node.js needs to be restarted.

In other words, the Web operations team prepares a server for application deployment, and the Web developers team deploys the application on the server.

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To make things somewhat easier for you, everything needed already exists in a Github repository: playbooks, JSP-files etc. You just need to glue it together.

Note

In this example we use two different branches of the same repository for the content of the separate teams. In reality, the structure of your Source Control repositories depends on a lot of factors and could be different.

Set up projects

First you have to set up the Git repo as a Project like you normally would.

Warning

If you are still logged in as user wweb, log out of and log in as user admin.

Within Resources -> Projects, click the Add button to create a project for the web operations team. Fill out the form as follows:

Parameter	Value
Name	Webops Git Repo
Organization	Default
Default Execution Environment	Default execution environment
Source Control Credential Type	Git
Source Control URL	https://github.com/ansible/workshop-examples.git
Source Control Branch/Tag/Commit	webops
Options	✓ Clean ✓ Delete ✓ Update Revision on Launch

Click Save

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Within Resources -> Projects, click the Add button to create a project for the web developers team. Fill out the form as follows:

Parameter	Value
Name	Webdev Git Repo
Organization	Default
Default Execution Environment	Default execution environment
Source Control Credential Type	Git
Source Control URL	https://github.com/ansible/workshop-examples.git
Source Control Branch/Tag/Commit	webdev
Options	✓ Clean ✓ Delete ✓ Update Revision on Launch

Click Save

Set up job templates

Now you have to create two Job Templates like you would for "normal" Jobs.

Within Resources -> Templates, click the Add button and choose Add job template:

Parameter	Value
Name	Web App Deploy
Job Type	Run
Inventory	Workshop Inventory
Project	Webops Git Repo
Execution Environment	Default execution environment
Playbook	rhel/webops/web_infrastructure.yml
Credentials	Workshop Credential
Limit	web
Options	✓ Privilege Escalation

Click Save

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Within Resources -> Templates, click the Add button and choose Add job template:

Parameter	Value
Name	Node.js Deploy
Job Type	Run
Inventory	Workshop Inventory
Project	Webdev Git Repo
Execution Environment	Default execution environment
Playbook	rhel/webdev/install_node_app.yml
Credentials	Workshop Credential
Limit	web
Options	✓ Privilege Escalation

Click Save

Tip

If you want to know what the Ansible Playbooks look like, check out the Github URL and switch to the appropriate branches.

Set up the workflow

Workflows are configured in the Templates view, you might have noticed you can choose between Add job template and Add workflow template when adding a template.

Within Resources -> Templates, click the Add button and choose Add workflow template:

Name	Deploy Webapp Server
Organization	Default

Click Save

After saving the template the Workflow Visualizer opens to allow you to build a workflow. You can later open the Workflow Visualizer again by using the button on the template details page and selecting Visualizer from the menu.

Click on the Start button, an Add Node window opens. Assign an action to the node, via node type by selecting Job Template.

Select the Web App Deploy job template and click Save.

A new node is shown, connected to the START button with the name of the job template. Hover the mouse pointer over the node, you’ll see options to add a node (+), view node details (i), edit the node (pencil), link to an available node (chain), and delete the node (trash bin).

Hover over the node and click the (+) sign to add a new node.

• For the Run Type select On Success (default) and click Next.

Tip

The run type allows for more complex workflows. You could lay out different execution paths for successful and for failed playbook runs.

• For Node Type select Job Template (default) and choose the Node.js Deploy job template. Click Save.

  

Click Save in the top right corner of the Visualizier view.

Tip

The Visualizer has options for setting up more advanced workflows, please refer to the documentation.

Launch workflow

From within the Deploy Webapp Server Details page, Launch the workflow.

Note how the workflow run is shown in the Jobs > Deploy Webapp Server Output. In contrast to a normal job template job execution, there is no playbook output when the job completes but the time to complete the job is displayed. If you want to look at the actual playbook run, hover over the node you wish to see the details on and click it. Within the Details view of the job, select the Output menu to see the playbook output. If you want to get back the Output view of the Deploy WebappServer workflow, under Views -> Jobs -> XX - Deploy Webapp Server will take you back to the Output overview.

NOTE: Where XX is the number of the job run.

After the job was finished, check if everything worked fine: from your control host run the following curl command against node1, node2 and node3. The output of each curl command should be Hello World.

[student@ansible-1 ansible-files]$ curl http://nodeX/nodejs
Hello World

NOTE: X should be replaced with the appropriate number of the node you are checking.

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