Workshop Exercise 4.5 - Cleaning Up after the Bare Metal Application

Table of Contents

• Objective
• Step 1 - Creating a Playbook
• Step 2 - Creating a Job Tempate
• Step 3 - Running the Job Template
• Solutions

Objective

Because we’ve deployed the application without concern for security or best practices, we’re going to roll back our changes and work towards a containerized deployment approach.

In this exercise, we will create some automation to roll back the changes we’ve made and cleanup our systems.

Step 1 - Creating a Playbook

Return to your code repo and create a playbook in the playbooks directory called cleanup-bare-metal-app.yml with the following contents:

---

- name: cleanup bare metal app
  hosts:
    - all
  pre_tasks:
    - name: stop/disable all services
      ansible.builtin.systemd:
        name: ""
        state: stopped
        enabled: false
      loop:
        - ui.service
        - control.service
        - simulator.service
        - mosquitto.service
      loop_control:
        loop_var: service
  tasks:
    - name: remove files/directories
      ansible.builtin.file:
        path: ""
        state: absent
      loop:
        - /var/ui
        - /var/control
        - /var/simulator
        - /etc/mosquitto/mosquitto.conf
        - /etc/systemd/system/ui.service
        - /etc/systemd/system/control.service
        - /etc/systemd/system/simulator.service
      loop_control:
        loop_var: path
    - name: remove packages
      community.general.rpm_ostree_pkg:
        name: ""
        state: absent
      notify: reboot_system
      loop:
        - npm
        - nodejs-typescript
      loop_control:
        loop_var: package
    - name: re-enable selinux
      ansible.posix.selinux:
        state: enforcing
        policy: targeted
    - name: close firewall port
      ansible.posix.firewalld:
        port: 1881/tcp
        zone: public
        permanent: true
        state: disabled
        immediate: true
  handlers:
    - name: reboot the system
      ansible.builtin.reboot:
        reboot_command: systemctl reboot
        reboot_timeout: 300
      listen:
        - reboot_system

This playbook rolls back the changes we made previously, mainly removing the packages we installed, files we added/modified, services we created, and re-enables selinux to enforcing mode.

Remember to commit and push your code up to Gitea when finished crafting this playbook.

Step 2 - Creating a Job Template

Note

Be sure to sync your project in Controller before attempting to create this job template.

In the Controller WebUI. under Resources > Templates, select Add > Add job template and enter the following information:

Parameter	Value
Name	Cleanup Bare Metal Application
Inventory	Edge Systems
Project	Device Edge Codebase
Execution Environment	Device Edge Workshops Execution Environment
Playbook	playbooks/cleanup-bare-metal-app.yml
Credentials	✓ Device Credentials
Limit	✓ Prompt on launch
Options	✓ Privilege Escalation

Remember to click Save.

Step 3 - Running the Job Template

Now that the job template has been created, click that Launch button if still within the Cleanup Bare Metal Application Job Template. Otherwise, click the rocket ship to launch the job template from the Templates page. Enter your device name when prompted within the limit dialog. Monitor the output for any errors or issues. Hopefully the job executes successfully.

As a reminder, the output of jobs can be reviewed on the Jobs tab.

Once the playbook completes, you should no longer be able to access the application as it has been uninstalled.

Solutions

Our systems are now back to a known good, clean state where we can start our deployment again.

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