Ephemeral Github Runner Ansible role

This ansible role installs and configures rootless docker and a self-hosted ephemeral github runner in a secure way.

Scripts used used in this for the runner service are from @alvicsam and his github-runner-docker-ephemeral repo. By default with the docker-github-actions-runner setup variables are not safe from exfiltration. Read his blogpost for more information.

### Security

It is known that environment variables are not safe from
exfiltration. If you are using this runner make sure that any
workflow changes are gated by a verification process (in the actions
settings) so that malicious PR's cannot exfiltrate these.

To solve this we are using @alvicsam's solution and are going to run another docker container in parallel, which will be run in a rootless docker setup.

Role Requirements

---

This role currently only supports Debian (and Ubuntu).

requirements.yml

---
roles:
  - name: github-runner-ephemeral
    src: https://github.com/ibp-network/ansible-role-github-runner-ephemeral.git
    scm: git
    version: main

ansible-galaxy install -r requirements.yml

Using the Role

---

Playbook Example

---
- name: Github Playbook
  hosts: github_runner
  gather_facts: true
  roles:
    - role: github-runner-ephemeral

Inventory Example

---
all:
  children:
    github_runner:
      hosts:
        git1:
          ansible_host: gitrun-001.amforc.com
          runner_name: ibp-ch
          runner_org: amforc
          runner_app_id: "{{runner_app_id}}"
          runner_app_login: "{{runner_app_login}}"
          runner_app_private_key: "{{runner_app_private_key}}"

Vault Example

---
runner_app_id: 12345
runner_app_login: amforc

runner_app_private_key: |
  -----BEGIN RSA PRIVATE KEY-----
  -----END RSA PRIVATE KEY-----

Variables

---

The following are the ones that have to be set

Variable	Description	Value
runner_name	The name of the ephemeral runner, this will show up in the org in github.	use ibp-xx where xx is your ISO code
runner_org	The github organisation this runner will join.	please request this
runner_app_id	The github application ID.	please request this
runner_app_login	The github application login id. If not specified, the same value as runner_org can be used	please request this
runner_app_private_key	The github application private key	please request this

Some of the default ones, can be changed to your needs

Variable	Default	Description
runner_scope	org	The scope the runner will be registered on
runner_labels	self-hosted,ephemeral,ubuntu,ubuntu-latest	A comma separated string to indicate the labels.
runner_build	myoung34/github-runner:ubuntu-noble	Using Ubuntu 24.04 by default, More options here

Creating a Github app

---

If a project wants a ephemeral runner, run by the IBP they first need to create a Github app and provide runner_app_id, runner_app_login, runner_app_private_key to the IBP member that will run their instance.

• Go to: Github > org > settings > developer settings > github apps > new github app
  • Enter name
  • Homepage url can be any place holder
  • callback url can be left empty
  • webhook false
  • Organization permissions: Self-hosted runners Read & Write
  • Where can this GitHub App be installed?: Only on this account
  • create
• copy the app id
• Go to private keys, generate a new one.
• Go to Install App and install ap in org.

Send all the new necessary information in a secure matter to the IBP member that will run your instance.