- lista node action e' la lista che contiene i nodi su i quali intervenire

per tutti i processati con successo Processed =1

1) controllo se c'e' un primary cluster
2) per ogni nodo in nodelist  controllo
	wsrep status <> 4 
		se donor or joiner 
	desync 
	reject queries
	pxc_maint
	readonly
	
3) controllo pxc view
	se manca aggiungo alla lista di node-action
	
4) controllo se c'e un host in write.
	se manca in base al weight prendo un nodo da backup e faccio il match con la lista dei nodi buoni (non in lista action come demote)


quindi in short ...
    definisco se sono in primary
    vedo tutti nodi -> read prima -> write dopo
    se write non ha writers allora prendo un read e lo metto
    se read non ha reders e writerIsAlsoReader <> 1 metto il writer in read




Move to offline_soft  if:
	wsrep <> 4 and lenght > 1
	desync
	pxc_maint
move to other hg if:
	Node/cluster in non primary
    wsrep_reject_queries different from NONE
    Donor, node reject queries =1 size of cluster
    
remove from writer hg if read_only > 1


logica failover
	writer is missed length = 0 , first in the backup writer list by weight
	
logica failback
	on promote of a node if in the node is in backup writer and weight > current writer
		node promoting add to writer list
		old writer goes to offline_soft and is flagged for removal (comment REMOVE_OLD_WRITER|Connections_#number)
		
logica remove nodes from OFFLINE_soft
	any node in writer hg offline_soft con connections = 0 viene rimosso

logica promote from offline soft
	any node in reader hg that:
		1) Node state is 4
		2) pxc_maint disable
       	3) wsrep_reject_queries = none
       	4) Primary state
       	
logica promote from HG maint
		1) Node state is 4
		2) pxc_maint disable
       	3) wsrep_reject_queries = none
       	4) Primary state
