--- layout: guides page_title: AppRole With Terraform & Chef - Guides sidebar_title: AppRole with Terraform and Chef description: |- This guide discusses the concepts necessary to help users understand Vault's AppRole authentication pattern and how to use it to securely introduce a Vault authentication token to a target server, application, container, etc.x --- # Vault AppRole with Terraform and Chef Demo In the [AppRole Pull Authentication](/guides/identity/authentication#advanced-features) guide, the question of how best to deliver the Role ID and Secret ID were brought up, and the role of trusted entities (Terraform, Chef, Nomad, Kubernetes, etc.) was mentioned. ![AppRole auth method workflow](/img/vault-approle-workflow2.png) This _intermediate_ Vault guide aims to provide a **simple**, **end-to-end** example of how to use Vault's [AppRole authentication method](/docs/auth/approle), along with Terraform and Chef, to address the challenge of the **_secure introduction_** of an initial token to a target system. The purpose of this guide is to provide the instruction to reproduce the working implementation demo introduced in the [Delivering Secret Zero: Vault AppRole with Terraform and Chef](https://www.hashicorp.com/resources/delivering-secret-zero-vault-approle-terraform-chef) webinar. [![YouTube](/img/vault-approle-youtube.png)](https://youtu.be/OIcIzFWjThM) -> **NOTE:** This is a proof of concept and **NOT SUITABLE FOR PRODUCTION USE**. ## Reference Material - [AppRole Auth Method](/docs/auth/approle) - [Authenticating Applications with HashiCorp Vault AppRole](https://www.hashicorp.com/blog/authenticating-applications-with-vault-approle) - [Delivering Secret Zero: Vault AppRole with Terraform and Chef](https://www.hashicorp.com/resources/delivering-secret-zero-vault-approle-terraform-chef) ## Estimated Time to Complete 20 minutes ## Challenge The goal of the AppRole authentication method is to provide a mechanism for the secure introduction of secrets to target systems (servers, applications, containers, etc.). The question becomes what systems within our environment do we trust to handle or deliver the `RoleID` and `SecretID` to our target systems. ## Solution Use _Trusted Entities_ to deliver the AppRole authentication values. For example, use Terraform to deliver your `RoleID` or embed it into your AMI or Dockerfile. Then you might use Jenkins or Chef to obtain the [response-wrapped](/guides/secret-mgmt/cubbyhole) `SecretID` and deliver it to the target system. AppRole allows us to securely introduce the authentication token to the target system by preventing any single system from having full access to an authentication token that does not belong to. This helps us maintain the security principles of **least privilege** and **non-repudiation**. The important thing to note here is that regardless of what systems are considered as _Trusted Entities_, the same pattern applies. For example: - With Chef, you might use the [Vault Ruby Gem](https://github.com/hashicorp/vault-ruby) for simplified interaction with Vault APIs - Terraform provides a Vault provider: [Provider: Vault - Terraform by HashiCorp](https://www.terraform.io/docs/providers/vault/index.html) - For Jenkins, you might use the Vault CLI or APIs directly, as described here: [Reading Vault Secrets in your Jenkins pipeline](http://nicolas.corrarello.com/general/vault/security/ci/2017/04/23/Reading-Vault-Secrets-in-your-Jenkins-pipeline.html) ## Prerequisites This guide assumes that you are proficient enough to perform basic Terraform tasks. If you are not familiar with Terraform, refer to the [online documentation](https://www.terraform.io/intro/getting-started/install.html). The following AWS resources are required to perform this demo: - An [Amazon S3 bucket](https://docs.aws.amazon.com/AmazonS3/latest/gsg/CreatingABucket.html) - An [IAM user credential with administrator permissions](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_users_change-permissions.html) (to be able to create additional IAM policies and instance profiles) ### Download demo assets Clone or download the demo assets from the [hashicorp/vault-guides](https://github.com/hashicorp/vault-guides/tree/master/identity/vault-chef-approle) GitHub repository to perform the steps described in this guide. The following assets can be found in the repository: - Chef cookbook (**`/chef/cookbooks`**): A sample cookbook with a recipe that installs NGINX and demonstrates Vault Ruby Gem functionality used to interact with Vault APIs. - Terraform configurations (**`/terraform-aws`**): - **`/terraform-aws/mgmt-node`**: Configuration to set up a management server running both Vault and Chef Server, for demo purposes. - **`/terraform-aws/chef-node`**: Configuration to set up a Chef node and bootstrap it with the Chef Server, passing in Vault's AppRole RoleID and the appropriate Chef run-list. - Vault configuration (**`/scripts`**): Data scripts used to configure the appropriate mounts and policies in Vault for this demo. ## Steps The scenario in this guide uses Terraform and Chef as trusted entities to deliver `RoleID` and `SecretID`. ![AppRole auth method workflow](/img/vault-approle-tf-chef.png) For the simplicity of the demonstration, both Vault and Chef are installed on the same node. Terraform provisions the node which contains the `RoleID` as an environment variable. Chef pulls the `SecretID` from Vault. Provisioning for this demo happens in 2 phases: - [Phase 1 - Provision our Vault plus Chef Server](#phase1) - [Step 1: Provision the Vault and Chef Server](#step-1-provision-the-vault-and-chef-server) - [Step 2: Initialize and Unseal Vault](#step-2-initialize-and-unseal-vault) - [Step 3: AppRole Setup](#step-3-approle-setup) - [Step 4: Configure Tokens for Terraform and Chef](#step-4-configure-tokens-for-terraform-and-chef) - [Step 5: Save the Token in a Chef Data Bag](#step-5-save-the-token-in-a-chef-data-bag) - [Step 6: Write Secrets](#step-6-write-secrets) - [Phase 2 - Provision our Chef Node to Show AppRole Login](#phase2) ## Phase 1: Provision our Vault & Chef Server ((#phase1)) ### Step 1: Provision the Vault and Chef Server This provides a quick and simple Vault and Chef Server configuration to help you get started. **NOTE:** This is done for demonstration purpose and **NOT a recommended practice** for production. In this phase, you use Terraform to spin up a server (and associated AWS resources) with both Vault and Chef Server installed. Once this server is up and running, you'll complete the appropriate configuration steps in Vault to set up our AppRole and tokens for use in the demo. ~> If using _Terraform Enterprise_, [create a Workspace](https://www.terraform.io/docs/enterprise/getting-started/workspaces.html) for this repo and set the appropriate Terraform/Environment variables using the `terraform.tfvars.example` file as a reference. Follow the instructions in the documentation to perform the appropriate setup in Terraform Enterprise. #### Using Terraform Open Source: **Task 1:** Change the working directory (`cd`) to `identity/vault-chef-approle/terraform-aws/mgmt-node`. ```shell . ├── main.tf ├── outputs.tf ├── templates │   └── userdata-mgmt-node.tpl ├── terraform.tfvars.example └── variables.tf ``` **Task 2:** Update the `terraform.tfvars.example` file to match your account and rename it to `terraform.tfvars`. At minimum, replace the following variable with appropriate values: - **`s3_bucket_name`** - **`vpc_id`** - **`subnet_id`** - **`key_name`** - **`ec2_pem`** > NOTE: If your VPC, subnet and EC2 key pair were created on a region other than > `us-east-1`, be sure to set the **`aws_region`** value to match your chosen region. **Task 3:** Perform a `terraform init` to pull down the necessary provider resources. Then `terraform plan` to verify your changes and the resources that will be created. If all looks good, then perform a `terraform apply` to provision the resources. The Terraform output will display the public IP address to SSH into your server. ```shell-session $ terraform init Initializing provider plugins... ... Terraform has been successfully initialized! $ terraform plan ... Plan: 5 to add, 0 to change, 0 to destroy. $ terraform apply ... Apply complete! Resources: 5 added, 0 changed, 0 destroyed. Outputs: vault-public-ip = 192.0.2.0 ``` The Terraform output will display the public IP address to SSH into your server. For example: ```shell-session $ ssh -i "/path/to/EC2/private_key.pem" ubuntu@192.0.2.0 ``` **Task 4:** Initial setup of the Chef server takes several minutes. Once you can SSH into your mgmt server, run `tail -f /var/log/tf-user-data.log` to see when the initial configuration is complete. ```shell-session $ tail -f /var/log/tf-user-data.log ``` When you see the following message, the initial setup is complete. ```plaintext + echo '2018/03/27 21:53:06 /var/lib/cloud/instance/scripts/part-001: Complete' ``` You can find the following subfolders in your home directory: - **`/home/ubuntu/vault-chef-approle-demo`**: root of our project - **`/home/ubuntu/vault-chef-approle-demo/chef`**: root of our Chef app; this is where our `knife` configuration is located (`.chef/knife.rb`) - **`/home/ubuntu/vault-chef-approle-demo/scripts`**: there's a `vault-approle-setup.sh` script located here to help automate the setup of Vault, or you can follow along in the rest of this README to configure Vault manually ### Step 2: Initialize and Unseal Vault Before moving on, set your working environment variables in your mgmt server: ```shell-session $ export VAULT_ADDR=http://127.0.0.1:8200 $ export VAULT_SKIP_VERIFY=true ``` Before you can do anything in Vault, you need to initialize and unseal it. Perform **_one_** of the following: - **Option 1:** Run the `/home/ubuntu/demo_setup.sh` script to get up and running, and proceed to [Phase 2 - Provision our Chef Node to Show AppRole Login](#phase2). - **Option 2:** Continue onto [Step 3: AppRole Setup](#step-3-approle-setup) to set up the demo environment **_manually_**. ### Step 3: AppRole Setup First, initialize and unseal the Vault server using a shortcut. ~> This is a convenient shortcut for demo. **_DO NOT DO THIS IN PRODUCTION!!!_** Refer to the [online documentation for initializing and unsealing](/intro/getting-started/deploy#initializing-the-vault) Vault for more details. ```shell # Initialize the Vault server and write out the unseal keys and root token into files $ curl --silent --request PUT \ --data '{"secret_shares": 1, "secret_threshold": 1}' \ ${VAULT_ADDR}/v1/sys/init | tee \ >(jq -r .root_token > /home/ubuntu/vault-chef-approle-demo/root-token) \ >(jq -r .keys[0] > /home/ubuntu/vault-chef-approle-demo/unseal-key) # Unseal vault $ vault operator unseal $(cat /home/ubuntu/vault-chef-approle-demo/unseal-key) # Set the root token to VAULT_TOKEN env var $ export VAULT_TOKEN=$(cat /home/ubuntu/vault-chef-approle-demo/root-token) ``` In the next few steps, you will create a number of policies and tokens within Vault. Below is a table that summarizes them: | Policy | Description | Token Attachment | | ------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------- | | `app-1-secret-read` | Sets the policy for the final token that will be delivered via the AppRole login | None. This will be delivered to the client upon AppRole login | | `app-1-approle-roleid-get` | Sets the policy for the token that you'll give to Terraform to deliver the RoleID (only) | `roleid-token` | | `terraform-token-create` | The Terraform Vault provider doesn't use the token supplied to it directly. This is to prevent the token from being exposed in Terraform's state file. Instead, the Token given to Terraform needs to have the capability to create child tokens with short TTLs. See [here](https://www.terraform.io/docs/providers/vault/index.html#token) for more info | `roleid-token` | | `app-1-approle-secretid-create` | Sets the policy for the token that you'll store in the Chef Data Bag. This will only be able to pull our AppRole's SecretID | `secretid-token` | These setups only need to be performed upon initial creation of an AppRole, and would typically be done by a Vault administrator. Now that you have your Vault server unsealed, you can begin to set up necessary policies, AppRole auth method, and tokens. #### Task 1: Set up our AppRole policy This is the policy that will be attached to _secret zero_ which you are delivering to our application (**app-1**). **API call using cURL** ```bash # Policy to apply to AppRole token $ tee app-1-secret-read.json < roleid-token.json ``` The token and associated metadata will be written out to the file `roleid-token.json`. The `client_token` value is what you'll give to Terraform. The file should look similar to the following: ```shell-session $ cat roleid-token.json | jq { "request_id": "2e1d05eb-988d-4cf7-7b6a-d2668de31536", "lease_id": "", "renewable": false, "lease_duration": 0, "data": null, "wrap_info": null, "warnings": null, "auth": { "client_token": "6a7ad093-42ab-885e-3d67-6d51a5583da6", "accessor": "f6170506-ee0f-5a59-8478-e0aac2d3259f", "policies": [ "app-1-approle-roleid-get", "default", "terraform-token-create" ], "metadata": { "user": "terraform-demo" }, "lease_duration": 2592000, "renewable": true, "entity_id": "" } } ``` **CLI command** ```bash # Policy file granting to retrieve RoleID from Vault $ tee app-1-approle-roleid-get.hcl < roleid-token.txt ``` The token and associated metadata will be written out to the file `roleid-token.txt`. The `token` value is what you'll give to Terraform. The file should look similar to the following: ```shell-session $ cat roleid-token.txt Key Value --- ----- token 2600aeda-6385-c163-7171-543b1e1fabcf token_accessor 6ef835e3-4948-8c61-1e89-3625ca31fd84 token_duration 768h token_renewable true token_policies [app-1-approle-roleid-get default terraform-token-create] token_meta_user terraform-demo ``` #### Task 2: Create a policy and token for Chef Create a token with appropriate policies allowing Chef to pull the `SecretID` from Vault: **API call using cURL** ```bash # Policy file granting to retrieve SecretID $ tee app-1-approle-secretid-create.hcl < secretid-token.json ``` The resulting file should look like this: ```shell-session $ cat secretid-token.json | jq { "request_id": "6f6ad8a1-fedb-b838-60ce-87999f01aff6", "lease_id": "", "renewable": false, "lease_duration": 0, "data": null, "wrap_info": null, "warnings": null, "auth": { "client_token": "cdfdb7a0-d7a6-3769-927d-0ace297726ea", "accessor": "88e8aaca-1584-4881-3368-d9cb5cd7ddae", "policies": [ "app-1-approle-secretid-create", "default" ], "metadata": { "user": "chef-demo" }, "lease_duration": 2592000, "renewable": true, "entity_id": "" } } ``` **CLI command** ```bash # Policy file granting to retrieve SecretID $ tee app-1-approle-secretid-create.hcl < secretid-token.txt ``` The resulting file should look like this: ```shell-session $ cat secretid-token.txt Key Value --- ----- token 20d69183-59cb-c953-6dea-34f5f1bbe5f7 token_accessor a17e7a43-c14a-b96a-0014-9149d218e74a token_duration 768h token_renewable true token_policies [app-1-approle-secretid-create default] token_meta_user chef-demo ``` ### Step 5: Save the Token in a Chef Data Bag At this point, you have a client token generated for Terraform and another for Chef server to log into Vault. For the sake of simplicity, you can put the Chef's client token (`secretid-token.json`) in a [Data Bag](https://docs.chef.io/data_bags.html) which is fine because this token can **_only_** retrieve `SecretID` from Vault which is not much of a use without a corresponding `RoleID`. Now, create a Chef Data Bag and put the `SecretID` token (`secretid-token.json`) along with the rest of its metadata. ```shell-session $ cd /home/ubuntu/vault-chef-approle-demo/chef/ # Use the path for where you created this file in the previous step # You're just adding an 'id' field to the file as that's a required field for data bags $ cat /home/ubuntu/secretid-token.json | jq --arg id approle-secretid-token '. + {id: $id}' > secretid-token.json $ knife data bag create secretid-token $ knife data bag from file secretid-token secretid-token.json $ knife data bag list $ knife data bag show secretid-token $ knife data bag show secretid-token approle-secretid-token ``` The last step should show the following output: ```shell-session $ knife data bag show secretid-token approle-secretid-token WARNING: Unencrypted data bag detected, ignoring any provided secret options. auth: accessor: 88e8aaca-1584-4881-3368-d9cb5cd7ddae client_token: cdfdb7a0-d7a6-3769-927d-0ace297726ea entity_id: lease_duration: 2592000 metadata: policies: app-1-approle-secretid-create default renewable: true data: id: approle-secretid-token lease_duration: 0 lease_id: renewable: false request_id: 6f6ad8a1-fedb-b838-60ce-87999f01aff6 warnings: wrap_info: ``` ### Step 6: Write Secrets Let's write some test data in the `secret/app-1` path so that the target app will have some secret to retrieve from Vault at a later step. **API call using cURL** ```bash # Write some demo secrets $ tee demo-secrets.json <<'EOF' { "username": "app-1-user", "password": "$up3r$3cr3t!" } EOF $ curl --silent \ --location \ --header "X-Vault-Token: $VAULT_TOKEN" \ --request POST \ --data @demo-secrets.json \ $VAULT_ADDR/v1/secret/app-1 # Verify that you can read back the data: $ curl --silent \ --location \ --header "X-Vault-Token: $VAULT_TOKEN" \ --request GET \ $VAULT_ADDR/v1/secret/app-1 | jq { "request_id": "1f73c7ee-27fa-bad0-9c77-b330eef1ea88", "lease_id": "", "renewable": false, "lease_duration": 2764800, "data": { "password": "$up3r$3cr3t!", "username": "app-1-user" }, "wrap_info": null, "warnings": null, "auth": null } ``` **CLI command** ```bash # Write some demo secrets $ vault write secret/app-1 username="app-1-user" password="\$up3r\$3cr3t!" # Verify that you can read back the data: $ vault read secret/app-1 Key Value --- ----- refresh_interval 768h password $up3r$3cr3t! username app-1-user ``` -> At this point, just about all the pieces are in place. Remember, these setup steps will only need to be performed upon initial creation of an AppRole, and would typically be done by a Vault administrator. ## Phase 2: Provision our Chef Node to Show AppRole Login ((#phase2)) To complete the demo, run the **`chef-node`** Terraform configuration to see how everything talks to each other. #### Task 1: Change the working directory Open another terminal on your host machine (**not** the `mgmt-node`) and `cd` into the `identity/vault-chef-approle/terraform-aws/chef-node` directory: ```shell-session $ cd identity/vault-chef-approle/terraform-aws/chef-node ``` #### Task 2: Update terraform.tfvars.example Replace the variable values in `terraform.tfvars.example` to match your environment and save it as `terraform.tfvars` like you have done at [Step 1](#step-1-provision-the-vault-and-chef-server). Note the following: - Update the **`vault_address`** and **`chef_server_address`** variables with the IP address of our `mgmt-node` from above. - Update the **`vault_token`** variable with the `RoleID` token from **Task 1** in [Step 4](#step-4-configure-tokens-for-terraform-and-chef). - If you ran the `demo-setup.sh` script (_Option 1_), retrieve the `client_token` in the `/home/ubuntu/vault-chef-approle-demo/roleid-token.json` file: ```shell-session $ cat ~/vault-chef-approle-demo/roleid-token.json | jq ".auth.client_token" ``` #### Task 3: Run Terraform Perform a `terraform init` to pull down the necessary provider resources. Then `terraform plan` to verify your changes and the resources that will be created. If all looks good, then perform a `terraform apply` to provision the resources. The Terraform output will display the public IP address to SSH into your server. > **NOTE:** If the `terraform apply` fails with "`io: read/write on closed pipe`" > error, this is a [known > issue](https://github.com/hashicorp/terraform/issues/17638) with Terraform > 0.11.4 and 0.11.5. Please try again with another Terraform version. At this point, Terraform will perform the following actions: - Pull a `RoleID` from our Vault server - Provision an AWS instance - Write the `RoleID` to the AWS instance as an environment variable - Run the Chef provisioner to bootstrap the AWS instance with our Chef Server - Run our Chef recipe which will install NGINX, perform our AppRole login, get our secrets, and output them to our `index.html` file ![AppRole auth method workflow](/img/vault-approle-tf-chef-3.png) The Chef recipe can be found at `identity/vault-chef-approle/chef/cookbooks/vault_chef_approle_demo/recipes/default.rb`. ```shell ... # Configure address for Vault Gem Vault.address = ENV['VAULT_ADDR'] # Get AppRole RoleID from our environment variables (delivered via Terraform) var_role_id = ENV['APPROLE_ROLEID'] # Get Vault token from data bag (used to retrieve the SecretID) vault_token_data = data_bag_item('secretid-token', 'approle-secretid-token') # Set Vault token (used to retrieve the SecretID) Vault.token = vault_token_data['auth']['client_token'] # Get AppRole SecretID from Vault var_secret_id = Vault.approle.create_secret_id('app-1').data[:secret_id] ... ``` #### Task 4: Verification Once Terraform completes the `apply` operation, it will output the public IP address of our new server. You can plug that IP address into a browser to see the output. It should look similar to the following: ```plaintext Role ID: f6286b97-246e-9fb4-4d9f-0c9465451851 Secret ID: 72f4b60c-26d0-d947-5026-153943174831 AppRole Token: d11d81e4-0ba1-fefc-03f8-e5f06793b60d Read Our Secrets: {:password=>"$up3r$3cr3t!", :username=>"app-1-user"} ``` ## Additional References The following is a curated list of webinars, blogs and GitHub repositories that add additional context to fill out the concepts discussed in the webinar and demonstrated in the code: - [Managing Secrets in a Container Environment by Jeff Mitchell](https://www.youtube.com/watch?v=skENC9aXgco) - [Using HashiCorp's Vault with Chef written by Seth Vargo](https://www.hashicorp.com/blog/using-hashicorps-vault-with-chef) - [Manage Secrets with Chef and HashiCorps Vault by Seth Vargo & JJ Asghar](https://blog.chef.io/2016/12/12/manage-secrets-with-chef-and-hashicorps-vault/) - [Associated GitHub repository](https://github.com/sethvargo/vault-chef-webinar) - [Vault AppRole Authentication written by Alan Thatcher](http://blog.alanthatcher.io/vault-approle-authentication/) - [Integrating Chef and HashiCorp Vault written by Alan Thatcher](http://blog.alanthatcher.io/integrating-chef-and-hashicorp-vault/) - [Vault Ruby Client](https://github.com/hashicorp/vault-ruby) ## Next Steps Watch the video recording of the [Delivering Secret Zero: Vault AppRole with Terraform and Chef](https://www.hashicorp.com/resources/delivering-secret-zero-vault-approle-terraform-chef) webinar which talks about the usage of AppRole with Terraform and Chef as its trusted entities.