»AppRole Auth Method

The approle auth method allows machines or apps to authenticate with Vault-defined roles. The open design of AppRole enables a varied set of workflows and configurations to handle large numbers of apps. This auth method is oriented to automated workflows (machines and services), and is less useful for human operators.

An "AppRole" represents a set of Vault policies and login constraints that must be met to receive a token with those policies. The scope can be as narrow or broad as desired. An AppRole can be created for a particular machine, or even a particular user on that machine, or a service spread across machines. The credentials required for successful login depend upon the constraints set on the AppRole associated with the credentials.

»Authentication

»Via the CLI

The default path is /approle. If this auth method was enabled at a different path, specify auth/my-path/login instead.

$ vault write auth/approle/login \
    role_id=db02de05-fa39-4855-059b-67221c5c2f63 \
    secret_id=6a174c20-f6de-a53c-74d2-6018fcceff64

Key                Value
---                -----
token              65b74ffd-842c-fd43-1386-f7d7006e520a
token_accessor     3c29bc22-5c72-11a6-f778-2bc8f48cea0e
token_duration     20m0s
token_renewable    true
token_policies     [default]

$ vault write auth/approle/login \    role_id=db02de05-fa39-4855-059b-67221c5c2f63 \    secret_id=6a174c20-f6de-a53c-74d2-6018fcceff64
Key                Value---                -----token              65b74ffd-842c-fd43-1386-f7d7006e520atoken_accessor     3c29bc22-5c72-11a6-f778-2bc8f48cea0etoken_duration     20m0stoken_renewable    truetoken_policies     [default]

»Via the API

The default endpoint is auth/approle/login. If this auth method was enabled at a different path, use that value instead of approle.

$ curl \
    --request POST \
    --data '{"role_id":"988a9df-...","secret_id":"37b74931..."}' \
    http://127.0.0.1:8200/v1/auth/approle/login

$ curl \    --request POST \    --data '{"role_id":"988a9df-...","secret_id":"37b74931..."}' \    http://127.0.0.1:8200/v1/auth/approle/login

The response will contain the token at auth.client_token:

{
  "auth": {
    "renewable": true,
    "lease_duration": 2764800,
    "metadata": {},
    "policies": ["default", "dev-policy", "test-policy"],
    "accessor": "5d7fb475-07cb-4060-c2de-1ca3fcbf0c56",
    "client_token": "98a4c7ab-b1fe-361b-ba0b-e307aacfd587"
  }
}

{  "auth": {    "renewable": true,    "lease_duration": 2764800,    "metadata": {},    "policies": ["default", "dev-policy", "test-policy"],    "accessor": "5d7fb475-07cb-4060-c2de-1ca3fcbf0c56",    "client_token": "98a4c7ab-b1fe-361b-ba0b-e307aacfd587"  }}

Application Integration: See the Code Example section for a code snippet demonstrating the authentication with Vault using the AppRole auth method.

»Configuration

Auth methods must be configured in advance before users or machines can authenticate. These steps are usually completed by an operator or configuration management tool.

»Via the CLI

Enable the AppRole auth method:

$ vault auth enable approle

$ vault auth enable approle

Create a named role:

$ vault write auth/approle/role/my-role \
    secret_id_ttl=10m \
    token_num_uses=10 \
    token_ttl=20m \
    token_max_ttl=30m \
    secret_id_num_uses=40

$ vault write auth/approle/role/my-role \    secret_id_ttl=10m \    token_num_uses=10 \    token_ttl=20m \    token_max_ttl=30m \    secret_id_num_uses=40

Note: If the token issued by your approle needs the ability to create child tokens, you will need to set token_num_uses to 0.

For the complete list of configuration options, please see the API documentation.

Fetch the RoleID of the AppRole:

$ vault read auth/approle/role/my-role/role-id
role_id     db02de05-fa39-4855-059b-67221c5c2f63

$ vault read auth/approle/role/my-role/role-idrole_id     db02de05-fa39-4855-059b-67221c5c2f63

Get a SecretID issued against the AppRole:

$ vault write -f auth/approle/role/my-role/secret-id
secret_id               6a174c20-f6de-a53c-74d2-6018fcceff64
secret_id_accessor      c454f7e5-996e-7230-6074-6ef26b7bcf86
secret_id_ttl           10m

$ vault write -f auth/approle/role/my-role/secret-idsecret_id               6a174c20-f6de-a53c-74d2-6018fcceff64secret_id_accessor      c454f7e5-996e-7230-6074-6ef26b7bcf86secret_id_ttl           10m

»Via the API

Enable the AppRole auth method:

$ curl \
    --header "X-Vault-Token: ..." \
    --request POST \
    --data '{"type": "approle"}' \
    http://127.0.0.1:8200/v1/sys/auth/approle

$ curl \    --header "X-Vault-Token: ..." \    --request POST \    --data '{"type": "approle"}' \    http://127.0.0.1:8200/v1/sys/auth/approle

Create an AppRole with desired set of policies:

$ curl \
    --header "X-Vault-Token: ..." \
    --request POST \
    --data '{"policies": "dev-policy,test-policy"}' \
    http://127.0.0.1:8200/v1/auth/approle/role/my-role

$ curl \    --header "X-Vault-Token: ..." \    --request POST \    --data '{"policies": "dev-policy,test-policy"}' \    http://127.0.0.1:8200/v1/auth/approle/role/my-role

Fetch the identifier of the role:

$ curl \
    --header "X-Vault-Token: ..." \
    http://127.0.0.1:8200/v1/auth/approle/role/my-role/role-id

$ curl \    --header "X-Vault-Token: ..." \    http://127.0.0.1:8200/v1/auth/approle/role/my-role/role-id

The response will look like:

{
  "data": {
    "role_id": "988a9dfd-ea69-4a53-6cb6-9d6b86474bba"
  }
}

{  "data": {    "role_id": "988a9dfd-ea69-4a53-6cb6-9d6b86474bba"  }}

Create a new secret identifier under the role:

$ curl \
    --header "X-Vault-Token: ..." \
    --request POST \
     http://127.0.0.1:8200/v1/auth/approle/role/my-role/secret-id

$ curl \    --header "X-Vault-Token: ..." \    --request POST \     http://127.0.0.1:8200/v1/auth/approle/role/my-role/secret-id

The response will look like:

{
  "data": {
    "secret_id_accessor": "45946873-1d96-a9d4-678c-9229f74386a5",
    "secret_id": "37b74931-c4cd-d49a-9246-ccc62d682a25",
    "secret_id_ttl": 600
  }
}

{  "data": {    "secret_id_accessor": "45946873-1d96-a9d4-678c-9229f74386a5",    "secret_id": "37b74931-c4cd-d49a-9246-ccc62d682a25",    "secret_id_ttl": 600  }}

»Credentials/Constraints

»RoleID

RoleID is an identifier that selects the AppRole against which the other credentials are evaluated. When authenticating against this auth method's login endpoint, the RoleID is a required argument (via role_id) at all times. By default, RoleIDs are unique UUIDs, which allow them to serve as secondary secrets to the other credential information. However, they can be set to particular values to match introspected information by the client (for instance, the client's domain name).

»SecretID

SecretID is a credential that is required by default for any login (via secret_id) and is intended to always be secret. (For advanced usage, requiring a SecretID can be disabled via an AppRole's bind_secret_id parameter, allowing machines with only knowledge of the RoleID, or matching other set constraints, to fetch a token). SecretIDs can be created against an AppRole either via generation of a 128-bit purely random UUID by the role itself (Pull mode) or via specific, custom values (Push mode). Similarly to tokens, SecretIDs have properties like usage-limit, TTLs and expirations.

»Pull And Push SecretID Modes

If the SecretID used for login is fetched from an AppRole, this is operating in Pull mode. If a "custom" SecretID is set against an AppRole by the client, it is referred to as a Push mode. Push mode mimics the behavior of the deprecated App-ID auth method; however, in most cases Pull mode is the better approach. The reason is that Push mode requires some other system to have knowledge of the full set of client credentials (RoleID and SecretID) in order to create the entry, even if these are then distributed via different paths. However, in Pull mode, even though the RoleID must be known in order to distribute it to the client, the SecretID can be kept confidential from all parties except for the final authenticating client by using Response Wrapping.

Push mode is available for App-ID workflow compatibility, which in some specific cases is preferable, but in most cases Pull mode is more secure and should be preferred.

»Further Constraints

role_id is a required credential at the login endpoint. AppRole pointed to by the role_id will have constraints set on it. This dictates other required credentials for login. The bind_secret_id constraint requires secret_id to be presented at the login endpoint. Going forward, this auth method can support more constraint parameters to support varied set of Apps. Some constraints will not require a credential, but still enforce constraints for login. For example, secret_id_bound_cidrs will only allow logins coming from IP addresses belonging to configured CIDR blocks on the AppRole.

»Learn

Refer to the AppRole Pull Authentication guide for a step-by-step tutorial.

»API

The AppRole auth method has a full HTTP API. Please see the AppRole API for more details.

»Code Example

The following code snippet demonstrates AppRole authentication with response wrapping.

AppRole auth with response wrap

package main

import (
    "fmt"
    "io/ioutil"
    "os"
    "strings"

    vault "github.com/hashicorp/vault/api"
)

// Fetches a key-value secret (kv-v2) after authenticating via AppRole,
// an auth method used by machines that are unable to use platform-based authentication mechanisms like AWS Auth, Kubernetes Auth, etc.
func getSecretWithAppRole() (string, error) {
    config := vault.DefaultConfig() // modify for more granular configuration

    client, err := vault.NewClient(config)
    if err != nil {
        return "", fmt.Errorf("unable to initialize Vault client: %w", err)
    }

    // A combination of a Role ID and Secret ID is required to log in to Vault with an AppRole.
    // The Secret ID is a value that needs to be protected, so instead of the app having knowledge of the secret ID directly,
    // we have a trusted orchestrator (https://learn.hashicorp.com/tutorials/vault/secure-introduction?in=vault/app-integration#trusted-orchestrator)
    // give the app access to a short-lived response-wrapping token (https://www.vaultproject.io/docs/concepts/response-wrapping).
    // Read more at: https://learn.hashicorp.com/tutorials/vault/approle-best-practices?in=vault/auth-methods#secretid-delivery-best-practices

    wrappingToken, err := ioutil.ReadFile("path/to/wrapping-token") // placed here by a trusted orchestrator
    if err != nil {
        return "", fmt.Errorf("unable to read file containing wrapping token: %w", err)
    }

    unwrappedToken, err := client.Logical().Unwrap(strings.TrimSuffix(string(wrappingToken), "\n"))
    if err != nil {
        // a good opportunity to alert, in case the one-time use wrapping token appears to have already been used
        return "", fmt.Errorf("unable to unwrap token: %w", err)
    }
    secretID := unwrappedToken.Data["secret_id"]

    // the role ID given to you by your administrator
    roleID := os.Getenv("APPROLE_ROLE_ID")
    if roleID == "" {
        return "", fmt.Errorf("no role ID was provided in APPROLE_ROLE_ID env var")
    }

    params := map[string]interface{}{
        "role_id":   roleID,
        "secret_id": secretID,
    }
    resp, err := client.Logical().Write("auth/approle/login", params)
    if err != nil {
        return "", fmt.Errorf("unable to log in with approle: %w", err)
    }
    client.SetToken(resp.Auth.ClientToken)

    secret, err := client.Logical().Read("kv-v2/data/creds")
    if err != nil {
        return "", fmt.Errorf("unable to read secret: %w", err)
    }

    data, ok := secret.Data["data"].(map[string]interface{})
    if !ok {
        return "", fmt.Errorf("data type assertion failed: %T %#v", secret.Data["data"], secret.Data["data"])
    }

    key := "password"
    value, ok := data[key].(string)
    if !ok {
        return "", fmt.Errorf("value type assertion failed: %T %#v", data[key], data[key])
    }

    return value, nil
}

1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970717273package main
import (    "fmt"    "io/ioutil"    "os"    "strings"
    vault "github.com/hashicorp/vault/api")
// Fetches a key-value secret (kv-v2) after authenticating via AppRole,// an auth method used by machines that are unable to use platform-based authentication mechanisms like AWS Auth, Kubernetes Auth, etc.func getSecretWithAppRole() (string, error) {    config := vault.DefaultConfig() // modify for more granular configuration
    client, err := vault.NewClient(config)    if err != nil {        return "", fmt.Errorf("unable to initialize Vault client: %w", err)    }
    // A combination of a Role ID and Secret ID is required to log in to Vault with an AppRole.    // The Secret ID is a value that needs to be protected, so instead of the app having knowledge of the secret ID directly,    // we have a trusted orchestrator (https://learn.hashicorp.com/tutorials/vault/secure-introduction?in=vault/app-integration#trusted-orchestrator)    // give the app access to a short-lived response-wrapping token (https://www.vaultproject.io/docs/concepts/response-wrapping).    // Read more at: https://learn.hashicorp.com/tutorials/vault/approle-best-practices?in=vault/auth-methods#secretid-delivery-best-practices
    wrappingToken, err := ioutil.ReadFile("path/to/wrapping-token") // placed here by a trusted orchestrator    if err != nil {        return "", fmt.Errorf("unable to read file containing wrapping token: %w", err)    }
    unwrappedToken, err := client.Logical().Unwrap(strings.TrimSuffix(string(wrappingToken), "\n"))    if err != nil {        // a good opportunity to alert, in case the one-time use wrapping token appears to have already been used        return "", fmt.Errorf("unable to unwrap token: %w", err)    }    secretID := unwrappedToken.Data["secret_id"]
    // the role ID given to you by your administrator    roleID := os.Getenv("APPROLE_ROLE_ID")    if roleID == "" {        return "", fmt.Errorf("no role ID was provided in APPROLE_ROLE_ID env var")    }
    params := map[string]interface{}{        "role_id":   roleID,        "secret_id": secretID,    }    resp, err := client.Logical().Write("auth/approle/login", params)    if err != nil {        return "", fmt.Errorf("unable to log in with approle: %w", err)    }    client.SetToken(resp.Auth.ClientToken)
    secret, err := client.Logical().Read("kv-v2/data/creds")    if err != nil {        return "", fmt.Errorf("unable to read secret: %w", err)    }
    data, ok := secret.Data["data"].(map[string]interface{})    if !ok {        return "", fmt.Errorf("data type assertion failed: %T %#v", secret.Data["data"], secret.Data["data"])    }
    key := "password"    value, ok := data[key].(string)    if !ok {        return "", fmt.Errorf("value type assertion failed: %T %#v", data[key], data[key])    }
    return value, nil}