There are plenty of network monitoring tools you could use...
Here is TSQL I use to see what node is running. The first line of 'net statistics server' returns the node name. I then compare to what it should be, or to see if there is a change. When a change occurs, you could send email etc.
create
table #Output(rowid int identity (1,1),x varchar(8000))
insert
#Output exec xp_cmdshell 'net statistics server'
select
top 1 x from #Output order by rowid
drop
table #Output
Terry