Docker/Docker-compose error starting userland proxy

Question

I'm getting an error bringing up a project:

$ docker-compose -f docker-compose.yml up -d
Starting project-container-a ... 
Starting project-container-a
Recreating project-container-b ... 
Recreating project-container-b
Starting project-container-c ... 
Starting project-container-c ... error

ERROR: for project-container-c  Cannot start service project-container-c: driver failed programming external connectivity on endpoint project-container-c (123abcStarting project-container-a ... done

ERROR: for project-container-c  Cannot start service project-container-c: driver failed programming external connectivity on endpoint project-container-c (123abc673b494c1505): Error starting userland proxy: 
ERROR: Encountered errors while bringing up the project.

The docker-compose file defines project-container-c as:

services:
    bento-legacy-nginx:
        image: project-container-c
        container_name: project-container-c

        build:
            context: ./
            cache_from:
              - project-container-c
            dockerfile: ./build/nginx/Dockerfile

        ports:
            - 80:80

        restart: always

        volumes:
            - ./app:/var/www/app

Nothing is bound to 80:

$ sudo netstat -tulpn
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name    
tcp        0      0 127.0.0.53:53           0.0.0.0:*               LISTEN      7665/systemd-resolv 
tcp        0      0 127.0.0.1:631           0.0.0.0:*               LISTEN      1089/cupsd          
tcp6       0      0 :::9000                 :::*                    LISTEN      1815/java           
tcp6       0      0 :::3308                 :::*                    LISTEN      32040/rootlesskit   
tcp6       0      0 127.0.0.1:63342         :::*                    LISTEN      1815/java           
tcp6       0      0 :::20080                :::*                    LISTEN      1815/java           
tcp6       0      0 ::1:631                 :::*                    LISTEN      1089/cupsd          
tcp6       0      0 :::10137                :::*                    LISTEN      1815/java           
tcp6       0      0 127.0.0.1:6942          :::*                    LISTEN      1815/java           
udp        0      0 127.0.0.53:53           0.0.0.0:*                           7665/systemd-resolv 
udp        0      0 0.0.0.0:68              0.0.0.0:*                           1753/dhclient       
udp        0      0 0.0.0.0:631             0.0.0.0:*                           1138/cups-browsed   
udp        0      0 0.0.0.0:53353           0.0.0.0:*                           1094/avahi-daemon:  
udp        0      0 0.0.0.0:5353            0.0.0.0:*                           1094/avahi-daemon:  
udp6       0      0 :::60252                :::*                                1094/avahi-daemon:  
udp6       0      0 :::5353                 :::*                                1094/avahi-daemon:  

I am (attempting) to run Docker in rootless mode :

$ ps -aux | grep -i docker
me       6378  0.0  0.0  14428   960 pts/2    S+   00:11   0:00 grep --color=auto -i docker
me      32040  0.0  0.0 111788  7328 ?        Ssl  Mar10   0:00 rootlesskit --net=vpnkit --mtu=1500 --slirp4netns-sandbox=auto --slirp4netns-seccomp=auto --disable-host-loopback --port-driver=builtin --copy-up=/etc --copy-up=/run /home/me/bin/dockerd-rootless.sh --experimental --storage-driver=overlay2
me      32049  0.0  0.0 110124  7128 ?        Sl   Mar10   0:00 /proc/self/exe --net=vpnkit --mtu=1500 --slirp4netns-sandbox=auto --slirp4netns-seccomp=auto --disable-host-loopback --port-driver=builtin --copy-up=/etc --copy-up=/run /home/me/bin/dockerd-rootless.sh --experimental --storage-driver=overlay2
me      32084  0.6  0.3 903356 63564 ?        Sl   Mar10   0:06 dockerd --experimental --storage-driver=overlay2
me      32098  0.4  0.1 793340 28420 ?        Ssl  Mar10   0:04 containerd --config /run/user/1000/docker/containerd/containerd.toml --log-level info

---

Docker version 19.03.6, build 369ce74a3c, Ubuntu 18.04

What is this error starting userland proxy?

Answer 1

I cannot say for certain, but this appears to be the inability to bind to a privileged port . Having the app bind to 8080 instead of 80 allows the container to boot and run without error