Unable to create websocket server

[tetofonta]

Environment

OS Version: Ubuntu Jammy

• Source or binary build?

ign launch --version
5.3.0

Description

• Expected behavior: Websocket server starts and allows for connection to gazebo running in background
• Actual behavior: Startup fails to create the websocket server.

ign launch -v 4 websocket.ign
[Dbg] [Manager.cc:1137] Loading plugin. Name[ignition::launch::WebsocketServer] File[ignition-launch-websocket-server]
[Dbg] [WebsocketServer.cc:403] Using port[9002]
[Wrn] [WebsocketServer.cc:548] Partial SSL configuration specified. Please specify:     <ssl>
          <cert_file>PATH_TO_CERT_FILE</cert_file>
          <private_key_file>PATH_TO_KEY_FILE</private_key_file>
        </ssl>.
Continuing without SSL.
[Err] [WebsocketServer.cc:565] Unable to create websocket server

Steps to reproduce

1. Build the following docker image with the command docker buildx build . -t gazebo:fortress -f Dockerfile.gazebo:

    FROM ubuntu:jammy

ENV DEBIAN_FRONTEND noninteractive
ENV GZ_VERSION fortress

RUN apt-get update
RUN apt-get install -y lsb-release wget gnupg
RUN wget https://packages.osrfoundation.org/gazebo.gpg -O /usr/share/keyrings/pkgs-osrf-archive-keyring.gpg
RUN echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/pkgs-osrf-archive-keyring.gpg] http://packages.osrfoundation.org/gazebo/ubuntu-stable $(lsb_release -cs) main" | tee /etc/apt/sources.list.d/gazebo-stable.list > /dev/null
RUN apt-get update
RUN apt-get -y install gz-${GZ_VERSION}

ENTRYPOINT [ "ign" ]
CMD ["sim"]

2. Run a new container instance docker run --rm --net host --entrypoint bash -it gazebo:fortress
3. Run gazebo in the background ign gazebo -v 4 -s -r fuel.sdf &
4. Try run gz-launch

# echo "<?xml version='1.0'?>
<ignition version='1.0'>
  <plugin name='ignition::launch::WebsocketServer'
          filename='ignition-launch-websocket-server'>
    <port>9002</port>
  </plugin>
</ignition>" > websocket.ign
# ign launch -v 4 websocket.ign

Output

Log resulting from the gazebo instance

[Msg] Ignition Gazebo Server v6.16.0
[Msg] Loading SDF world file[/usr/share/ignition/ignition-gazebo6/worlds/fuel.sdf].
[Msg] Downloading model [https://fuel.gazebosim.org/openrobotics/models/double pendulum with base]
[Dbg] [FuelClient.cc:2002] Downloading from a referral link [https://gz-fuel-resources-production.s3.amazonaws.com/OpenRobotics/90a80ecc-8b16-4d4d-be30-ba79fd7d92be/.zips/5.zip?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAS5OHIRKDBY6VUUFF%2F20240429%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20240429T140808Z&X-Amz-Expires=3600&X-Amz-SignedHeaders=host&X-Amz-Signature=9a25910776ef0c4d1e7831cb4462d6a92c0a2c9a2b1d18a4d5e41ada50f29570]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/double pendulum with base/5/model-1_3.sdf]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/double pendulum with base/5/model-1_4.sdf]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/double pendulum with base/5/model.config]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/double pendulum with base/5/model.sdf]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/double pendulum with base/5/thumbnails/1.png]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/double pendulum with base/5/thumbnails/2.png]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/double pendulum with base/5/thumbnails/3.png]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/double pendulum with base/5/thumbnails/4.png]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/double pendulum with base/5/thumbnails/5.png]
[Msg] Downloading model [https://fuel.gazebosim.org/openrobotics/models/backpack]
[Dbg] [FuelClient.cc:2002] Downloading from a referral link [https://gz-fuel-resources-production.s3.amazonaws.com/OpenRobotics/14d366b4-1ce7-41c3-baa4-45e2daf212f6/.zips/3.zip?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAS5OHIRKDBY6VUUFF%2F20240429%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20240429T140810Z&X-Amz-Expires=3600&X-Amz-SignedHeaders=host&X-Amz-Signature=bbeb18f83bd8391648e06f6b5c39cc6b1345a16538e71f8b4a6ff2a754f7797a]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/backpack/3/materials/textures/Backpack.png]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/backpack/3/meshes/Backpack.dae]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/backpack/3/model.config]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/backpack/3/model.sdf]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/backpack/3/thumbnails/1.png]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/backpack/3/thumbnails/2.png]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/backpack/3/thumbnails/3.png]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/backpack/3/thumbnails/4.png]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/backpack/3/thumbnails/5.png]
[Dbg] [LocalCache.cc:601] Model [backpack] loading resource from another model, named [Backpack]. On Blueprint (ign-fuel-tools 3) and Citadel (ign-fuel-tools 4), [Backpack] is ignored. From Dome (ign-fuel-tools 5), [backpack] will be used. If [Backpack] is not a model belonging to owner [openrobotics], fix your SDF file!
[Dbg] [LocalCache.cc:601] Model [backpack] loading resource from another model, named [Backpack]. On Blueprint (ign-fuel-tools 3) and Citadel (ign-fuel-tools 4), [Backpack] is ignored. From Dome (ign-fuel-tools 5), [backpack] will be used. If [Backpack] is not a model belonging to owner [openrobotics], fix your SDF file!
[Msg] Downloading model [https://fuel.gazebosim.org/openrobotics/models/gazebo - relative paths]
[Dbg] [FuelClient.cc:2002] Downloading from a referral link [https://gz-fuel-resources-production.s3.amazonaws.com/OpenRobotics/9f31aac6-c10b-48ec-945e-ae2be34d28d4/.zips/2.zip?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAS5OHIRKDBY6VUUFF%2F20240429%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20240429T140812Z&X-Amz-Expires=3600&X-Amz-SignedHeaders=host&X-Amz-Signature=85def186894bfc8ec4fbb82b79481c93552f7ca7b15501308213d722b5af93be]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/gazebo - relative paths/2/materials/textures/gazebo_diffuse.jpg]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/gazebo - relative paths/2/materials/textures/gazebo_spec.jpg]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/gazebo - relative paths/2/meshes/gazebo.dae]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/gazebo - relative paths/2/model.config]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/gazebo - relative paths/2/model.sdf]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/gazebo - relative paths/2/thumbnails/1.png]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/gazebo - relative paths/2/thumbnails/2.png]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/gazebo - relative paths/2/thumbnails/3.png]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/gazebo - relative paths/2/thumbnails/4.png]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/gazebo - relative paths/2/thumbnails/5.png]
[Msg] Downloading model [https://fuel.gazebosim.org/openrobotics/models/actor - relative paths]
[Dbg] [FuelClient.cc:2002] Downloading from a referral link [https://gz-fuel-resources-production.s3.amazonaws.com/OpenRobotics/c2fa772d-06f2-4a72-b07f-33fa355d875d/.zips/2.zip?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAS5OHIRKDBY6VUUFF%2F20240429%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20240429T140815Z&X-Amz-Expires=3600&X-Amz-SignedHeaders=host&X-Amz-Signature=cdb5f33134ce5b2c735dcdda386cb0c29c7837f76b0b6885b66a554f266f7bdd]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/actor - relative paths/2/meshes/gesture.bvh]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/actor - relative paths/2/meshes/moonwalk.dae]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/actor - relative paths/2/meshes/run.dae]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/actor - relative paths/2/meshes/sit.dae]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/actor - relative paths/2/meshes/sit_down.dae]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/actor - relative paths/2/meshes/sitting.dae]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/actor - relative paths/2/meshes/stand.dae]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/actor - relative paths/2/meshes/stand_up.dae]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/actor - relative paths/2/meshes/talk_a.dae]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/actor - relative paths/2/meshes/talk_b.dae]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/actor - relative paths/2/meshes/walk.dae]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/actor - relative paths/2/model.config]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/actor - relative paths/2/model.sdf]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/actor - relative paths/2/thumbnails/1.png]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/actor - relative paths/2/thumbnails/2.png]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/actor - relative paths/2/thumbnails/3.png]
[Msg] Serving entity system service on [/entity/system/add]
[Dbg] [Physics.cc:804] Loaded [ignition::physics::dartsim::Plugin] from library [/usr/lib/x86_64-linux-gnu/ign-physics-5/engine-plugins/libignition-physics-dartsim-plugin.so]
[Dbg] [SystemManager.cc:70] Loaded system [gz::sim::systems::Physics] for entity [1]
[Msg] Create service on [/world/shapes/create]
[Msg] Remove service on [/world/shapes/remove]
[Msg] Pose service on [/world/shapes/set_pose]
[Msg] Pose service on [/world/shapes/set_pose_vector]
[Msg] Light configuration service on [/world/shapes/light_config]
[Msg] Physics service on [/world/shapes/set_physics]
[Msg] SphericalCoordinates service on [/world/shapes/set_spherical_coordinates]
[Msg] Enable collision service on [/world/shapes/enable_collision]
[Msg] Disable collision service on [/world/shapes/disable_collision]
[Msg] Material service on [/world/shapes/visual_config]
[Msg] Material service on [/world/shapes/wheel_slip]
[Dbg] [SystemManager.cc:70] Loaded system [gz::sim::systems::UserCommands] for entity [1]
[Dbg] [SystemManager.cc:70] Loaded system [gz::sim::systems::SceneBroadcaster] for entity [1]
[Msg] Loaded level [3]
[Msg] Serving world controls on [/world/shapes/control], [/world/shapes/control/state] and [/world/shapes/playback/control]
[Msg] Serving GUI information on [/world/shapes/gui/info]
[Msg] World [shapes] initialized with [default_physics] physics profile.
[Msg] Serving world SDF generation service on [/world/shapes/generate_world_sdf]
[Msg] Serving world names on [/gazebo/worlds]
[Msg] Resource path add service on [/gazebo/resource_paths/add].
[Msg] Resource path get service on [/gazebo/resource_paths/get].
[Msg] Resource path resolve service on [/gazebo/resource_paths/resolve].
[Msg] Resource paths published on [/gazebo/resource_paths].
[Msg] Server control service on [/server_control].
[Msg] Found no publishers on /stats, adding root stats topic
[Msg] Found no publishers on /clock, adding root clock topic
[Dbg] [SimulationRunner.cc:496] Creating PostUpdate worker threads: 2
[Dbg] [SimulationRunner.cc:507] Creating postupdate worker thread (0)
[Msg] Downloading model [https://fuel.gazebosim.org/openrobotics/models/radio]
[Dbg] [FuelClient.cc:2002] Downloading from a referral link [https://gz-fuel-resources-production.s3.amazonaws.com/OpenRobotics/00c6ae65-99d4-4605-90d4-4426b401222c/.zips/4.zip?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAS5OHIRKDBY6VUUFF%2F20240429%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20240429T140818Z&X-Amz-Expires=3600&X-Amz-SignedHeaders=host&X-Amz-Signature=fd6baf99fd05a9e037f472069dc95f9d72d882f0d990e1bf368c0e7a3fea5c79]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/radio/4/materials/textures/Radio.png]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/radio/4/materials/textures/Radio_Emmisive.png]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/radio/4/meshes/Radio.dae]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/radio/4/model.config]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/radio/4/model.sdf]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/radio/4/thumbnails/1.png]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/radio/4/thumbnails/2.png]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/radio/4/thumbnails/3.png]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/radio/4/thumbnails/4.png]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.gazebosim.org/openrobotics/models/radio/4/thumbnails/5.png]
[Dbg] [LocalCache.cc:601] Model [radio] loading resource from another model, named [Radio]. On Blueprint (ign-fuel-tools 3) and Citadel (ign-fuel-tools 4), [Radio] is ignored. From Dome (ign-fuel-tools 5), [radio] will be used. If [Radio] is not a model belonging to owner [openrobotics], fix your SDF file!
[Dbg] [LocalCache.cc:601] Model [radio] loading resource from another model, named [Radio]. On Blueprint (ign-fuel-tools 3) and Citadel (ign-fuel-tools 4), [Radio] is ignored. From Dome (ign-fuel-tools 5), [radio] will be used. If [Radio] is not a model belonging to owner [openrobotics], fix your SDF file!
[Wrn] [ColladaLoader.cc:1894] emission texture not supported
[Wrn] [FuelClient.cc:1978] The fuel.ignitionrobotics.org URL is deprecrated. Pleasse change https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/Fortress heightmap/tip/files/materials/textures/fortress_heightmap.png to https://fuel.gazebosim.org/1.0/OpenRobotics/models/Fortress heightmap/tip/files/materials/textures/fortress_heightmap.png
[Wrn] [FuelClient.cc:1978] The fuel.ignitionrobotics.org URL is deprecrated. Pleasse change https://fuel.ignitionrobotics.org/1.0/OpenRobotics/models/Fortress heightmap/tip/files/materials/textures/fortress_heightmap.png to https://fuel.gazebosim.org/1.0/OpenRobotics/models/Fortress heightmap/tip/files/materials/textures/fortress_heightmap.png
[Wrn] [FuelClient.cc:1978] The fuel.ignitionrobotics.org URL is deprecrated. Pleasse change https://fuel.ignitionrobotics.org to https://fuel.gazebosim.org
[Msg] Downloading model [https://fuel.ignitionrobotics.org/openrobotics/models/fortress heightmap]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.ignitionrobotics.org/openrobotics/models/fortress heightmap/2/materials/textures/dirt_diffusespecular.png]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.ignitionrobotics.org/openrobotics/models/fortress heightmap/2/materials/textures/flat_normal.png]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.ignitionrobotics.org/openrobotics/models/fortress heightmap/2/materials/textures/fortress_heightmap.png]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.ignitionrobotics.org/openrobotics/models/fortress heightmap/2/materials/textures/fungus_diffusespecular.png]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.ignitionrobotics.org/openrobotics/models/fortress heightmap/2/materials/textures/grass_diffusespecular.png]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.ignitionrobotics.org/openrobotics/models/fortress heightmap/2/model.config]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.ignitionrobotics.org/openrobotics/models/fortress heightmap/2/model.sdf]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.ignitionrobotics.org/openrobotics/models/fortress heightmap/2/thumbnails/0.png]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.ignitionrobotics.org/openrobotics/models/fortress heightmap/2/thumbnails/1.png]
[Dbg] [Zip.cc:180] Created file [/root/.ignition/fuel/fuel.ignitionrobotics.org/openrobotics/models/fortress heightmap/2/thumbnails/2.png]
Dbg ODE Heightfield AABB: min = {-128, -128, -0.05} max = {128, 128, 49.6078}
[Msg] Serving scene information on [/world/shapes/scene/info]
[Msg] Serving graph information on [/world/shapes/scene/graph]
[Msg] Serving full state on [/world/shapes/state]
[Msg] Serving full state (async) on [/world/shapes/state_async]
[Msg] Publishing scene information on [/world/shapes/scene/info]
[Msg] Publishing entity deletions on [/world/shapes/scene/deletion]
[Msg] Publishing state changes on [/world/shapes/state]
[Msg] Publishing pose messages on [/world/shapes/pose/info]
[Msg] Publishing dynamic pose messages on [/world/shapes/dynamic_pose/info]

Logs from gazebo launch

[Dbg] [Manager.cc:1137] Loading plugin. Name[ignition::launch::WebsocketServer] File[ignition-launch-websocket-server]
[Dbg] [WebsocketServer.cc:403] Using port[9002]
[Wrn] [WebsocketServer.cc:548] Partial SSL configuration specified. Please specify:     <ssl>
          <cert_file>PATH_TO_CERT_FILE</cert_file>
          <private_key_file>PATH_TO_KEY_FILE</private_key_file>
        </ssl>.
Continuing without SSL.
[Err] [WebsocketServer.cc:565] Unable to create websocket server

[azeey]

@nkoenig Can you help triage this?

[nkoenig]

I ran Fortress on Jammy, and was unable to reproduce this.

My versions:

• ign-gazebo version 6.16.0
• ign-launch version 5.3.0
• OS Ubuntu 24.04

I was able to reproduce the error if an existing instance of ign launch websocket.ign was active. Maybe there was a zombie process on your system? I've noticed that ign launch takes almost 30 seconds to die after a ctrl-c.

[varunpandey0502]

Hi all, updating here regarding the Gazebo WebSocket server issue:

Issue:
We were seeing a generic "Unable to create websocket server" error in multiple Gazebo versions (tried Ignition Fortress, Garden, and Harmonic) on Ubuntu 22.04.

Debug Steps:

• Replicated on several Gazebo builds, all with same error.
• Made a minimal libwebsockets test to isolate the problem.
• Identified root error: OOM allocating 1073741816 fds (trying to allocate 1 billion file descriptors!).

Root Cause:

• Gazebo’s WebSocket server code wasn’t setting the fd_limit_per_thread parameter.
• On Ubuntu 22.04, libwebsockets 4.0.20 allocates 1B FDs by default if this parameter is missing.
• But in Ubuntu 24.04 (libwebsockets 4.3.3), it fails gracefully without trying to allocate a huge number of FDs.
• Possible related issue?

How I Fixed It:

• Switched the base image to Ubuntu 24.04 (Noble), which provides libwebsockets 4.3.3 out of the box.
• No changes needed in Gazebo source code.

Result:

• WebSocket server starts up without issues.
• Port 9002 is open/listening.
• gzweb client successfully connects and renders the 3D scene.
• Verified using shapes.sdf world.