resolv.conf no such file o directory

[danisilver]

i just left to install docker on ubuntu 12.04 from this guide :
http://docs.docker.io/en/latest/installation/ubuntulinux/
and i got this

➜ ~ sudo docker run -i -t ubuntu /bin/bash
2014/03/26 11:45:17 Error: open /etc/resolv.conf: no such file or directory

any suggestions?

[lafolle]

Problem with your host machine. Create /etc/resolv.conf and populate it with appropriate DNS information and try the command again.

[unclejack]

This isn't a Docker bug, it's a problem caused by the absence of /etc/resolv.conf on your host. I can reproduce the problem when there's no resolv.conf on the host.

Please fix your Linux system.

[ghost]

IMHO the file is not necessary, is it? So, it shouldn't be about a broken OS.
http://man7.org/linux/man-pages/man5/resolv.conf.5.html

[lafolle]

If this file does not exist, only the name server on the local machine will be queried;

In that case DNS server should be running on your local machine.

[OOPMan]

I experience this issue and it seems to be a side-effect of the NetworkManager config on my distribution, Sabayon Linux.

In my case, /etc/resolv.conf is a symlink to /etc/resolvconf/run/resolve.conf and is only created after NetworkManager connects to a network. This makes Docker fail to start on boot but it starts fine after I've logged in and connect to a network.

[crosbymichael]

@OOPMan In your init script shouldn't you depend on NetworkManager being up before the docker service is started?

[tianon]

I also wonder if this should be an upstream Go (specifically "netgo") issue - do we actually check for resolv.conf directly, or only indirectly via the netgo implementation?

[OOPMan]

I've realised that my problem has nothing to do with NM or Sabayon Linux :-)

I am running on an Asus X550CC. Overall, a decent machine but it has one caveat: The Wi-Fi hardware is disabled under Linux until you sleep and then resume. This means that on boot, unconnected to a wired LAN, the system basically decides there is no working network and hence /etc/resolv.conf doesn't contain anything. Docker doesn't like this and hence fails to start.

Once I've suspend-resumed then everything is fine and Docker starts.

[duffsterlp]

@unclejack @crosbymichael I am still seeing this issue today on docker version 1.12.6.
Why does /etc/resolv.conf gate running docker containers?

[runcom]

I think there hasn't been a good answer on this and since I'm also experiencing this I'm reopening. @thaJeztah could you ping network maintainers? At this point I don't understand why container start is gated by network (we do have isolated machines where there's no resolv.conf file but we want to start containers anyway)

[stefwalter]

The resolv.conf manual (from glibc) states:

   If this file does not exist, only the name server on the local
   machine will be queried; the domain name is determined from the
   hostname and the domain search path is constructed from the domain
   name.

Therefore it should be assumed that a Linux system without a resolv.conf is a valid Linux system.

Other software such as golang's DNS resolv.conf loading logic, deals with missing or inaccessible resolv.conf in the same way: https://golang.org/src/net/dnsconfig_unix.go

[martinpitt]

Also, resolv.conf is not necessary on systems which use non-libc NSS modules such as nss-resolve or winbind, ldap, etc.

[thaJeztah]

/cc @sanimej

[saimonn]

This bug also prevent from using docker offline on some distributions.

[hqhq]

Trying to fix it in: moby/libnetwork#1847

[HeGuanyuan]

just create an empty file names 'resolv.conf' at the place, my problem solved~

[thaJeztah]

I see the fix for this was merged through 1ddeb11, which will be included in the upcoming 17.10 release; https://github.com/docker/docker-ce/blob/17.10/components/engine/vendor/github.com/docker/libnetwork/sandbox_dns_unix.go

closing, because this is resolved on master 👍