API impersonation

A request to the OpenShift Container Platform API can include an Impersonate-User header, which indicates that the requester wants the request handled as though it came from the specified user.

Before User A can impersonate User B, User A is authenticated. Then, an authorization check occurs to ensure that User A is allowed to impersonate the user named User B. If User A is requesting to impersonate a service account, system:serviceaccount:namespace:name, OpenShift Container Platform confirms that User A can impersonate the serviceaccount named name in namespace. If the check fails, the request fails with a 403 (Forbidden) error code.

By default, project administrators and editors can impersonate service accounts in their namespace. The sudoers role allows a user to impersonate system:admin, which in turn has cluster administrator permissions. The ability to impersonate system:admin grants some protection against typos, but not security, for someone administering the cluster. For example, running oc delete nodes --all fails, but running oc delete nodes --all --as=system:admin succeeds.

Impersonating the system:admin user

You can grant a user permission to impersonate system:admin, which grants them cluster administrator permissions.

  • To grant a user permission to impersonate system:admin, run the following command:

    $ oc create clusterrolebinding <any_valid_name> --clusterrole=sudoer --user=<username>