Support for --add-host host.docker.internal:host-gateway

[adamretter]

Since Docker 20.10.0 it is now possible to specify --add-host host.docker.internal:host-gateway which will add an entry to the /etc/hosts file of the container like:

172.17.0.1      host.docker.internal

Which makes it easier for the Container to communicate with the Host.

I tried to use the extraHosts option of the docker-maven-plugin like this:

 <extraHosts>
    <host>host.docker.internal:host-gateway</host>
</extraHosts>

Unfortunately that yields the following error:

Caused by: java.lang.IllegalArgumentException: unable to resolve ip address for host-gateway
    at io.fabric8.maven.docker.access.ContainerHostConfig.extraHosts (ContainerHostConfig.java:97)
    at io.fabric8.maven.docker.service.RunService.createContainerHostConfig (RunService.java:420)
    at io.fabric8.maven.docker.service.RunService.createContainerConfig (RunService.java:379)
    at io.fabric8.maven.docker.service.RunService.createContainer (RunService.java:152)
    at io.fabric8.maven.docker.service.RunService.createAndStartContainer (RunService.java:190)
    at io.fabric8.maven.docker.service.helper.StartContainerExecutor.startContainer (StartContainerExecutor.java:47)
    at io.fabric8.maven.docker.StartMojo.lambda$startImage$0 (StartMojo.java:298)
    at com.google.common.util.concurrent.TrustedListenableFutureTask$TrustedFutureInterruptibleTask.runInterruptibly (TrustedListenableFutureTask.java:125)
    at com.google.common.util.concurrent.InterruptibleTask.run (InterruptibleTask.java:69)
    at com.google.common.util.concurrent.TrustedListenableFutureTask.run (TrustedListenableFutureTask.java:78)
    at java.util.concurrent.Executors$RunnableAdapter.call (Executors.java:511)
    at java.util.concurrent.FutureTask.run (FutureTask.java:266)
    at com.google.common.util.concurrent.MoreExecutors$DirectExecutorService.execute (MoreExecutors.java:321)
    at java.util.concurrent.ExecutorCompletionService.submit (ExecutorCompletionService.java:181)
    at io.fabric8.maven.docker.StartMojo.startImage (StartMojo.java:296)
    at io.fabric8.maven.docker.StartMojo.executeInternal (StartMojo.java:165)
    at io.fabric8.maven.docker.AbstractDockerMojo.execute (AbstractDockerMojo.java:280)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:137)
    ...
Caused by: java.net.UnknownHostException: host-gateway: Name or service not known
    at java.net.Inet6AddressImpl.lookupAllHostAddr (Native Method)
    at java.net.InetAddress$2.lookupAllHostAddr (InetAddress.java:929)
    at java.net.InetAddress.getAddressesFromNameService (InetAddress.java:1324)
    at java.net.InetAddress.getAllByName0 (InetAddress.java:1277)
    at java.net.InetAddress.getAllByName (InetAddress.java:1193)
    at java.net.InetAddress.getAllByName (InetAddress.java:1127)
    at java.net.InetAddress.getByName (InetAddress.java:1077)
    at io.fabric8.maven.docker.access.ContainerHostConfig.extraHosts (ContainerHostConfig.java:95)
    at io.fabric8.maven.docker.service.RunService.createContainerHostConfig (RunService.java:420)
    at io.fabric8.maven.docker.service.RunService.createContainerConfig (RunService.java:379)
    at io.fabric8.maven.docker.service.RunService.createContainer (RunService.java:152)
    at io.fabric8.maven.docker.service.RunService.createAndStartContainer (RunService.java:190)
    at io.fabric8.maven.docker.service.helper.StartContainerExecutor.startContainer (StartContainerExecutor.java:47)
    at io.fabric8.maven.docker.StartMojo.lambda$startImage$0 (StartMojo.java:298)
    at com.google.common.util.concurrent.TrustedListenableFutureTask$TrustedFutureInterruptibleTask.runInterruptibly (TrustedListenableFutureTask.java:125)
    at com.google.common.util.concurrent.InterruptibleTask.run (InterruptibleTask.java:69)
    at com.google.common.util.concurrent.TrustedListenableFutureTask.run (TrustedListenableFutureTask.java:78)
    at java.util.concurrent.Executors$RunnableAdapter.call (Executors.java:511)
    at java.util.concurrent.FutureTask.run (FutureTask.java:266)
    at com.google.common.util.concurrent.MoreExecutors$DirectExecutorService.execute (MoreExecutors.java:321)
    at java.util.concurrent.ExecutorCompletionService.submit (ExecutorCompletionService.java:181)
    at io.fabric8.maven.docker.StartMojo.startImage (StartMojo.java:296)
    at io.fabric8.maven.docker.StartMojo.executeInternal (StartMojo.java:165)
    at io.fabric8.maven.docker.AbstractDockerMojo.execute (AbstractDockerMojo.java:280)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:137)
    ...

Info

• docker-maven-plugin version : 0.39.0
• Maven version (mvn -v) :

Apache Maven 3.8.4 (9b656c72d54e5bacbed989b64718c159fe39b537)
Maven home: /home/aretter/.sdkman/candidates/maven/current
Java version: 1.8.0_312, vendor: BellSoft, runtime: /home/aretter/.sdkman/candidates/java/8.0.312.fx-librca/jre
Default locale: en_GB, platform encoding: UTF-8
OS name: "linux", version: "5.13.0-28-generic", arch: "amd64", family: "unix"

• Docker version : 20.10.12, build e91ed57

[adamretter]

Thank you :-)