Error - name resolution is negative (local dtab: Dtab())


#1

Hello,

I’m getting this error in the Linkerd logs, even tough it seems that traffic passes normally.
Does this error indicate a possible issue? or can it be ignored?

I see them also in times when there’s no communication at all (during the night), when I don’t send any requests.

Thanks in advance.


#2

I think we may need to dig into the logs more to determine if it is truly benign. Do you have any captured logs that reveal any additional info around that logged error? Have you tried using the admin UI to see if you are able to still resolve paths?


#3

I’m still able to resolve paths, confirmed in UI.
In the logs I get just a bulk of these messages like so:

I 1219 15:35:54.363 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:35:59.352 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:36:04.362 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:36:09.342 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:36:14.351 UTC THREAD34 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:36:19.363 UTC THREAD34 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:36:24.383 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:36:29.423 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:36:34.443 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:36:39.423 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:36:44.463 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:36:49.483 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:36:54.483 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:36:59.513 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:37:04.492 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:37:09.492 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:37:14.513 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:37:19.484 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:37:24.493 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:37:29.483 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:37:34.523 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:37:39.493 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:37:44.473 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:37:49.433 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:37:54.433 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:37:59.433 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:38:04.463 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:38:09.473 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:38:14.512 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:38:19.533 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:38:24.573 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:38:29.543 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:38:34.542 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())
I 1219 15:38:39.592 UTC THREAD36 TraceId:c9f38f01b46938fe: %/io.l5d.localhost/#/io.l5d.marathon/linkerd-comm/master/serviceb: name resolution is negative (local dtab: Dtab())  

And then nothing, once again, everything seems to work fine.


#4

I think its safe to say that it is in fact harmless but please let us know if you run into issues that stem from this!


#5

Thank you! that’s what I hopped. Hope to not encounter any issues.


#6

Does anyone know any additional details on these types of errors? We are seeing these errors in our environment as well and would like to determine the cause.


#7

“name resolution is negative” indicates that a server name could not be Bound by the Linkerd Resolver. It is unable to get an IP address to establish a connection.