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docker ps shows wrong port when disconnecting and reconnecting a container.

Open ArnoSen opened this issue 3 months ago • 3 comments

Description

I am observing strange behavior in the following situation:

  • create a network
  • run 2 containers n1 and n2 in that network
  • disconnect n2
  • disconnect n1
  • reconnect n2
  • when checking connectivity, connectivity to n2 is not restored but to n1 it is restored.

Reproduce

  1. Create a network with default options
$ docker network create test
6ee2fc93a499e22342ede7b2c693ee4e9af123fc24f4e13c8e19e2ba6dcb8ebf
  1. Start 2 containers connected to that network
$ docker run --rm -d -p 80 --name n1 --network test nginx
2ec11c9aeb10b23dab10d89df3b829d975204f126084b69eed88f6372baf9148
$ docker run --rm -d -p 80 --name n2 --network test nginx
f4099db850f6e35fa1b411812db92d2536ec56f8ba0975eeb1bf4c4d61bb7b09
$ docker ps
CONTAINER ID   IMAGE     COMMAND                  CREATED          STATUS          PORTS                                       NAMES
f4099db850f6   nginx     "/docker-entrypoint.…"   23 seconds ago   Up 23 seconds   0.0.0.0:52193->80/tcp, [::]:52193->80/tcp   n2
2ec11c9aeb10   nginx     "/docker-entrypoint.…"   28 seconds ago   Up 28 seconds   0.0.0.0:52191->80/tcp, [::]:52191->80/tcp   n1
  1. Check connectivity
$ curl localhost:52193
<!DOCTYPE html>
<html> (...)
$ curl localhost:52191
<!DOCTYPE html>
<html>

  1. Disconnect the 2nd container from the network $ docker network disconnect test n2

  2. Verify connectivity

$ curl localhost:52193
^C // dead as expected
$ curl localhost:52191
<!DOCTYPE html>
<html>
(...)  // alive as expected
  1. Disconnect n1 and verify connectivity
$ docker network disconnect test n1
$ curl localhost:52193
curl: (56) Recv failure: Connection reset by peer // as expected
$ curl localhost:52191
curl: (56) Recv failure: Connection reset by peer // as expected
  1. (Re)connect n2
$ docker network connect test n2
$ docker network inspect test
[
    {
        "Name": "test",
        "Id": "6ee2fc93a499e22342ede7b2c693ee4e9af123fc24f4e13c8e19e2ba6dcb8ebf",
        "Created": "2025-10-27T13:47:32.852200342Z",
        "Scope": "local",
        "Driver": "bridge",
        "EnableIPv4": true,
        "EnableIPv6": false,
        "IPAM": {
            "Driver": "default",
            "Options": {},
            "Config": [
                {
                    "Subnet": "172.16.1.0/24",
                    "Gateway": "172.16.1.1"
                }
            ]
        },
        "Internal": false,
        "Attachable": false,
        "Ingress": false,
        "ConfigFrom": {
            "Network": ""
        },
        "ConfigOnly": false,
        "Containers": {
            "f4099db850f6e35fa1b411812db92d2536ec56f8ba0975eeb1bf4c4d61bb7b09": {
                "Name": "n2",
                "EndpointID": "a2c2b1e4d0dea3c5dd04d5d343c498508f59e0b2ec7954b1ea5bdc073ba02a8a",
                "MacAddress": "86:ff:4c:de:63:4d",
                "IPv4Address": "172.16.1.2/24",
                "IPv6Address": ""
            }
        },
        "Options": {
            "com.docker.network.enable_ipv4": "true",
            "com.docker.network.enable_ipv6": "false"
        },
        "Labels": {}
    }
]

It says that network n2 is connected.

  1. Check connectivity via curl
$ curl localhost:52193
curl: (56) Recv failure: Connection reset by peer
// Wait, what?? Port 52193 is associated with n2 that was reconnected.
$ curl localhost:52191
<!DOCTYPE html>
<html> (...)
// Now, wait again.... n1 is now connected although we did not change its state?

Expected behavior

I was expecting a result for this command: $ curl localhost:52193

(...)

and a connection error for this command: $ curl localhost:52191 curl: (56) Recv failure: Connection reset by peer

docker version

% docker version
Client:
 Version:           28.5.1
 API version:       1.51
 Go version:        go1.24.8
 Git commit:        e180ab8
 Built:             Wed Oct  8 12:16:17 2025
 OS/Arch:           darwin/arm64
 Context:           desktop-linux

Server: Docker Desktop 4.49.0 (208700)
 Engine:
  Version:          28.5.1
  API version:      1.51 (minimum version 1.24)
  Go version:       go1.24.8
  Git commit:       f8215cc
  Built:            Wed Oct  8 12:18:25 2025
  OS/Arch:          linux/arm64
  Experimental:     false
 containerd:
  Version:          1.7.27
  GitCommit:        05044ec0a9a75232cad458027ca83437aae3f4da
 runc:
  Version:          1.2.5
  GitCommit:        v1.2.5-0-g59923ef
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

docker info

% docker info
Client:
 Version:    28.5.1
 Context:    desktop-linux
 Debug Mode: false
 Plugins:
  ai: Docker AI Agent - Ask Gordon (Docker Inc.)
    Version:  v1.9.11
    Path:     /Users/rr26ua/.docker/cli-plugins/docker-ai
  buildx: Docker Buildx (Docker Inc.)
    Version:  v0.29.1-desktop.1
    Path:     /Users/rr26ua/.docker/cli-plugins/docker-buildx
  compose: Docker Compose (Docker Inc.)
    Version:  v2.40.2-desktop.1
    Path:     /Users/rr26ua/.docker/cli-plugins/docker-compose
  debug: Get a shell into any image or container (Docker Inc.)
    Version:  0.0.45
    Path:     /Users/rr26ua/.docker/cli-plugins/docker-debug
  desktop: Docker Desktop commands (Docker Inc.)
    Version:  v0.2.0
    Path:     /Users/rr26ua/.docker/cli-plugins/docker-desktop
  extension: Manages Docker extensions (Docker Inc.)
    Version:  v0.2.31
    Path:     /Users/rr26ua/.docker/cli-plugins/docker-extension
  init: Creates Docker-related starter files for your project (Docker Inc.)
    Version:  v1.4.0
    Path:     /Users/rr26ua/.docker/cli-plugins/docker-init
  mcp: Docker MCP Plugin (Docker Inc.)
    Version:  v0.24.0
    Path:     /Users/rr26ua/.docker/cli-plugins/docker-mcp
  model: Docker Model Runner (Docker Inc.)
    Version:  v0.1.45
    Path:     /Users/rr26ua/.docker/cli-plugins/docker-model
  offload: Docker Offload (Docker Inc.)
    Version:  v0.5.1
    Path:     /Users/rr26ua/.docker/cli-plugins/docker-offload
  sandbox: Docker Sandbox (Docker Inc.)
    Version:  v0.3.1
    Path:     /Users/rr26ua/.docker/cli-plugins/docker-sandbox
  sbom: View the packaged-based Software Bill Of Materials (SBOM) for an image (Anchore Inc.)
    Version:  0.6.0
    Path:     /Users/rr26ua/.docker/cli-plugins/docker-sbom
  scout: Docker Scout (Docker Inc.)
    Version:  v1.18.3
    Path:     /Users/rr26ua/.docker/cli-plugins/docker-scout

Server:
 Containers: 0
  Running: 0
  Paused: 0
  Stopped: 0
 Images: 42
 Server Version: 28.5.1
 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
 CDI spec directories:
  /etc/cdi
  /var/run/cdi
 Discovered Devices:
  cdi: docker.com/gpu=webgpu
 Swarm: inactive
 Runtimes: io.containerd.runc.v2 runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: 05044ec0a9a75232cad458027ca83437aae3f4da
 runc version: v1.2.5-0-g59923ef
 init version: de40ad0
 Security Options:
  seccomp
   Profile: builtin
  cgroupns
 Kernel Version: 6.10.14-linuxkit
 Operating System: Docker Desktop
 OSType: linux
 Architecture: aarch64
 CPUs: 12
 Total Memory: 17.54GiB
 Name: docker-desktop
 ID: 16f9601d-bfa4-451a-b70a-dee4df4530e5
 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/rr26ua/Library/Containers/com.docker.docker/Data/docker-cli.sock
 Experimental: false
 Insecure Registries:
  hubproxy.docker.internal:5555
  ::1/128
  127.0.0.0/8
 Live Restore Enabled: false
 Default Address Pools:
   Base: 172.16.0.0/12, Size: 24

Diagnostics ID

2FE4CEFD-2D82-4B13-AE58-4D612D05FC79/20251027135322

Additional Info

No response

ArnoSen avatar Oct 27 '25 13:10 ArnoSen