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Continues work on session material for day 27
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Daniel Bodky
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2024/day27.md
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2024/day27.md
@ -15,185 +15,85 @@ This presentation will give a broad overview of Ansible and its architecture and
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Participants will get first-hand insights into Ansible, its strengths, weaknesses, and the potential of event-driven automation within the DevOps world.
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## Demos
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> [!NOTE]
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> The below content is a copy of the [lab repository's] README for convenience.
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<details>
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---
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<summary>Prerequisites</summary>
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# Event-Driven Ansible Lab
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### Ansible Inventory
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This is a lab designed to demonstrate Ansible and how Event-Driven Ansible (**EDA**) builds on top of its capabilities.
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The setup is done with Ansible, too. It will install **Ansible, EDA, Prometheus**, and **Alertmanager** on a VM to demonstrate some of the capabilities of EDA.
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## Prerequisites
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To follow along with this lab in its entirety, you will need four VMs:
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> [!NOTE]
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> For this inventory file to work, you need to create VMs accordingly and adjust the IP addresses to fit your lab environment.
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> If you want to skip Ansible basics and go straight to EDA, you'll need just the `eda-controller.example.com` VM and can skip the others.
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Ansible utilizes so-called inventories to manage a list of hosts and groups of hosts. Below is the inventory for the demo environment used in this presentation.
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| VM name | OS |
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|--------------------|-------------|
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| eda-controller.example.com | CentOS/Rocky 8.9 |
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| company.example.com | CentOS/Rocky 8.9 |
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| internal.example.com | Ubuntu 22.04 |
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| webshop.example.com | OpenSUSE 15.5 |
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```yaml
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hosts:
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webservers:
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hosts:
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webshop.example.com: # Ubuntu
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ansible_host: 192.168.1.10
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webserver: apache2
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company.example.com: # Ubuntu
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ansible_host: 192.168.1.11
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webserver: nginx
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internal.example.com: # CentOS Stream
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ansible_host: 192.168.1.12
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webserver: httpd
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**You'll need to be able to SSH to each of these VMs as root using SSH keys.**
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## Lab Setup
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### Clone the repository and create a Python virtual environment
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```bash
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git clone https://github.com/mocdaniel/lab-event-driven-ansible.git
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cd lab-event-driven-ansible
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python3 -m venv .venv
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source .venv/bin/activate
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```
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You can copy-paste this inventory into a file called `hosts.yml` and use it for the following demos.
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### Install Ansible and other dependencies
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</details>
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<details>
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<summary>Lab 1: Ansible Basics</summary>
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### Demo 1: Ansible Basics
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#### Ansible from the CLI via `ansible`
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The first example installs a webserver on all hosts in the `webservers` group. The installed webserver is defined as a **host variable** in the inventory file `hosts.yml` (*see above*).
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```console
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ansible \
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webservers \
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-i hosts.yml \
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-m package \
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-a 'name="{{ webserver }}"'
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```bash
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pip install -r requirements.txt
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```
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#### Ansible from the CLI via `ansible-playbook`
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The second example utilizes the following **playbook** to **install** and **start** the defined webserver on all hosts in the `webservers` group.
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### Create the inventory file
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```yaml
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---
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- name: Install webservers
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hosts: webservers
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vars:
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package: "{{ webserver }}"
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become: true
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tasks:
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- name: Install webserver
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ansible.builtin.package:
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name: "{{ package }}"
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state: present
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- name: Start webserver
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ansible.builtin.service:
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name: "{{ package }}"
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state: started
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# hosts.yml
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webservers:
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hosts:
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webshop.example.com:
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ansible_host: <ip-address>
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webserver: nginx
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company.example.com:
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ansible_host: <ip-address>
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webserver: httpd
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internal.example.com:
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ansible_host: <ip-address>
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webserver: apache2
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eda_controller:
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hosts:
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eda-controller.example.com:
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ansible_host: <ip-address>
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```
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Save this playbook as `playbook.yml` and run it with the following command.
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```console
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ansible-playbook \
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-i hosts.yml \
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playbook.yml
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### Install Needed Roles and Collections
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```bash
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ansible-galaxy install -r requirements.yml
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```
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You will see a separated output for each task in the playbook. In the end, you should be able to access the webserver on each host in the `webservers` group.
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### Run the Setup Playbook
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> [!TIP]
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> Ansible is **idempotent** - try running the playbook again and see how the output differs.
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After you created the inventory file and filled in the IP addresses, you can run the setup playbook:
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</details>
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<details>
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<summary>Lab 2: Event-driven Ansible and Generic Webhooks</summary>
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### Demo 2: Event-driven Ansible and Generic Webhooks
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#### Prerequisites
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For this demo, we will use `localhost` as the target host. Therefore, we need to adjust our inventory file `hosts.yml` accordingly:
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```yaml
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hosts:
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localhost: {}
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The first demo of event-driven Ansible shows how to use a generic webhook to trigger a playbook run. Copy the following rulebook into a file called `rulebook.yml`.
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```yaml
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- name: Listen to webhook events
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hosts: all
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sources:
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- ansible.eda.webhook:
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host: 0.0.0.0
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port: 5000
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rules:
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- name: Debug event output
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condition: event.payload.greeting is defined
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action:
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debug:
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msg: "Hello {{ event.payload.greeting }}!"
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- name: Greet stranger
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condition: 1 == 1 # default case
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action:
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debug:
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msg: Hello World!
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```bash
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ansible-playbook playbooks/setup.yml
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```
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#### Start the EDA server
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To start the EDA server, run the following command.
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```console
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ansible-rulebook \
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-i hosts.yml \
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--rulebook rulebook.yml
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```
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#### Trigger the webhook
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Once the EDA server is running, we can open a second terminal session and double-check that it is listening on the correct port:
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```console
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netstat -lntup | grep 5000
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```
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Now, we can trigger the webhook from our second terminal session using `curl`, first with empty input:
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```console
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curl \
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-H "Content-Type: application/json" \
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-d '{}' \
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http://localhost:5000/endpoint
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```
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If we switch over to the first terminal session, we should see the output of the second rule, which is the default case:
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```console
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Hello World!
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```
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Now, we can trigger the webhook again, this time with a payload:
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```console
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curl \
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-H "Content-Type: application/json" \
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-d '{"greeting": "Daniel"}' \
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http://localhost:5000/endpoint
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```
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If we switch over to the first terminal session again, we should see the output of the first rule, which is the case for a defined `greeting` in the payload:
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```console
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Hello Daniel!
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```
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</details>
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## Resources
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- [Ansible Documentation](https://docs.ansible.com/)
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- [Installing Ansible](https://docs.ansible.com/ansible/latest/installation_guide/intro_installation.html#installing-and-upgrading-ansible)
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- [Ansible Galaxy](https://galaxy.ansible.com/)
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- [EDA Documentation](https://ansible.readthedocs.io/projects/rulebook/en/stable/introduction.html)
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- [Installing and Running EDA](https://ansible.readthedocs.io/projects/rulebook/en/stable/installation.html)
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> [!CAUTION]
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> Due to a known bug with Python on MacOS, you need to run `export NO_PROXY="*"` on MacOS before running the playbook
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