Configuring an LDAP identity provider - Configuring identity providers | Authentication and authorization

Identity providers in OKD
About LDAP authentication
Creating the LDAP secret
Creating a 'configmap'
Sample LDAP custom resource
Adding an identity provider to your cluster

Configure an LDAP identity provider so users can log in to OKD with usernames and passwords validated against your LDAPv3 directory.

Identity providers in OKD

You can configure identity providers by creating a custom resource (CR) that describes the provider and adding it to the cluster. Identity providers enable user authentication in OKD beyond the default kubeadmin user.

OKD usernames containing /, :, and % are not supported.

About LDAP authentication

Review how usernames and passwords are validated against the LDAP directory so you can configure the LDAP identity provider correctly.

During authentication, the LDAP directory is searched for an entry that matches the provided username. If a single unique match is found, a simple bind is attempted using the distinguished name (DN) of the entry plus the provided password.

LDAP authentication uses the following process:

Generates a search filter by combining the attribute and filter in the configured url with the user-provided username.
Searches the directory using the generated filter. Denies access if the search does not return exactly one entry.
Attempts to bind to the LDAP server using the DN of the entry retrieved from the search, and the user-provided password.
Denies access if the bind is unsuccessful.
Builds an identity using the configured attributes as the identity, email address, display name, and preferred username if the bind is successful.

The configured url is an RFC 2255 URL, which specifies the LDAP host and search parameters to use. The syntax of the URL is:

ldap://host:port/basedn?attribute?scope?filter

For this URL:

URL component Description

URL component	Description
`ldap`	For regular LDAP, use the string `ldap`. For secure LDAP (LDAPS), use `ldaps` instead.
`host:port`	The name and port of the LDAP server. Defaults to `localhost:389` for LDAP and `localhost:636` for LDAPS.
`basedn`	The DN of the branch of the directory where all searches should start from. At the very least, this must be the top of your directory tree, but it could also specify a subtree in the directory.
`attribute`	The attribute to search for. Although RFC 2255 allows a comma-separated list of attributes, only the first attribute is used, no matter how many are provided. If no attributes are provided, the default is to use `uid`. It is recommended to choose an attribute that is unique across all entries in the subtree you are using.
`scope`	The scope of the search. Can be either `one` or `sub`. If the scope is not provided, the default is to use a scope of `sub`.
`filter`	A valid LDAP search filter. If not provided, defaults to `(objectClass=*)`

ldap

For regular LDAP, use the string ldap. For secure LDAP (LDAPS), use ldaps instead.

host:port

The name and port of the LDAP server. Defaults to localhost:389 for LDAP and localhost:636 for LDAPS.

basedn

The DN of the branch of the directory where all searches should start from. At the very least, this must be the top of your directory tree, but it could also specify a subtree in the directory.

attribute

The attribute to search for. Although RFC 2255 allows a comma-separated list of attributes, only the first attribute is used, no matter how many are provided. If no attributes are provided, the default is to use uid. It is recommended to choose an attribute that is unique across all entries in the subtree you are using.

scope

The scope of the search. Can be either one or sub. If the scope is not provided, the default is to use a scope of sub.

filter

A valid LDAP search filter. If not provided, defaults to (objectClass=*)

During a search, the attribute and filter from the configured url are combined with the user-provided username to create a search filter in the following format:

(&(<filter>)(<attribute>=<username>))

For example, consider a URL of:

ldap://ldap.example.com/o=Acme?cn?sub?(enabled=true)

When a client attempts to connect using username bob, the resulting search filter is (&(enabled=true)(cn=bob)).

If the LDAP directory requires authentication to search, specify a bindDN and bindPassword to use to perform the entry search.

Creating the LDAP secret

Create a secret that contains the LDAP bind password in the openshift-config namespace so the identity provider can authenticate to the directory.

Procedure

Create a Secret object that contains the bindPassword field by running the following command:
```
$ oc create secret generic ldap-secret --from-literal=bindPassword=<secret> -n openshift-config
```
where:

<secret>

Specifies the LDAP bind password value for the --from-literal argument. The key name must be bindPassword.

Alternatively, apply the following YAML to create the secret:

apiVersion: v1
kind: Secret
metadata:
  name: ldap-secret
  namespace: openshift-config
type: Opaque
data:
  bindPassword: <base64_encoded_bind_password>

Creating a 'configmap'

Create a configmap object in the openshift-config namespace to store the certificate authority bundle that identity providers use to validate secure connections to the remote authentication service.

Procedure

Define an OKD configmap object containing the certificate authority by running the following command:
```
$ oc create configmap ca-config-map --from-file=ca.crt=/path/to/ca -n openshift-config
```

Optional: Apply the following YAML to create the config map:

apiVersion: v1
kind: configmap
metadata:
  name: ca-config-map
  namespace: openshift-config
data:
  ca.crt: |
    <CA_certificate_PEM>

The certificate authority must be stored in the ca.crt key of the configmap object.

Sample LDAP custom resource

Review the sample LDAP custom resource (CR) and acceptable parameter values so you can configure attribute mappings, bind credentials, and connection settings for the LDAP identity provider.

apiVersion: config.openshift.io/v1
kind: OAuth
metadata:
  name: cluster
spec:
  identityProviders:
  - name: ldapidp
    mappingMethod: claim
    type: LDAP
    ldap:
      attributes:
        id:
        - dn
        email:
        - mail
        name:
        - cn
        preferredUsername:
        - uid
      bindDN: ""
      bindPassword:
        name: ldap-secret
      ca:
        name: ca-config-map
      insecure: false
      url: "ldaps://ldaps.example.com/ou=users,dc=acme,dc=com?uid"

where:

spec.identityProviders.name: Specifies the provider name. The provider name is prefixed to the returned user ID to form an identity
spec.identityProviders.mappingMethod: Specifies how mappings are established between the identities of this provider and User objects.
spec.identityProviders.ldap.attributes.id: Specifies the list of attributes to use as the identity. The first non-empty attribute is used. At least one attribute is required. If none of the listed attributes have a value, authentication fails. Defined attributes are retrieved as raw, allowing binary values to be used.
spec.identityProviders.ldap.attributes.email: Specifies the list of attributes to use as the email address. The first non-empty attribute is used.
spec.identityProviders.ldap.attributes.name: Specifies the list of attributes to use as the display name. The first non-empty attribute is used.
spec.identityProviders.ldap.attributes.preferredUsername: Specifies the list of attributes to use as the preferred username when provisioning a user for this identity. The first non-empty attribute is used.
spec.identityProviders.ldap.bindDN: Specifies the optional DN to use to bind during the search phase. Must be set if bindPassword is defined.
spec.identityProviders.ldap.bindPassword: Specifies an optional reference to an OKD Secret object containing the bind password. Must be set if bindDN is defined.
spec.identityProviders.ldap.ca: Specifies an optional reference to an OKD configmap object containing the Privacy-Enhanced Mail (PEM)-encoded certificate authority bundle to use in validating server certificates for the configured URL. Only used when insecure is false.
spec.identityProviders.ldap.insecure: Specifies whether a TLS connection is made to the server. When true, no TLS connection is made to the server. When false, ldaps:// URLs connect using TLS, and ldap:// URLs are upgraded to TLS. This must be set to false when ldaps:// URLs are in use, as these URLs always attempt to connect using TLS.
spec.identityProviders.ldap.url: Specifies an RFC 2255 URL for the LDAP host and search parameters to use.

To allowlist users for an LDAP integration, use the lookup mapping method. Before a login from LDAP is allowed, a cluster administrator must create an Identity object and a User object for each LDAP user.

Additional resources

Identity provider parameters

Adding an identity provider to your cluster

Apply the identity provider custom resource (CR) to your cluster so users can authenticate with the configured identity provider.

Prerequisites

You installed an OKD cluster.
You defined the CR for your identity provider.
You are logged in as an administrator.

Procedure

Apply the defined CR by running the following command:

$ oc apply -f </path/to/CR>

If a CR does not exist, oc apply creates a new CR and might trigger the following warning: Warning: oc apply should be used on resources created by either oc create --save-config or oc apply. In this case you can safely ignore this warning.

Log in to the cluster as a user from your identity provider by running the following command, entering the password when prompted:
```
$ oc login -u <username>
```
Confirm that the user logged in successfully and that the username displays by running the following command:
```
$ oc whoami
```