Docker cannot access .local domains - docker

Question

I am trying to access devices on my network with .local domain, but it doesn't seem to work in Docker.
Ping from host is working:
$ ping test1.local
PING test1.local (192.168.1.90) 56(84) bytes of data.
64 bytes from 192.168.1.90 (192.168.1.90): icmp_seq=1 ttl=255 time=1.41 ms
64 bytes from 192.168.1.90 (192.168.1.90): icmp_seq=2 ttl=255 time=1.54 ms
Docker demon config:
$ cat /etc/docker/daemon.json
{
"dns": ["192.168.1.1","8.8.8.8"]
}
If I try to ping test1.local from Docker:
$ sudo docker run --network host busybox ping -c 3 test1.local
ping: bad address 'test1.local'
Pinging device with IP works:
$ sudo docker run --network host busybox ping -c 3 192.168.1.90
PING 192.168.1.90 (192.168.1.90): 56 data bytes
64 bytes from 192.168.1.90: seq=0 ttl=255 time=4.855 ms
64 bytes from 192.168.1.90: seq=1 ttl=255 time=1.566 ms
So I assume something is wrong name resolution.
madrian#ubuntudev:~$ cat /etc/resolv.conf
$ cat /etc/resolv.conf
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
# DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
# 127.0.0.53 is the systemd-resolved stub resolver.
# run "systemd-resolve --status" to see details about the actual nameservers.
nameserver 127.0.0.1
search localdomain
Any ideas how to resolve this issue?

Answer 1

Try run your code without --network host argument. The problem is in the DNS resolution.
When you use default bridge (which will be used if you omit network parameter), containers inherit DNS configuration from host, and that is what you need:
https://docs.docker.com/v17.09/engine/userguide/networking/default_network/configure-dns/
When you use user-defined bridge, Docker updates DNS records to enable seamless communication between containers by their names:
https://docs.docker.com/v17.09/engine/userguide/networking/configure-dns/
Unfortunately, I was unable to find explicit explanation on how DNS works with host mode, so I assume this is a problem