How-To configure IPv6-only

[Chem0908]

i configure the container via Dockge and have trouble to run this with IPv6 only.
Docker seems to work with IPv6 becouse i can reach the WebInteface of Dockge.

I think the problem is the configuration inside the image. An plain alpine container can ping to purpurmc.com
confurations:

deamon.js

{
  "ipv6": true,
  "fixed-cidr-v6": "fd00::/80"
}

compose.yml

services:
  mc:
    image: itzg/minecraft-server
    tty: true
    stdin_open: true
    ports:
      - "[::]:25566:25566"
    environment:
      EULA: "TRUE"
      TYPE: PURPUR
      VERSION: 1.20.5
      JVM_DD_OPTS: java.net.preferIPv6Addresses=true
    volumes:
      # attach the relative directory 'data' to the container's /data path
      - ./data:/data
networks:
  dockge_default:
    enable_ipv6: true
    external: true

Error Message

minecraft-server-mc-1  | [init] ERROR: failed to download Purpur
minecraft-server-mc-1  | [init] Running as uid=1000 gid=1000 with /data as 'drwxr-xr-x 2 1000 1000 5 Jun 10 16:39 /data'
minecraft-server-mc-1  | [init] Resolving type given PURPUR
minecraft-server-mc-1  | [mc-image-helper] 18:13:11.075 ERROR : 'install-purpur' command failed. Version is 1.38.16
minecraft-server-mc-1  | reactor.core.Exceptions$ReactiveException: java.net.UnknownHostException: Failed to resolve 'api.purpurmc.org' [A(1)]
minecraft-server-mc-1  |        at reactor.core.Exceptions.propagate(Exceptions.java:408)
minecraft-server-mc-1  |        at reactor.core.publisher.BlockingSingleSubscriber.blockingGet(BlockingSingleSubscriber.java:101)
minecraft-server-mc-1  |        at reactor.core.publisher.Mono.block(Mono.java:1712)
minecraft-server-mc-1  |        at me.itzg.helpers.purpur.InstallPurpurCommand.useCoordinates(InstallPurpurCommand.java:147)
minecraft-server-mc-1  |        at me.itzg.helpers.purpur.InstallPurpurCommand.call(InstallPurpurCommand.java:104)
minecraft-server-mc-1  |        at me.itzg.helpers.purpur.InstallPurpurCommand.call(InstallPurpurCommand.java:35)
minecraft-server-mc-1  |        at picocli.CommandLine.executeUserObject(CommandLine.java:2045)
minecraft-server-mc-1  |        at picocli.CommandLine.access$1500(CommandLine.java:148)
minecraft-server-mc-1  |        at picocli.CommandLine$RunLast.executeUserObjectOfLastSubcommandWithSameParent(CommandLine.java:2465)
minecraft-server-mc-1  |        at picocli.CommandLine$RunLast.handle(CommandLine.java:2457)
minecraft-server-mc-1  |        at picocli.CommandLine$RunLast.handle(CommandLine.java:2419)
minecraft-server-mc-1  |        at picocli.CommandLine$AbstractParseResultHandler.execute(CommandLine.java:2277)
minecraft-server-mc-1  |        at picocli.CommandLine$RunLast.execute(CommandLine.java:2421)
minecraft-server-mc-1  |        at picocli.CommandLine.execute(CommandLine.java:2174)
minecraft-server-mc-1  |        at me.itzg.helpers.McImageHelper.main(McImageHelper.java:159)
minecraft-server-mc-1  |        Suppressed: java.lang.Exception: #block terminated with an error
minecraft-server-mc-1  |                at reactor.core.publisher.BlockingSingleSubscriber.blockingGet(BlockingSingleSubscriber.java:103)
minecraft-server-mc-1  |                ... 13 common frames omitted
minecraft-server-mc-1  | Caused by: java.net.UnknownHostException: Failed to resolve 'api.purpurmc.org' [A(1)]
minecraft-server-mc-1  |        at io.netty.resolver.dns.DnsResolveContext.finishResolve(DnsResolveContext.java:1151)
minecraft-server-mc-1  |        at io.netty.resolver.dns.DnsResolveContext.tryToFinishResolve(DnsResolveContext.java:1098)
minecraft-server-mc-1  |        at io.netty.resolver.dns.DnsResolveContext.query(DnsResolveContext.java:457)
minecraft-server-mc-1  |        at io.netty.resolver.dns.DnsResolveContext.access$700(DnsResolveContext.java:69)
minecraft-server-mc-1  |        at io.netty.resolver.dns.DnsResolveContext$2.operationComplete(DnsResolveContext.java:526)
minecraft-server-mc-1  |        at io.netty.util.concurrent.DefaultPromise.notifyListener0(DefaultPromise.java:590)
minecraft-server-mc-1  |        at io.netty.util.concurrent.DefaultPromise.notifyListeners0(DefaultPromise.java:583)
minecraft-server-mc-1  |        at io.netty.util.concurrent.DefaultPromise.notifyListenersNow(DefaultPromise.java:559)
minecraft-server-mc-1  |        at io.netty.util.concurrent.DefaultPromise.notifyListeners(DefaultPromise.java:492)
minecraft-server-mc-1  |        at io.netty.util.concurrent.DefaultPromise.setValue0(DefaultPromise.java:636)
minecraft-server-mc-1  |        at io.netty.util.concurrent.DefaultPromise.setFailure0(DefaultPromise.java:629)
minecraft-server-mc-1  |        at io.netty.util.concurrent.DefaultPromise.tryFailure(DefaultPromise.java:118)
minecraft-server-mc-1  |        at io.netty.resolver.dns.DnsQueryContext.finishFailure(DnsQueryContext.java:380)
minecraft-server-mc-1  |        at io.netty.resolver.dns.DnsQueryContext$5.run(DnsQueryContext.java:315)
minecraft-server-mc-1  |        at io.netty.util.concurrent.PromiseTask.runTask(PromiseTask.java:98)
minecraft-server-mc-1  |        at io.netty.util.concurrent.ScheduledFutureTask.run(ScheduledFutureTask.java:153)
minecraft-server-mc-1  |        at io.netty.util.concurrent.AbstractEventExecutor.runTask(AbstractEventExecutor.java:173)
minecraft-server-mc-1  |        at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:166)
minecraft-server-mc-1  |        at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:470)
minecraft-server-mc-1  |        at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:408)
minecraft-server-mc-1  |        at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997)
minecraft-server-mc-1  |        at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
minecraft-server-mc-1  |        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
minecraft-server-mc-1  |        at java.base/java.lang.Thread.run(Unknown Source)
minecraft-server-mc-1  | Caused by: io.netty.resolver.dns.DnsNameResolverTimeoutException: [15068: /127.0.0.11:53] DefaultDnsQuestion(api.purpurmc.org. IN A) query '15068' via UDP timed out after 5000 milliseconds (no stack trace available)
minecraft-server-mc-1  | [init] ERROR: failed to download Purpur
minecraft-server-mc-1 exited with code 1

[itzg]

Docker seems to work with IPv6 becouse i can reach the WebInteface of Dockge.

That doesn't confirm anything related to the DNS lookup failure in your logs.

I think the problem is the configuration inside the image.

What configuration do you suspect? There is no configuration related to networking in this repo.

An plain alpine container can ping to purpurmc.com

The image you're using is based on Ubuntu, not Alpine. Specifically it's based on the image eclipse-temurin:21-jre, so that's the one you should test with.

[itzg]

Thanks for confirming that. Unfortunately there's nothing I can fix since the issue relates to the upstream image you tested.

[Chem0908]

No Problem. Thats right. When i use java with ipv6 i need to add this option to the jar executable:
-Djava.net.preferIPv6Stack=true

is it possible that you can implement this as an global Environment variable? Here is an thread that might be help
https://stackoverflow.com/questions/20262587/where-to-set-java-net-preferipv6addresses-true

For the start parameter of the jar i handled it with the dd options. But it also has problems by downloading the reqested jar. So eventually it is possible to add this in the method where the download is Happening

[itzg]

I believe it'll work to pass that via JAVA_TOOL_OPTIONS env var since that's a standard JVM thing.

[Chem0908]

I got some new infos. The JAVA_TOOL_OPTIONS was not the problem. It seems that there was realy an underlaying networking problem which i can fixed with the following configurations:

compose.yaml

services:
  mc:
    image: itzg/minecraft-server
    tty: true
    stdin_open: true
    ports:
      - "[::]:25566:25566"
    environment:
      EULA: "TRUE"
      TYPE: PURPUR
      VERSION: 1.20.6
      SERVER_PORT: 25566
      JVM_DD_OPTS: java.net.preferIPv6Addresses=true
    volumes:
      # attach the relative directory 'data' to the container's /data path
      - ./data:/data
    networks:
      mc_default:
        ipv6_address: fd00:2::2 # Replace with your desired IPv6 address
networks:
  mc_default:
    driver: bridge
    enable_ipv6: true # Enable IPv6 for the network
    ipam:
      driver: default
      config:
        - subnet: fd00:2::/64

deamon.js

{
    "ipv6": true,
    "fixed-cidr-v6": "2001:db8:1::/64",
    "experimental": true,
    "ip6tables": true
}

Docker Console

mc-mc-1  | [init] Running as uid=1000 gid=1000 with /data as 'drwxr-xr-x 12 1000 1000 31 Jun 14 07:13 /data'
mc-mc-1  | [init] Resolving type given PURPUR
mc-mc-1  | [mc-image-helper] 07:41:21.120 INFO  : Resolved Purpur version 1.20.6 build 2232
mc-mc-1  | [mc-image-helper] 07:41:21.159 INFO  : The file /data/purpur-1.20.6-2232.jar is already up to date
mc-mc-1  | [mc-image-helper] 07:41:24.490 INFO  : Created/updated 1 property in /data/server.properties
mc-mc-1  | [init] Setting initial memory to 1G and max to 1G
mc-mc-1  | [init] Starting the Minecraft server...
mc-mc-1  | Starting org.bukkit.craftbukkit.Main
mc-mc-1  | System Info: Java 21 (OpenJDK 64-Bit Server VM 21.0.3+9-LTS) Host: Linux 6.8.4-3-pve (amd64)
mc-mc-1  | Loading libraries, please wait...
mc-mc-1  | [07:41:41 INFO]: Environment: Environment[sessionHost=https://sessionserver.mojang.com, servicesHost=https://api.minecraftservices.com, name=PROD]
mc-mc-1  | [07:41:43 INFO]: Loaded 1175 recipes
mc-mc-1  | [07:41:43 INFO]: Loaded 1276 advancements
mc-mc-1  | [07:41:44 INFO]: Starting minecraft server version 1.20.6
mc-mc-1  | [07:41:44 INFO]: Loading properties
mc-mc-1  | [07:41:44 INFO]: This server is running Purpur version 1.20.6-2232-ver/1.20.6@f1c87e4 (2024-06-14T00:09:44Z) (Implementing API version 1.20.6-R0.1-SNAPSHOT)
mc-mc-1  | [07:41:45 INFO]: Server Ping Player Sample Count: 12
mc-mc-1  | [07:41:45 INFO]: Using 4 threads for Netty based IO
mc-mc-1  | [07:41:45 INFO]: [ChunkTaskScheduler] Chunk system is using 1 I/O threads, 1 worker threads, and gen parallelism of 1 threads
[07:41:46 INFO]: Default game type: SURVIVAL
[07:41:46 INFO]: Generating keypair
[07:41:46 INFO]: Starting Minecraft server on *:25565
[07:41:46 INFO]: Using epoll channel type
[07:41:46 INFO]: Paper: Using libdeflate (Linux x86_64) compression from Velocity.
[07:41:46 INFO]: Paper: Using OpenSSL 3.0.x (Linux x86_64) cipher from Velocity.
[07:41:46 INFO]: [spark] Loading server plugin spark v1.10.71
[07:41:46 INFO]: Server permissions file permissions.yml is empty, ignoring it
[07:41:46 INFO]: Preparing level "world"
[07:41:47 INFO]: Preparing start region for dimension minecraft:overworld
[07:41:48 INFO]: Time elapsed: 1328 ms
[07:41:48 INFO]: Preparing start region for dimension minecraft:the_nether
[07:41:49 INFO]: Time elapsed: 201 ms
[07:41:49 INFO]: Preparing start region for dimension minecraft:the_end
[07:41:49 INFO]: Time elapsed: 115 ms
[07:41:49 INFO]: [spark] Enabling spark v1.10.71
[07:41:50 INFO]: [spark] Using Paper ServerTickStartEvent for tick monitoring
[07:41:50 INFO]: [spark] Starting background profiler...
[07:41:51 INFO]: Starting remote control listener
[07:41:51 INFO]: Thread RCON Listener started
[07:41:51 INFO]: RCON running on 0.0.0.0:25575
[07:41:51 INFO]: Running delayed init tasks
[07:41:51 INFO]: Done (7.161s)! For help, type "help"

[Chem0908]

do you have an tip how i can enter commands inside the contaier for example op [player] without staticly set the op list over enviroment

[itzg]

https://docker-minecraft-server.readthedocs.io/en/latest/commands/