All changes on cookbook could not upload to chef server

Chef Infra (archive)
1

Hi, All

I am a newbie on chef, I got blocked on cookbook, please help me with this, thanks in advance.

I create a new cookbook and modify default.rb, add followings
package “vsftpd” do
action :install
end
Then I upload it to chef server
knife cookbook upload cookbook01
But, I find all changes are lost on chef-server
knife cookbook show cookbook01 0.1.0 recipes default.rb
#
# Cookbook Name:: cookbook01
# Recipe:: default
#
# Copyright 2017, YOUR_COMPANY_NAME
#
# All rights reserved - Do Not Redistribute
#

Am I missing something?

My ENV:
chef-server-core-12.15.6-1
chef-manage-2.5.3-1
chefdk-1.3.43-1
chef-13.0.118-1

Chef server and Chef workstation are on the same machine.

Thanks.