title: How to check authenticate keycloak instance A user from another keycloak instance B?
body: <p>We setup a testing environment for keycloak. The environment run on GCP. It have two keycloak instances:</p>
  <ol>
  <li>Instance A acts as a test login keycloak, named test-login-1</li>
  <li>Instance B acts as a test external identity provider, named test-login-2</li>
  </ol>
  <p>We need to use the instance A to connect the instance B.</p>
  <p>So instance A user can able to login via instance B.</p>
  <p>Is there any way to do this? How can we implement this logic?</p>