I just upgraded my test cluster from 5.1.2 to 5.2 and i can see a "new warning" in my logs, i think is from Netty (which was upgraded from 4.1.6 to 4.1.7 according to docs)
[2017-02-02T14:46:48,481][WARN ][i.n.u.i.MacAddressUtil ] Failed to find a usable hardware address from the network interfaces; using random bytes: 85:6d:c7:97:c3:fa:6d:3b
This will repeat every time i start elasticsearch selecting a different random address.
Of course i do have a valid mac address
# ifconfig eth0 | egrep ^eth0 eth0 Link encap:Ethernet HWaddr 52:54:00:F9:32:BD
The only reference i was able to find to this issue is for Netty 4.1.0 beta , and it should be fixed in 4.1.7
Everything seems to be working fine though. not only my cluster looks good but tcpdump show the correct mac address , the interface one rather than the random one, for port 9300.
Before i consider to upgrade my live clusters though i need to understand if this is an issue in any way and what is causing it.
Does anyone know what this is ?
Is it new in 5.2.0 or did i simply miss it / not log it before ?