- As I understand it, after deployment, the Agent monitors the deployed files and if any of these files change or disappear on a node, delta is produced. Does the Agent automatically re-run the deployment? Or does it simply notify the console of a mismatch state?
 - As I understand it, after deployment, the Agent monitors the deployed files and if any of these files change or disappear on a node, delta is produced. Does the Agent automatically re-run the deployment?
The agent does not do any monitoring on its own. You can add monitoring to it as described here (http://www.pongasoft.com/blog/yan/glu/2011/03/18/building-monitoring-solution-with-glu/). Each agent stores its state (which script was deployed and in which state of the state machine it's in) in ZooKeeper. It will not monitor (unless you do it manually) that jar_1 has been installed and has not been deleted from a particular location. The console (= webapp) monitors ZooKeeper and knows the state of all agents. There is never an automatic deployment in glu by default. But you can build it on top of it.
 - If one releases a patch consisting of say:
Does the Agent now only monitor this 'new' model? Or does it still produce delta if one or more of the original files changes or disappears?
If you change the model which contains a new script with new value, the console will tell you that there is a delta that needs to be applied.
In the past (many years ago), there was some comparison with Chef and Puppet. At the time they were not playing in the same space at all (they were lower level). As far as I know both those projects are still around and have most likely evolved. Unclear how exactly.
Otherwise it seems that with the latest cloud technologies, Docker, rkt and others, things have changed quite a bit: now you are no longer deploying apps, but entire containers. Although I am not familiar with it at all, Kubernetes is advertising itself as a "production-grade container orchestration".