[Bug]: KafkaContainer in a network (bad KAFKA_ADVERTISED_LISTENERS ?)

[SebastienDegodez]

Testcontainers version

4.1.0

Using the latest Testcontainers version?

Yes

Host OS

MacOs

Host arch

ARM

.NET version

8.0.404

Docker version

Client:
 Version:           27.3.1
 API version:       1.47
 Go version:        go1.22.7
 Git commit:        ce12230
 Built:             Fri Sep 20 11:38:18 2024
 OS/Arch:           darwin/arm64
 Context:           desktop-linux

Server: Docker Desktop 4.36.0 (175267)
 Engine:
  Version:          27.3.1
  API version:      1.47 (minimum version 1.24)
  Go version:       go1.22.7
  Git commit:       41ca978
  Built:            Fri Sep 20 11:41:19 2024
  OS/Arch:          linux/arm64
  Experimental:     false
 containerd:
  Version:          1.7.21
  GitCommit:        472731909fa34bd7bc9c087e4c27943f9835f111
 runc:
  Version:          1.1.13
  GitCommit:        v1.1.13-0-g58aa920
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

Docker info

Client:
 Version:    27.3.1
 Context:    desktop-linux
 Debug Mode: false
 Plugins:
  ai: Ask Gordon - Docker Agent (Docker Inc.)
    Version:  v0.1.0
    Path:     /Users/sebastiendegodez/.docker/cli-plugins/docker-ai
  buildx: Docker Buildx (Docker Inc.)
    Version:  v0.18.0-desktop.2
    Path:     /Users/sebastiendegodez/.docker/cli-plugins/docker-buildx
  compose: Docker Compose (Docker Inc.)
    Version:  v2.30.3-desktop.1
    Path:     /Users/sebastiendegodez/.docker/cli-plugins/docker-compose
  debug: Get a shell into any image or container (Docker Inc.)
    Version:  0.0.37
    Path:     /Users/sebastiendegodez/.docker/cli-plugins/docker-debug
  desktop: Docker Desktop commands (Alpha) (Docker Inc.)
    Version:  v0.0.15
    Path:     /Users/sebastiendegodez/.docker/cli-plugins/docker-desktop
  dev: Docker Dev Environments (Docker Inc.)
    Version:  v0.1.2
    Path:     /Users/sebastiendegodez/.docker/cli-plugins/docker-dev
  extension: Manages Docker extensions (Docker Inc.)
    Version:  v0.2.27
    Path:     /Users/sebastiendegodez/.docker/cli-plugins/docker-extension
  feedback: Provide feedback, right in your terminal! (Docker Inc.)
    Version:  v1.0.5
    Path:     /Users/sebastiendegodez/.docker/cli-plugins/docker-feedback
  init: Creates Docker-related starter files for your project (Docker Inc.)
    Version:  v1.4.0
    Path:     /Users/sebastiendegodez/.docker/cli-plugins/docker-init
  sbom: View the packaged-based Software Bill Of Materials (SBOM) for an image (Anchore Inc.)
    Version:  0.6.0
    Path:     /Users/sebastiendegodez/.docker/cli-plugins/docker-sbom
  scout: Docker Scout (Docker Inc.)
    Version:  v1.15.0
    Path:     /Users/sebastiendegodez/.docker/cli-plugins/docker-scout

Server:
 Containers: 6
  Running: 1
  Paused: 0
  Stopped: 5
 Images: 12
 Server Version: 27.3.1
 Storage Driver: overlayfs
  driver-type: io.containerd.snapshotter.v1
 Logging Driver: json-file
 Cgroup Driver: cgroupfs
 Cgroup Version: 2
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local splunk syslog
 Swarm: inactive
 Runtimes: io.containerd.runc.v2 runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: 472731909fa34bd7bc9c087e4c27943f9835f111
 runc version: v1.1.13-0-g58aa920
 init version: de40ad0
 Security Options:
  seccomp
   Profile: unconfined
  cgroupns
 Kernel Version: 6.10.14-linuxkit
 Operating System: Docker Desktop
 OSType: linux
 Architecture: aarch64
 CPUs: 12
 Total Memory: 7.653GiB
 Name: docker-desktop
 ID: b7a940eb-57f9-4a02-bcae-d2f3d13250ab
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 HTTP Proxy: http.docker.internal:3128
 HTTPS Proxy: http.docker.internal:3128
 No Proxy: hubproxy.docker.internal
 Labels:
  com.docker.desktop.address=unix:///Users/sebastiendegodez/Library/Containers/com.docker.docker/Data/docker-cli.sock
 Experimental: false
 Insecure Registries:
  hubproxy.docker.internal:5555
  127.0.0.0/8
 Live Restore Enabled: false

What happened?

When you create a network, and places two containers on custom networks with a kafka container and another container, kafdrop for example. There is an error.

After investigating, I think the implementation of StartupCallback is not good.

The code actually use Hostname, the test process resolves the container address '127.0.0.1'.

startupScript.Append("export KAFKA_ADVERTISED_LISTENERS=PLAINTEXT://" + container.Hostname + ":" + container.GetMappedPublicPort(KafkaBuilder.KafkaPort) + ",BROKER://" + container.IpAddress + ":" + KafkaBuilder.BrokerPort);

After

startupScript.Append("export KAFKA_ADVERTISED_LISTENERS=PLAINTEXT://" + container.IpAddress + ":" + KafkaBuilder.KafkaPort + ",BROKER://" + container.IpAddress + ":" + KafkaBuilder.BrokerPort);

KAFKA_ADVERTISED_LISTENERS specifies the IP addresses and ports that Kafka clients should use to connect to the brokers.

Here is a sample code with a KafkaBuilder and a ContainerBuilder ( kafdrop) to reproduce this error:

var network = new NetworkBuilder().Build();

var kafdropContainer = new ContainerBuilder()
    .WithImage("obsidiandynamics/kafdrop:latest")
    .WithPortBinding(9000, 9000)
    .WithNetwork(network)
    .WithNetworkAliases("kafdrop")
    .WithEnvironment("KAFKA_BROKERCONNECT", "kafka:9092")
    .Build();

this._kafkaContainer = new KafkaBuilder()
    .WithImage("confluentinc/cp-kafka:7.8.0")
    .WithPortBinding(9092, KafkaBuilder.KafkaPort)
    .WithPortBinding(9093, KafkaBuilder.BrokerPort)
    .WithNetwork(network)
    .WithNetworkAliases("kafka")
    .Build();
await kafdropContainer.StartAsync();
// Start the Kafka container
await this._kafkaContainer.StartAsync();

Thanks,

Relevant log output

Additional information

No response

[SebastienDegodez]

After further investigation, the host name is really important for the testing process. I think a better solution would be to add a new method in builder. This method would allow adding another listener, protocole and an advertised listener.

[HofmeisterAn]

Thanks for creating the issue. I think it makes sense to look into Java's implementation and align it, if possible, with the .NET implementation. I just took a quick look, and indeed, they configure the environment variable differently.

[SebastienDegodez]

Thanks for creating the issue. I think it makes sense to look into Java's implementation and align it, if possible, with the .NET implementation. I just took a quick look, and indeed, they configure the environment variable differently.

Hello, you can find my help here: feat(kafka): Add network support for Kafka container #1316