cannot create listening socket [:::2375] after #108

[jscheytt]

Hi there,

we are running docker-socket-proxy in Docker Swarm (docker engine v23). Since the newest nightly build, we get this error on startup:

[WARNING] 340/080535 (1) : config : missing timeouts for backend 'docker-events'.
   | While not properly invalid, you will certainly encounter various problems
   | with such a configuration. To fix this, please ensure that all following
   | timeouts are set to a non-zero value: 'client', 'connect', 'server'.
[WARNING] 340/080535 (1) : Can't open global server state file '/var/lib/haproxy/server-state': No such file or directory
Proxy dockerbackend started.
Proxy docker-events started.
[NOTICE] 340/080535 (1) : haproxy version is 2.2.31-d69335f
[ALERT] 340/080535 (1) : Starting frontend dockerfrontend: cannot create listening socket [:::2375]

This is likely related to #108.

We have not set up any IPv6 configuration in the Docker daemon nor in our networks. Do we need to do that in order for docker-socket-proxy to keep working?

This is roughly how we deploy docker-socket-proxy in Docker Swarm currently:

version: "3.9"
services:
  docker-socket-proxy:
    deploy:
      mode: global
      update_config:
        order: start-first
      resources:
        limits:
          memory: "104857600"
          pids: 1000
        reservations:
          cpus: "0.02"
          memory: "104857600"
      restart_policy:
        condition: on-failure
        max_attempts: 5
      placement:
        constraints:
        - node.role == manager
    environment:
      CONTAINERS: "1"
      NETWORKS: "1"
      NODES: "1"
      POST: "1"
      SERVICES: "1"
      SWARM: "1"
      TASKS: "1"
    healthcheck:
      test:
      - CMD-SHELL
      - wget -O - http://127.0.0.1:2375/_ping
      interval: 5s
      retries: 10
    image: tecnativa/docker-socket-proxy:nightly@sha256:46148a17aad9df1c21e4b7f173b8c0b5efe213ab90b193cec583d5adcaa16965
    logging:
      options:
        tag: '{{.Name}}'
    networks:
      internal: null
    volumes:
    - type: bind
      source: /var/run/docker.sock
      target: /var/run/docker.sock
      read_only: true
networks:
  internal: {}

[pedrobaeza]

Any advice, @saltydk @yajo ?

[saltydk]

We could move the IPv6 bind to an ENV toggle like with the socket capabilities?

[saltydk]

I suppose we could add a second bind

frontend dockerfrontend
    bind :2375
    bind :::2375 v6only

I will do some tests with that.

[saltydk]

@jscheytt Could you try this image?

saltydk/docker-socket-proxy:edge

[jscheytt]

@saltydk Still getting the same error ...

[saltydk]

Wonder why your setup doesn't work. I've tested both the current version and mine on a IPv4 only system.

[saltydk]

Are you just looking for the error or actually testing if the proxy works with the other image?

[jscheytt]

I don't understand your last question. What I did is: I changed the stack I pasted at the top to use the image you pasted. I rolled out this change via docker stack up --prune -c FILENAME STACKNAME. I then checked the logs and they contained the same text again as at the top.

Maybe some more system context helps: Host OS is RHEL v8. Docker daemon config is this:

{
  "metrics-addr": "0.0.0.0:9323",
  "log-driver": "syslog",
  "log-opts": {
    "syslog-address": "*REDACTED*"
  },
  "no-new-privileges": true,
  "userland-proxy": false
}

[saltydk]

I meant actually using the proxy, assuming the container doesn't stop due to the error.

[jscheytt]

The container unfortunately does stop due to the error, so I cannot try using it ...

[saltydk]

@pedrobaeza Not sure how to fix this outside of having the entrypoint toggle the bind based on an ENV like USE_IPV6 or the like since haproxy seems unable to handle it internally.

[yajo]

Have you tried this?

frontend dockerfrontend
    bind [::]:2375 v4v6

Docs: https://www.haproxy.com/documentation/haproxy-configuration-tutorials/core-concepts/frontends/#listen-on-multiple-ip-addresses-and-ports

[saltydk]

Have you tried this?

frontend dockerfrontend
    bind [::]:2375 v4v6

Docs: https://www.haproxy.com/documentation/haproxy-configuration-tutorials/core-concepts/frontends/#listen-on-multiple-ip-addresses-and-ports

I've built an image with that although I'd be surprised if it changes anything.

saltydk/docker-socket-proxy:edge

[jscheytt]

Unfortunately still the same error ...

[yajo]

Then it'll have to be based on an option, or we'll have to roll back the ipv6 support.