Architecture help for a basic requirement

I want to run a specific cookbook (or command) after every approval (I am think of working around this by increasing the version of chef book).

I also need to run this cookbook as soon as the node is online if the node was offline when I did `knife l .(is this the default way the chef server works ?) can someone suggest me if it is the right way to do ? or if there is a better way of doing it ?

I just explored the basics of chef!