hc-vault-testing

Testing HashiCorp Vault functionality

Objectives

Goal of this repository is to provide an environment to demonstrate and test initial secret introduction in a Linux environment, using HashiCorp Vault, and Consul-template on a local node.

Architecture

The Vagrantfile can spin up a single node running Vault with a simple example application.

This is a minimal environment without high availability or TLS enabled purely to test Vault AppRole functionality for managing the initial secret (token) introduction.

Vault AppRole Testing

Summary

One of Vault's use cases is to obtain secrets for use within an application on a server. A node can authenticate with Vault using a token to obtain the required secrets, but a secure introduction of that authenticating token is still required. AppRole functionality is one method of obtaining that token.

Overview

The below are end to end steps on using AppRole (pull method) for managing your secret introduction. This process is flexible and open to various interpretations based on environment constraints, and various tools used.

Enable AppRole on Vault
Write secrets
Create policy mapping specific AppRole 'foo' to secrets
Create specific AppRole 'foo', associated with policy, and other constraints (bound CIDR list allowed for login requests, secret_id number uses, secret_id ttl, etc)
Read role_id for AppRole 'foo'. This is a long lasting role identifier for this AppRole (foo). Akin to an email address or user ID. This information is not sensitive in and of itself, but you would not want to share it publicly.
Embed the role_id within your operating system image. This can be done via Packer, or during provisioning steps.
Read secret_id for AppRole 'foo'. This token should be treated as sensitive, and is meant to be short lived. Using response wrapping here is a good idea as it protects the secret_id during the delivery process.
Deploy the secret_id during orchestration activities (during application deployment, configuration management or some steps post provisioning). An example might be a deploy using an orchestrator capable of API calls, with the first step being the retrieval of the secret_id from Vault.
Use a script or process that performs the login operation that makes a request to Vault combining role_id + secret_id to obtain a token. This script should also perform maintenance of the token, ensuring it is renewed on a regular basis. I have an example shell script at scripts/vault-approle-token.sh that can be executed via systemd that can perform this process.
Consul-template or envconsul can now use the obtained token to make requests to Vault for secrets.

TODO:

Finish and test vault-approle-token.sh script
Setup systemd to run vault-approle-token.sh as a service

Scripts

Scripts used in this repository

./vault-approle-setup.sh   # this configures approle and generates role_id and secret_id
./vault-approle-token.sh   # this is a script that maintains a token on a system to be used by consul-template, envconsul and so forth
./vault-cleanup.sh         # restarts and reinitializes Vault, clears artifacts - startover from scratch

Usage

To bring up the Ubuntu vm

vagrant up

To test AppRole

vagrant ssh
/vagrant/vault-approle-setup.sh
/vagrant/vault-approle-token.sh

Current Status

The above usage steps work. Items to be completed:

Token management script needs to be managed by systemd
Script logic calculating token renewal period needs to be completed.
Need to complete AppRole push example

Token management script logic


          +-------------------+
          | does token exist? |
          +-------------------+
  +----+           |         +------+
  | no +---------------------+  yes |
  +----+                     +------+
     |                           |
     |                           |
  +-----------------+            |
  |does role_id and |            |
  |secret_id exist? |            |
  +-----------------+            |
           |                     |
  +----+   |         +-----+     |
  | no +-------------+ yes |     |
  +----+             +-----+     |
     |                   |       |
     |                   |       |
  +-----------------+    |       |
  |wait for role_id |    |       |
  |and secret_id    |    |       |
  +-----------------+    |       |
          |              |       |
  +-------------------------+    |
  |   fetch token           |    |
  +-------------------------+    |
          |                      |
          |                 +-------------+
          |                 | renew token |
          |                 +-------------+
          |                      |
          |                      |
  +-----------------------------------+
  |exit and let systemd trigger       |
  |periodic token renewal             |
  +-----------------------------------+

systemd timer notes https://www.freedesktop.org/software/systemd/man/systemd.timer.html Note that in case the unit to activate is already active at the time the timer elapses it is not restarted, but simply left running. There is no concept of spawning new service instances in this case. Due to this, services with RemainAfterExit= set (which stay around continuously even after the service's main process exited) are usually not suitable for activation via repetitive timers, as they will only be activated once, and then stay around forever. https://www.certdepot.net/rhel7-use-systemd-timers/ https://jason.the-graham.com/2013/03/06/how-to-use-systemd-timers/ https://wiki.archlinux.org/index.php/Systemd/Timers

AppRole pull configuration (TODO)

vagrant ssh
cd /vagrant/scripts
./vault-approle-setup.sh
./vault

greenbrian / hc-vault-testing