140 lines
6.4 KiB
Plaintext
140 lines
6.4 KiB
Plaintext
---
|
|
layout: docs
|
|
page_title: ACL Auth Methods
|
|
sidebar_title: Auth Methods
|
|
description: >-
|
|
An auth method is a component in Consul that performs authentication against a
|
|
trusted external party to authorize the creation of an ACL tokens usable
|
|
within the local datacenter.
|
|
---
|
|
|
|
# ACL Auth Methods
|
|
|
|
-> **1.5.0+:** Auth methods only exist in Consul versions 1.5.0 and newer.
|
|
|
|
An auth method is a component in Consul that performs authentication against a
|
|
trusted external party to authorize the creation of an ACL tokens usable within
|
|
the local datacenter.
|
|
|
|
## Overview
|
|
|
|
Without an auth method a trusted operator is critically involved in the
|
|
creation and secure introduction of each ACL token to every application that
|
|
needs one, while ensuring that the policies assigned to these tokens follow the
|
|
principle of least-privilege.
|
|
|
|
When running in environments such as a public cloud or when supervised by a
|
|
cluster scheduler, applications may already have access to uniquely identifying
|
|
credentials that were delivered securely by the platform. Consul auth method
|
|
integrations allow for these credentials to be used to create ACL tokens with
|
|
properly-scoped policies without additional operator intervention.
|
|
|
|
In Consul 1.5.0 the focus is around simplifying the creation of tokens with the
|
|
privileges necessary to participate in a [Connect](/docs/connect)
|
|
service mesh with minimal operator intervention.
|
|
|
|
## Supported Types
|
|
|
|
| Types | Consul Version |
|
|
| ------------------------------------------------- | --------------------------------- |
|
|
| [`kubernetes`](/docs/acl/auth-methods/kubernetes) | 1.5.0+ |
|
|
| [`jwt`](/docs/acl/auth-methods/jwt) | 1.8.0+ |
|
|
| [`oidc`](/docs/acl/auth-methods/oidc) | 1.8.0+ <EnterpriseAlert inline /> |
|
|
|
|
## Operator Configuration
|
|
|
|
An operator needs to configure each auth method that is to be trusted by
|
|
using the API or command line before they can be used by applications.
|
|
|
|
- **Authentication** - One or more **auth methods** should be configured with
|
|
details about how to authenticate application credentials. Successful
|
|
validation of application credentials will return a set of trusted identity
|
|
attributes (such as a username). These can be managed with the `consul acl auth-method` subcommands or the corresponding [API
|
|
endpoints](/api/acl/auth-methods). The specific details of
|
|
configuration are type dependent and described in their own documentation
|
|
pages.
|
|
|
|
- **Authorization** - One or more **binding rules** must be configured to define
|
|
how to translate trusted identity attributes from each auth method into
|
|
privileges assigned to the ACL token that is created. These can be managed
|
|
with the `consul acl binding-rule` subcommands or the corresponding [API
|
|
endpoints](/api/acl/binding-rules).
|
|
|
|
-> **Note** - To configure auth methods in any connected secondary datacenter,
|
|
[ACL token replication](/docs/agent/options#acl_enable_token_replication)
|
|
must be enabled. Auth methods require the ability to create local tokens which
|
|
is restricted to the primary datacenter and any secondary datacenters with ACL
|
|
token replication enabled.
|
|
|
|
## Binding Rules
|
|
|
|
Binding rules allow an operator to express a systematic way of automatically
|
|
linking [roles](/docs/acl/acl-system#acl-roles) and [service
|
|
identities](/docs/acl/acl-system#acl-service-identities) to newly created
|
|
tokens without operator intervention.
|
|
|
|
Successful authentication with an auth method returns a set of trusted
|
|
identity attributes corresponding to the authenticated identity. Those
|
|
attributes are matched against all configured binding rules for that auth
|
|
method to determine what privileges to grant the the Consul ACL token it will
|
|
ultimately create.
|
|
|
|
Each binding rule is composed of two portions:
|
|
|
|
- **Selector** - A logical query that must match the trusted identity
|
|
attributes for the binding rule to be applicable to a given login attempt.
|
|
The syntax uses github.com/hashicorp/go-bexpr which is shared with the [API
|
|
filtering feature](/api/features/filtering). For example:
|
|
`"serviceaccount.namespace==default and serviceaccount.name!=vault"`
|
|
|
|
- **Bind Type and Name** - A binding rule can bind a token to a
|
|
[role](/docs/acl/acl-system#acl-roles) or to a [service
|
|
identity](/docs/acl/acl-system#acl-service-identities) by name. The name
|
|
can be specified with a plain string or the bind name can be lightly
|
|
templated using [HIL syntax](https://github.com/hashicorp/hil) to interpolate
|
|
the same values that are usable by the `Selector` syntax. For example:
|
|
`"dev-${serviceaccount.name}"`
|
|
|
|
When multiple binding rules match, then all roles and service identities are
|
|
jointly linked to the token created by the login process.
|
|
|
|
## Overall Login Process
|
|
|
|
Applications are responsible for exchanging their auth method specific secret
|
|
bearer token for a Consul ACL token by using the login process:
|
|
|
|
![diagram of auth method login](/img/auth-methods.svg)
|
|
|
|
1. Applications use the `consul login` subcommand or the [login API
|
|
endpoint](/api/acl/acl#login-to-auth-method) to authenticate to a
|
|
specific auth method using their local Consul client. Applications provide
|
|
both the name of the auth method and a secret bearer token during login.
|
|
|
|
2. The Consul client forwards login requests to the leading Consul server.
|
|
|
|
3. The Consul leader then uses auth method specific mechanisms to validate the
|
|
provided bearer token credentials.
|
|
|
|
4. Successful validation returns trusted identity attributes to the Consul
|
|
leader.
|
|
|
|
5. The Consul leader consults the configured set of binding rules associated
|
|
with the specified auth method and selects only those rules that match the
|
|
trusted identity attributes.
|
|
|
|
6. The Consul leader uses the matching binding rules to generate a list of
|
|
roles and service identities and assigns them to a token created exclusively
|
|
in the _local_ datacenter. If none are generated the login attempt fails.
|
|
|
|
7. The relevant `SecretID` and remaining details about the token are returned to
|
|
the originating Consul client.
|
|
|
|
8. The Consul client returns the token details back to the application.
|
|
|
|
9. (later) Applications SHOULD use the `consul logout` subcommand or the
|
|
[logout API endpoint](/api/acl/acl#logout-from-auth-method) to destroy
|
|
their token when it is no longer required.
|
|
|
|
For more details about specific auth methods and how to configure them, click
|
|
on the name of the auth method type in the sidebar.
|