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Ansible Lab exercises

Workshop Exercise - Wrap up

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Objective

This is the final challenge where we try to put most of what you have learned together.

Guide

Let’s set the stage

Your operations team and your application development team likes what they see in Ansible Tower. To really use it in their environment they put together these requirements:

All webservers (node1, node2 and node3) should go in one group
As the webservers can be used for development purposes or in production, there has to be a way to flag them accordingly as “stage dev” or “stage prod”.
- Currently node1 and node3 are used as a development system and node2 is in production.
Of course the content of the world famous application “index.html” will be different between dev and prod stages.
- There should be a title on the page stating the environment
- There should be a content field
The content writer wweb should have access to a survey to change the content for dev and prod servers.

The Git Repository

All code is already in place - this is a Tower lab after all. Check out the Workshop Project git repository at https://github.com/ansible/workshop-examples. There you will find the playbook webcontent.yml, which calls the role role_webcontent.

Compared to the previous Apache installation role there is a major difference: there are now two versions of an index.html template, and a task deploying the template file which has a variable as part of the source file name:

dev_index.html.j2

<body>
<h1>This is a development webserver, have fun!</h1>
{{ dev_content }}
</body>

prod_index.html.j2

<body>
<h1>This is a production webserver, take care!</h1>
{{ prod_content }}
</body>

main.yml

[...]
- name: Deploy index.html from template
  template:
    src: "{{ stage }}_index.html.j2"
    dest: /var/www/html/index.html
  notify: apache-restart

Prepare Inventory

There is of course more then one way to accomplish this, but here is what you should do:

Make sure all hosts are in the inventory group Webserver.
Define a variable stage with the value dev for the Webserver inventory:
- Add stage: dev to the inventory Webserver by putting it into the VARIABLES field beneath the three start-yaml dashes.
In the same way add a variable stage: prod but this time only for node2 (by clicking the hostname) so that it overrides the inventory variable.

Tip

Make sure to keep the three dashes that mark the YAML start and the ansible_host line in place!

Create the Template

Create a new Job Template named Create Web Content that
- targets the Webserver inventory
- uses the Playbook rhel/apache/webcontent.yml from the Workshop Project Project
- Defines two variables: dev_content: default dev content and prod_content: default prod content in the EXTRA VARIABLES FIELD
- Uses Workshop Credentials and runs with privilege escalation
Save and run the template

Check the results

This time we use the power of Ansible to check the results: execute curl to get the web content from each node, orchestrated by an ad-hoc command on the command line of your Tower control host:

Tip

We are using the ansible_host variable in the URL to access every node in the inventory group.

[user@control ~]$ ansible web -m command -a "curl -s http://{{ ansible_host }}"
 [WARNING]: Consider using the get_url or uri module rather than running 'curl'.  If you need to use command because get_url or uri is insufficient you can add 'warn: false' to this command task or set 'command_warnings=False' in ansible.cfg to get rid of this message.

node2 | CHANGED | rc=0 >>
<body>
<h1>This is a production webserver, take care!</h1>
prod wweb
</body>

node1 | CHANGED | rc=0 >>
<body>
<h1>This is a development webserver, have fun!</h1>
dev wweb
</body>

node3 | CHANGED | rc=0 >>
<body>
<h1>This is a development webserver, have fun!</h1>
dev wweb
</body>

Note the warning in the first line about not to use curl via the command module since there are better modules right within Ansible. We will come back to that in the next part.

Add Survey

Add a survey to the Template to allow changing the variables dev_content and prod_content
Add permissions to the Team Web Content so the Template Create Web Content can be executed by wweb.
Run the survey as user wweb

Check the results again from your Tower control host. Since we got a warning last time using curl via the command module, this time we will use the dedicated uri module. As arguments it needs the actual URL and a flag to output the body in the results.

[useransible ~]$ ansible web -m uri -a "url=http://{{ ansible_host }}/ return_content=yes"
node3 | SUCCESS => {
    "accept_ranges": "bytes",
    "ansible_facts": {
        "discovered_interpreter_python": "/usr/bin/python"
    },
    "changed": false,
    "connection": "close",
    "content": "<body>\n<h1>This is a development webserver, have fun!</h1>\nwerners dev content\n</body>\n",
    "content_length": "87",
    "content_type": "text/html; charset=UTF-8",
    "cookies": {},
    "cookies_string": "",
    "date": "Tue, 29 Oct 2019 11:14:24 GMT",
    "elapsed": 0,
    "etag": "\"57-5960ab74fc401\"",
    "last_modified": "Tue, 29 Oct 2019 11:14:12 GMT",
    "msg": "OK (87 bytes)",
    "redirected": false,
    "server": "Apache/2.4.6 (Red Hat Enterprise Linux)",
    "status": 200,
    "url": "http://18.205.236.208"
}
[...]

Solution

Warning

Solution Not Below

You have done all the required configuration steps in the lab already. If unsure, just refer back to the respective chapters.

The End

Congratulations, you finished your labs! We hope you enjoyed your first encounter with Ansible Tower as much as we enjoyed creating the labs.

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