moveRootTabletToRootTable(zoo);
// add system namespace permissions to existing users
ZKPermHandler perm = new ZKPermHandler();
perm.initialize(instance.getInstanceID(), true);
String users = ZooUtil.getRoot(instance) + "/users";
for (String user : zoo.getChildren(users)) {
zoo.putPersistentData(users + "/" + user + "/Namespaces", new byte[0], NodeExistsPolicy.SKIP);
perm.grantNamespacePermission(user, Namespaces.ACCUMULO_NAMESPACE_ID, NamespacePermission.READ);
}