Docker containers experiencing socket issue (separate Flask + Nginx containers) - nginx

Question

I am experiencing the following error with my multi-container Docker setup after running docker-compose build && docker-compose up and attempting to hit my index page:
[crit] 8#8: *1 connect() to unix:/tmp/uwsgi.sock failed (2: No such file or directory) while connecting to upstream, client: 192.168.99.1, server: localhost, request: "GET / HTTP/1.1", upstream: "uwsgi://unix:/tmp/uwsgi.sock:", host: "192.168.99.100"
Here is my docker-compose.yml:
web:
restart: always
build: ./web-app
expose:
- "8000"
command: /usr/local/bin/uwsgi --ini sample-uwsgi.ini
nginx:
restart: always
build: ./nginx/
ports:
- "80:80"
links:
- web:web
nginx/Dockerfile
FROM nginx
RUN rm /etc/nginx/conf.d/default.conf
ADD sample-nginx.conf /etc/nginx/conf.d/
nginx/sample-nginx.conf
server {
listen 80;
server_name localhost;
charset utf-8;
client_max_body_size 75M;
location / {
include uwsgi_params;
uwsgi_pass unix:/tmp/uwsgi.sock;
}
}
web-app/Dockerfile
FROM ansible/ubuntu14.04-ansible:stable
WORKDIR /root
ADD application.py application.py
ADD requirements.txt requirements.txt
ADD sample-uwsgi.ini sample-uwsgi.ini
ADD ansible /srv/ansible
WORKDIR /srv/ansible
RUN ansible-playbook container-bootstrap.yml -c local
web-app/sample-uswgi.ini
[uwsgi]
module = application
callable = app
master = true
processes = 5
socket = /tmp/uwsgi.sock
chown-socket = www-data:www-data
vacuum = true
enable-threads=True
die-on-term = true
UPDATE
On advice from #kryten I will be using TCP/IP
Updated nginx.conf:
server {
listen 80;
server_name localhost;
charset utf-8;
client_max_body_size 75M;
location / {
uwsgi_pass localhost:8000;
include uwsgi_params;
}
}
Updated uwsgi.ini:
[uwsgi]
module = application
callable = app
master = true
processes = 5
socket = localhost:8000
chown-socket = www-data:www-data
vacuum = true
enable-threads=True
die-on-term = true
and am now pursuing the following error:
[error] 8#8: *1 connect() failed (111: Connection refused) while connecting to upstream, client: 192.168.99.1, server: localhost, request: "GET / HTTP/1.1", upstream: "uwsgi://127.0.0.1:8000", host: "192.168.99.100"

Answer 1

Since web and nginx are separate containers, nginx needs to connect to another computer over TCP. Linking the containers does most of the work already, you just have to point the upstream to web:8000 instead of localhost.

Answer 2

It looks like one of your applications is attempting to connect via a Unix socket instead of over TCP/IP.
This will not work from different containers, because the filesystem in one container (where the socket lives) is not accessible in the other container.
The solution is to reconfigure your application to connect over TCP/IP instead of a Unix socket.
It might be possible to connect by exposing the location in the filesystem where the socket resides to the other container, but I've never tried this & don't know if it would work.