static AccessControlList buildAdminAcl(Configuration conf) {
    // Initialize admin users based on whether http ui auth is set to ldap or kerberos
    String httpAuthType = conf.get(HttpServer.HTTP_UI_AUTHENTICATION, "").toLowerCase();
    final String adminUsers = getAdminUsers(conf, httpAuthType);
    final String adminGroups =
      conf.get(HttpServer.HTTP_SPNEGO_AUTHENTICATION_ADMIN_GROUPS_KEY, null);
    if (adminUsers == null && adminGroups == null) {
      // Backwards compatibility - if the user doesn't have anything set, allow all users in.
      return new AccessControlList("*", null);
    }
    return new AccessControlList(adminUsers, adminGroups);
  }
Builds an ACL that will restrict the users who can issue commands to endpoints on the UI which
are meant only for administrators.
hbase-http/src/main/java/org/apache/hadoop/hbase/http/InfoServer.java