HashiTalks 2022 - OIDC configuration with Hashi Vault

OIDC configuration with Hashi Vault.md

Setup

Configure Vault

Start Vault:

vault server -dev

Enable JWT auth mechanism:

vault auth enable jwt

Configure jwt auth with oidc discovery URL:

vault write auth/jwt/config \
	oidc_discovery_url="https://token.actions.githubusercontent.com" \
	bound_issuer="https://token.actions.githubusercontent.com" \
	default_role="github-action"

Create a role for jwt authentication:

vault write auth/jwt/role/github-action \
	bound_subject="repo:alwell-kevin/code-to-cloud-twitch:ref:refs/heads/main" \
	bound_audiences="https://github.com/alwell-kevin" \
	user_claim="sub" \
	policies="ci" \
	ttl=10m \
	role_type="jwt"

Note: ttl defines the validity of client_token.Change this if longer validity for token is needed.

Edit ci policy to allow access to CI:

# ci-policy.hcl
path "secret/data/ci" {
  capabilities = [ "read" ]
}

Write the policy:

vault policy write ci ci-policy.hcl

Add secret:

vault kv put secret/ci npmToken=StresseD

Configure GitHub Actions self hosted runner

Configure and start a self hosted runner:

# ...configuration according to instructions...

./run.sh

Retrive the secret from an Actions workflow

on:
  workflow_dispatch:

name: Retrieve Vault Secret

jobs:
  build:
    runs-on: self-hosted
    permissions:
      id-token: write
      contents: read

    steps:

    # Use official HashiCorp Vault action, directing it to retrieve the `npmToken` secret from
    # the local endpoint using the role configured previously.
    - uses: hashicorp/[email protected]
      with:
        url: 'http://127.0.0.1:8200'
        method: jwt
        role: github-action
        secrets: secret/data/ci npmToken

    # Use the secret (echo for validation, in this case). By default, the secret is written to an 
    # environment variable with the same name as the secret. 
    # https://github.com/hashicorp/vault-action#set-output-variable-name
    - run: |
        echo $NPMTOKEN | rev

Special Shout out to @imjohnbo for making this possible!