Configuring a GitHub or GitHub Enterprise identity provider

You can use the GitHub integration to connect to either GitHub or GitHub Enterprise. For GitHub Enterprise integrations, you must provide the hostname of your instance and can optionally provide a ca certificate bundle to use in requests to the server.

Configuring GitHub authentication allows users to log in to OKD with their GitHub credentials. To prevent anyone with any GitHub user ID from logging in to your OKD cluster, you can restrict access to only those in specific GitHub organizations.

By default, only a kubeadmin user exists on your cluster. To specify an identity provider, you must create a custom resource (CR) that describes that identity provider and add it to the cluster.

OKD user names containing /, :, and % are not supported.

Registering a GitHub application

To use GitHub or GitHub Enterprise as an identity provider, you must register an application to use.

Procedure

Register an application on GitHub:
- For GitHub, click → Developer settings → → Register a new OAuth application.
- For GitHub Enterprise, go to your GitHub Enterprise home page and then click Settings → Developer settings → Register a new application.
Enter an application name, for example My OpenShift Install.
Enter a homepage URL, such as https://oauth-openshift.apps.<cluster-name>.<cluster-domain>.
Optional: Enter an application description.

For example:

https://oauth-openshift.apps.example-openshift-cluster.com/oauth2callback/github/

Click Register application. GitHub provides a client ID and a client secret. You need these values to complete the identity provider configuration.

Identity providers use OKD Secret objects in the openshift-config namespace to contain the client secret, client certificates, and keys.

You can define an OKD Secret object containing a string by using the following command.
You can define an OKD Secret object containing the contents of a file, such as a certificate file, by using the following command.

Creating a config map

Identity providers use OKD ConfigMap objects in the openshift-config namespace to contain the certificate authority bundle. These are primarily used to contain certificate bundles needed by the identity provider.

Procedure

Define an OKD ConfigMap object containing the certificate authority by using the following command. The certificate authority must be stored in the ca.crt key of the ConfigMap object.
```
$ oc create configmap ca-config-map --from-file=ca.crt=/path/to/ca -n openshift-config
```

The following custom resource (CR) shows the parameters and acceptable values for a GitHub identity provider.

GitHub CR

apiVersion: config.openshift.io/v1
kind: OAuth
metadata:
spec:
  identityProviders:
  - name: githubidp (1)
    mappingMethod: claim (2)
    type: GitHub
    github:
      ca: (3)
        name: ca-config-map
      clientID: {...} (4)
        name: github-secret
      hostname: ... (6)
      organizations: (7)
      - myorganization1
      - myorganization2
      teams: (8)
      - myorganization1/team-a
      - myorganization2/team-b

1	This provider name is prefixed to the GitHub numeric user ID to form an identity name. It is also used to build the callback URL.
2	Controls how mappings are established between this provider’s identities and `User` objects.
3	Optional: Reference to an OKD `ConfigMap` object containing the PEM-encoded certificate authority bundle to use in validating server certificates for the configured URL. Only for use in GitHub Enterprise with a non-publicly trusted root certificate.
4	The client ID of a registered GitHub OAuth application. The application must be configured with a callback URL of `;`.
5	Reference to an OKD `Secret` object containing the client secret issued by GitHub.
6	For GitHub Enterprise, you must provide the hostname of your instance, such as `example.com`. This value must match the GitHub Enterprise `hostname` value in in the file and cannot include a port number. If this value is not set, then either `teams` or `organizations` must be defined. For GitHub, omit this parameter.
7	The list of organizations. Either the `organizations` or `teams` field must be set unless the `hostname` field is set, or if `mappingMethod` is set to `lookup`. Cannot be used in combination with the `teams` field.
8	The list of teams. Either the `teams` or `organizations` field must be set unless the `hostname` field is set, or if `mappingMethod` is set to `lookup`. Cannot be used in combination with the `organizations` field.

Additional resources

See Identity provider parameters for information on parameters, such as mappingMethod, that are common to all identity providers.

Adding an identity provider to your clusters

Prerequisites

Create an OKD cluster.
Create the custom resource (CR) for your identity providers.
You must be logged in as an administrator.

Procedure

Apply the defined 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.

Obtain a token from the OAuth server.

As long as the kubeadmin user has been removed, the oc login command provides instructions on how to access a web page where you can retrieve the token.

You can also access this page from the web console by navigating to (?) Help → Command Line Tools → Copy Login Command.
Log in to the cluster, passing in the token to authenticate.
```
$ oc login --token=<token>
```