Launching confluent local kafka start fails with Error: runtime error: index out of range [0] with length 0

[mcascallares]

When launching 'confluent local kafka start', I get this error:

confluent local -vvvv kafka start
The local commands are intended for a single-node development environment only, NOT for production usage. See more: https://docs.confluent.io/current/cli/index.html


Pulling from confluentinc/confluent-local
Digest: sha256:8e391de42cfcd3498e7317dcf159790f1f1cc3f3ffce900b30d7da23888687fd
Status: Image is up to date for confluentinc/confluent-local:latest
2023-09-19T10:04:18.214+0200 [TRACE] Successfully pulled Confluent Local image
Error: runtime error: index out of range [0] with length 0

Find below my CLI information

confluent - Confluent CLI

Version:     v3.33.0
Git Ref:     53da89b2
Build Date:  2023-09-14T22:43:04Z
Go Version:  go1.21.0 X:boringcrypto (darwin/amd64)
Development: false

Find below my docker environment information

Client:
 Version:    24.0.6
 Context:    desktop-linux
 Debug Mode: false

Server:
 Containers: 0
  Running: 0
  Paused: 0
  Stopped: 0
 Images: 59
 Server Version: 24.0.6
 Storage Driver: overlay2
  Backing Filesystem: extfs
  Supports d_type: true
  Using metacopy: false
  Native Overlay Diff: true
  userxattr: false
 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 logentries splunk syslog
 Swarm: inactive
 Runtimes: io.containerd.runc.v2 runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: 8165feabfdfe38c65b599c4993d227328c231fca
 runc version: v1.1.8-0-g82f18fe
 init version: de40ad0
 Security Options:
  seccomp
   Profile: unconfined
  cgroupns
 Kernel Version: 6.3.13-linuxkit
 Operating System: Docker Desktop
 OSType: linux
 Architecture: x86_64
 CPUs: 2
 Total Memory: 7.769GiB
 Name: docker-desktop
 ID: 746e542e-f404-4449-b366-ba2a54e391a8
 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
 Experimental: false
 Insecure Registries:
  hubproxy.docker.internal:5555
  127.0.0.0/8
 Live Restore Enabled: false

WARNING: daemon is not using the default seccomp profile

[mcascallares]

Executing the same image "manually" works

docker run -d \
  --name confluent-local \
  -p 9092:9092 \
  -p 8082:8082 \
  -p 29092:29093 \
  confluentinc/confluent-local

[MuweiHe]

Might be an issue with setting up ports to use in confluent local. can you reproduce the state of error and share with me the content of ~/.confluent/config.json, the part close to the end of file where it says local_ports? e.g.

"local_ports": {
    "broker_ports": [
      "53229"
    ],
    "controller_ports": [
      "53230"
    ],
    "kafka_rest_port": "8082",
    "plaintext_ports": [
      "53228"
    ]
  }

And if they're not empty, can you check if any of those 4 ports are bind with other processes?

[mcascallares]

Thanks for your reply MuweiHe

I reproduced the same error, and checking ~/.confluent/config.json the mentioned ports were:

  "local_ports": {
    "broker_ports": null,
    "controller_ports": null,
    "kafka_rest_port": "8082",
    "plaintext_ports": null
  },

I never edited that file, so not sure why those values were null.

After that, I edited the file using the values you showed and now the error is a different one:

Error: Error response from daemon: Ports are not available: exposing port TCP localhost:8082 -> 0.0.0.0:0: listen tcp: lookup <nil>: no such host

Note that there are no other containers running or using mentioned ports.

[MuweiHe]

Thanks! Looks like CLI failed to assign a free port to broker ports etc.
Does running confluent local kafka start --brokers 1~4 (specifying the number of brokers) work for you?

[MuweiHe]

Although editing the file after running start would not work, as those values should be configured before starting the container.

[MuweiHe]

Other possible items you could look into: the freeport package tries to identify free ports by binding to a port number of 0 (which lets the OS pick a free port) and then immediately releasing it. If there're concurrent Go applications running / firewall or network settings like in a container or cloud setup, the process of detecting free ports might fail.

[MuweiHe]

Hi Matias Cascallares (@mcascallares) Do you still see Error: Error response from daemon: Ports are not available: exposing port TCP localhost:8082 -> 0.0.0.0:0: listen tcp: lookup <nil>: no such host? One temp relief is to downgrade docker to 4.22.0 or earlier while i investigate further

[mcascallares]

Hi MuweiHe! Thanks for reaching out.

I tested it disabling GlobalProtect, no existing Docker containers, and still the same issue. The workaround that you mentioned, using Docker 4.22.0 earlier, does make sense since used to work before, but I haven't tested it yet.

[MuweiHe]

Hi Matias Cascallares (@mcascallares) i have included a fix for this issue in today's release (should be v3.41.0). turned out new docker have stopped auto mapping localhost to 0.0.0.0 by looking up in etc/hosts, so i needed to explicitly declare a 0.0.0.0 host. Can you help verify v.3.41.0 works for you or not? thanks!
(the release should be out later today

[mcascallares]

Hi MuweiHe
I just updated the confluent CLI and worked perfectly.

Thank you so much!