Slow IP resolution of docker container

Docker Desktop
1

I see very long delays in resolving the IP of the container, is this expected?

$ time curl -o - http://192.168.64.2 > /dev/null
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   612  100   612    0     0   542k      0 --:--:-- --:--:-- --:--:--  597k

real	0m0.017s
user	0m0.004s
sys	0m0.006s
$ time curl -o - http://docker.local > /dev/null
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   612  100   612    0     0    110      0  0:00:05  0:00:05 --:--:--   152

real	0m5.561s
user	0m0.004s
sys	0m0.008s

$ pinata diagnose -u
OS X: version 10.11.4 (build: 15E65)
Docker.app: version v1.10.3-beta5
Running diagnostic tests:
[OK]      docker-cli
[OK]      Moby booted
[OK]      driver.amd64-linux
[OK]      vmnetd
[OK]      lofs
[OK]      osxfs
[OK]      db
[OK]      slirp
[OK]      menubar
[OK]      environment
[OK]      Docker
[OK]      VT-x
Docker logs are being collected into /tmp/20160331-225433.tar.gz.
Your unique id in bugsnag is: A5C65C17-C407-462C-AB01-8DECCFB46F44
1 Like
2

Unfortunately yes this is outside our control, there seems to be a timeout of normal DNS before .local is tried. We may be going to switch away from using .local which would resolve this.

2 Likes
3

I’d like to vote for this issue as well. It makes docker.local pretty useless if it is so slow. We’ve had to resolve the ip on our own to account for this issue during the beta

4

to me this is a non starter. There is another thread for figuring out the IP by doing some greps and running an alpine container. It seems crazy that you have to jump through that many hoops just to be abel to get the IP in order to curl the box. Before I was able to run docker-machine ip default.

2 Likes
5

Thankfully this seems to only (mostly?) affect shell commands, at least on my machine browsers happily resolve docker.local without delay.

6

Same issue here - some commands seem to resolve the name very quickly, others take up to 10s.

With Docker Machine at least you could check for $DOCKER_HOST to find the IP, or assume localhost. Docker for Mac seems to be a step in the right direction with docker.local but resolution time of 10s makes it kind of useless for many applications.

7

I read that docker.local is now deprecated and VPN support and localhost
are now the default.

8

yeah all good now with latest upgrade :wink:

9

I’m still seeing slow (approx 1s) resolutions having moved to beta 9 and using localhost