azure docker dns windows-server-2019 docker-ee

Docker build cannot resolve DNS on Windows Server 2019

Problem

Running the following command:

docker build  --rm -f "c:\Users\...\iotedgeModbus\Dockerfile.amd64.debug" -t
modbus:dev-amd64.debug "c:\Users\...\iotedgeModbus" ; if ($?) { iotedgehubdev start -d "c:\Users\...\iotedgeModbus\config\deployment.debug.amd64.json" -v }

outputs errors related to resolving DNS names:

Step 2/21 : RUN apt-get update &&     apt-get install -y --no-install-recommends unzip procps
&&     rm -rf /var/lib/apt/lists/*
 ---> Running in a389a7d1ff0d
Err:1 http://security.debian.org/debian-security buster/updates InRelease
  Temporary failure resolving 'security.debian.org'
Err:2 http://deb.debian.org/debian buster InRelease
  Temporary failure resolving 'deb.debian.org'
Err:3 http://deb.debian.org/debian buster-updates InRelease
  Temporary failure resolving 'deb.debian.org'
Reading package lists...

Full stack trace:

docker build  --rm -f "c:\Users\...\iotedgeModbus\Dockerfile.amd64.debug" -t
modbus:dev-amd64.debug "c:\Users\...\iotedgeModbus" ; if ($?) { iotedgehubdev start -d "c:\Users\...\iotedgeModbus\config\deployment.debug.amd64.json" -v }
Sending build context to Docker daemon  699.9kB
Step 1/21 : FROM mcr.microsoft.com/dotnet/core/runtime:3.0.0-buster-slim AS base
 ---> b525e32f0752
Step 2/21 : RUN apt-get update &&     apt-get install -y --no-install-recommends unzip procps
&&     rm -rf /var/lib/apt/lists/*
 ---> Running in a389a7d1ff0d
Err:1 http://security.debian.org/debian-security buster/updates InRelease
  Temporary failure resolving 'security.debian.org'
Err:2 http://deb.debian.org/debian buster InRelease
  Temporary failure resolving 'deb.debian.org'
Err:3 http://deb.debian.org/debian buster-updates InRelease
  Temporary failure resolving 'deb.debian.org'
Reading package lists...
W: Failed to fetch http://deb.debian.org/debian/dists/buster/InRelease  Temporary failure resolving 'deb.debian.org'
W: Failed to fetch http://security.debian.org/debian-security/dists/buster/updates/InRelease
Temporary failure resolving 'security.debian.org'
W: Failed to fetch http://deb.debian.org/debian/dists/buster-updates/InRelease  Temporary failure resolving 'deb.debian.org'
W: Some index files failed to download. They have been ignored, or old ones used instead.
Reading package lists...
Building dependency tree...
Reading state information...
E: Unable to locate package unzip
E: Unable to locate package procps
The command '/bin/sh -c apt-get update &&     apt-get install -y --no-install-recommends unzip procps &&     rm -rf /var/lib/apt/lists/*' returned a non-zero code: 100

Setup

I have the following configuration:

Azure VM (Standard D2s v3 [2 vcpus, 8 GiB memory])
VM OS is Windows Server 2019 Datacenter v1809
Docker EE (v19.03.04 for both Server and Client engines)
WSL installed and tested via this guide.
LCOW enabled, tested, and set as the default via this guide
daemon.json file configured with DNS servers
Host is connected to the internet

Background

I am trying to debug an issue that my container is experiencing in the production environment, so I want to run it on the production machine.

Docker configuration

Contents of daemon.json file:

{
    "experimental": true,
    "dns": ["208.67.222.222", "208.67.220.220"],
    "bridge": "none"
}

This file is in "C:\ProgramData\Docker\config" as per this documentation.

Running docker info outputs:

Client:
 Debug Mode: false
 Plugins:
  cluster: Manage Docker clusters (Docker Inc., v1.2.0)

Server:
 Containers: 5
  Running: 0
  Paused: 0
  Stopped: 5
 Images: 3
 Server Version: 19.03.4
 Storage Driver: windowsfilter (windows) lcow (linux)
  Windows:
  LCOW:
 Logging Driver: json-file
 Plugins:
  Volume: local
  Network: ics internal l2bridge l2tunnel nat null overlay private transparent
  Log: awslogs etwlogs fluentd gcplogs gelf json-file local logentries splunk syslog
 Swarm: inactive
 Default Isolation: process
 Kernel Version: 10.0 17763 (17763.1.amd64fre.rs5_release.180914-1434)
 Operating System: Windows Server 2019 Datacenter Version 1809 (OS Build 17763.864)
 OSType: windows
 Architecture: x86_64
 CPUs: 2
 Total Memory: 8GiB
 Name: xxxxxxxx
 ID: GMKH:37MH:LDBL:AXQA:DYNK:342Y:A2AR:OLJP:WRJM:YQV2:4XZA:XJCR
 Docker Root Dir: C:\ProgramData\docker
 Debug Mode: false
 Registry: https://index.docker.io/v1/
 Labels:
 Experimental: true
 Insecure Registries:
  127.0.0.0/8
 Live Restore Enabled: false

Running docker network ls outputs:

NETWORK ID          NAME                DRIVER              SCOPE
3c451e980ddd        nat                 nat                 local
c2d54c8da069        none                null                local

Running docker network inspect nat outputs:

[
    {
        "Name": "nat",
        "Id": "3c451e980dddda1b46005caba457f56efb4aba610668c5d58f7c3cc839604347",
        "Created": "2019-11-12T22:07:47.6443712Z",
        "Scope": "local",
        "Driver": "nat",
        "EnableIPv6": false,
        "IPAM": {
            "Driver": "windows",
            "Options": null,
            "Config": [
                {
                    "Subnet": "172.20.160.0/20",
                    "Gateway": "172.20.160.1"
                }
            ]
        },
        "Internal": false,
        "Attachable": false,
        "Ingress": false,
        "ConfigFrom": {
            "Network": ""
        },
        "ConfigOnly": false,
        "Containers": {},
        "Options": {
            "com.docker.network.windowsshim.hnsid": "8991C564-50DB-4AE0-9C75-7B117787CC7E",
            "com.docker.network.windowsshim.networkname": "nat"
        },
        "Labels": {}
    }
]

Contents of Dockerfile.amd64.debug are:

FROM mcr.microsoft.com/dotnet/core/runtime:3.0.0-buster-slim AS base

RUN apt-get update && \
    apt-get install -y --no-install-recommends unzip procps && \
    rm -rf /var/lib/apt/lists/*

RUN useradd -ms /bin/bash moduleuser
USER moduleuser
RUN curl -sSL https://aka.ms/getvsdbgsh | bash /dev/stdin -v latest -l ~/vsdbg

FROM mcr.microsoft.com/dotnet/core/sdk AS build-env
WORKDIR /app

COPY *.csproj ./
RUN dotnet restore

COPY . ./
RUN dotnet publish -c Debug -o out

FROM gcc:7 AS build-env-2
WORKDIR /app

# copy .c and .h file
COPY *.c ./
COPY *.h ./

# build
RUN gcc -shared -o libcomWrapper.so -fPIC comWrapper.c

FROM base
WORKDIR /app
COPY --from=build-env /app/out ./
COPY --from=build-env-2 /app/libcomWrapper.so /usr/lib/

ENTRYPOINT ["dotnet", "iotedgeModbus.dll"]

My deployment.debug.template.json file has the same structure as this example.

Attempted solutions

I have tried the following in an attempt to rectify the issue:

Confirmed that the host can ping google.com, deb.debian.org, and security.debian.org.
Confirmed that the host machine successfully returns nslookup results for google.com, deb.debian.org, and security.debian.org.
Updated daemon.json file with DNS entries for Google DNS, OpenDNS, and host adapter DNS then restarted the docker service to test connectivity.
Specified the adapter to use in the docker build command with the --network flag, I have tried both the nat and none networks.
Setting the DNS use to Google DNS and OpenDNS servers on the vEthernet (nat) adapter on the host machine.
Specifying the DNS servers to use with the --dns flag (seems only be available for dockerd rather than docker.
Setting the InterfaceMetric of the adapter the host uses to connect to the internet to be lower than those of the other adapters, as per this comment.
Confirmed that host networking does not work for Docker EE on Windows Server as per the documentation.
Attempted to create a bridge network with docker network create -d bridge mynetwork but encountered: "Error response from daemon: could not find plugin bridge in v1 plugin registry: plugin not found".
Created a transparent network adapter using docker network create -d transparent MyNetwork but since docker build does not complete, I cannot attach it to a container.

Solution

Open the daemon configuration and add the DNS 8.8.8.8 in json format. Then restart the docker daemon. Apt get will work. The entry is

{
    "dns": ["8.8.8.8"]
}