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Configuring a GitLab identity provider

Configure the gitlab identity provider so users can log in to OpenShift Container Platform with GitLab account credentials through OAuth.

Identity providers in OpenShift Container Platform​

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 OpenShift Container Platform beyond the default kubeadmin user.

note

OpenShift Container Platform usernames containing /, :, and % are not supported.

About GitLab authentication​

Review GitLab authentication options for OpenShift Container Platform. Use this integration when you want users to log in with GitLab account credentials through OAuth or OpenID Connect.

If you use GitLab version 7.7.0 to 11.0, you connect using OAuth integration. If you use GitLab version 11.1 or later, you can use OpenID Connect (OIDC) to connect instead of OAuth.

Additional resources

Create the secret​

Create a Secret object in the openshift-config namespace to store the client secret for your identity provider. The identity provider custom resource (CR) references this secret during configuration.

Procedure

  1. Create a Secret object containing the client secret by running the following command: 
    $ oc create secret generic <secret_name> --from-literal=clientSecret=<secret> -n openshift-config
  2. Optional: Apply the following YAML to create the secret: 
    apiVersion: v1
    kind: Secret
    metadata:
      name: <secret_name>
      namespace: openshift-config
    type: Opaque
    data:
      clientSecret: <base64_encoded_client_secret>
  3. Create a Secret object from a file by running the following command: 
    $ oc create secret generic <secret_name> --from-file=<path_to_file> -n openshift-config

Create a ConfigMap​

Create a ConfigMap object in the openshift-config namespace that contains the certificate authority bundle for the identity provider. OpenShift Container Platform uses this bundle to validate Transport Layer Security (TLS) connections to the identity provider.

Procedure

  1. Define an OpenShift Container Platform ConfigMap object containing the CA by running the following command:

    $ oc create configmap ca-config-map --from-file=ca.crt=/path/to/ca -n openshift-config

  2. 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 CA must be stored in the ca.crt key of the ConfigMap object.

Sample GitLab custom resource​

Review the sample GitLab OAuth custom resource (CR) to understand provider parameters and acceptable values before you configure the identity provider in your cluster.

apiVersion: config.openshift.io/v1
kind: OAuth
metadata:
  name: cluster
spec:
  identityProviders:
  - name: gitlabidp
    mappingMethod: claim
    type: GitLab
    gitlab:
      clientID: {...}
      clientSecret:
        name: gitlab-secret
      url: https://gitlab.com
      ca:
        name: ca-config-map

where:

spec.identityProviders.name
Specifies that the provider name is prefixed to the GitLab numeric user ID to form an identity name. It is also used to build the callback URL.
spec.identityProviders.mappingMethod
Specifies how mappings are established between identities from this provider and User objects.
spec.identityProviders.gitlab.clientID
Specifies the client ID of a registered GitLab OAuth application. The application must be configured with a callback URL of https://oauth-openshift.apps.<cluster-name>.<cluster-domain>/oauth2callback/<idp-provider-name>.
spec.identityProviders.gitlab.clientSecret
Specifies a reference to an OpenShift Container Platform Secret object containing the client secret issued by GitLab.
spec.identityProviders.gitlab.url
Specifies the host URL of a GitLab provider. This could either be https://gitlab.com/ or any other self-hosted instance of GitLab.
spec.identityProviders.gitlab.ca
Specifies a reference to an OpenShift Container Platform ConfigMap object containing the PEM-encoded certificate authority bundle to use in validating server certificates for the configured URL. This value is optional.

Additional resources

Add an identity provider to your cluster​

Apply the identity provider custom resource (CR) to your cluster after you define it. With this configuration, you can authenticate with the configured identity provider.

Prerequisites

  • You have access to a OpenShift Container Platform cluster.
  • You have created the CR for your identity providers.
  • You are logged in as an administrator.

Procedure

  1. Apply the defined CR by running the following command:

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

    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.

  2. Log in to the cluster as a user from your identity provider, entering the password when prompted.

    $ oc login -u <username>

  3. Confirm that the user logged in successfully and that the username displays by running the following command:

    $ oc whoami

Additional resources