[Hawkular-dev] RfC: Remove / rename servers from / in inventory

[Heiko W.Rupp]

Hey,

currently we can add (WF) servers to inventory easily, but we can't get 
rid of them anymore. Similarly it is not really clear what should happen 
if a serve changes its name.

In WildFly 10 supposedly a new uuid kind of thing should appear, that 
would identify each WF uniquely and which could serve as the "primary 
key", so that the name is just a display attribute that can be changed 
at will, so that the renaming piece is sort of solved.

Now to the semantics of "uninventory" (not deletion of physical 
servers).
In RHQ we had uninventory that removed the server from inventory.
After a discovery scan happened, it showed up again and could be 
re-inventoried.
During uninventory, all collected metrics etc. and alert definitions for 
the resource
were wiped (or prepared for wiping).
This (wiping of recorded metrics) has more than one time been mentioned 
as undesired e.g. in case that the uninventory happened due to bad luck. 
Also in RHQ there were issues when e.g. the machine where a WF-server 
was running on got renamed.

Some questions that come to mind:
- Should we wipe data when a server gets uninventoried?
- How can we prevent it from entering inventory directly after an 
uninventory again?
- what states do we need (data wiping may take too long to be done 
synchronously)?
- would users perhaps want a data dump to external storage before 
wiping?
- How can we make sure that servers without that uuid can still be 
identified even after rename (of the machine)?
- How can we make sure that servers without that uuid can still be 
identified even when they are moved to a different pod

   Heiko