We're running Ubuntu 14.04 on an EC2 virtual machine. I've been seeing a lot of these errors in our kernel log:
[ 704.032085] xen:balloon: reserve_additional_memory: add_memory() failed: -17
[ 736.096102] xen:balloon: reserve_additional_memory: add_memory() failed: -17
[ 768.160075] xen:balloon: reserve_additional_memory: add_memory() failed: -17
[ 800.224082] xen:balloon: reserve_additional_memory: add_memory() failed: -17
[ 832.288094] xen:balloon: reserve_additional_memory: add_memory() failed: -17
We obviously aren't running Xen within our virtual machine, so these must indicate something to do with the host's allocation of memory. I don't believe it's causing any immediate problems for us, but is it something we should be concerned about?