public void addMockServers(List<? extends DataNodeId> newNodes, ClusterMap clusterMap) {
    newNodes.forEach(node -> mockServers.putIfAbsent(node,
        new MockServer(clusterMap, node.getDatacenterName(), node.getHostname(), node.getHttp2Port(), this)));
  }
Dynamically add new mock servers into layout.
@param newNodes a list of new nodes to add.
@param clusterMap the {@link ClusterMap} used to associate a host and port with a MockServer.
ambry-router/src/test/java/com/github/ambry/router/MockServerLayout.java