Nginx upstream doesn't work with docker deploy stack - docker

Question

I'm trying to deploy a stack with docker.
Here is how my stack works:
nginx-proxy (redirect user requests to the good container)
website (simple nginx serving a website)
api (django application, launch with gunicorn)
nginx-api (serving static files and uploaded files and redirect to the API container if it is an endpoint)
This is my docker-compose.yml:
version: '3.2'
services:
website:
container_name: nyl2pronos-website
image: nyl2pronos-website
restart: always
build:
context: nyl2pronos_webapp
dockerfile: Dockerfile
volumes:
- ./logs/nginx-website:/var/log/nginx
expose:
- "80"
deploy:
replicas: 10
update_config:
parallelism: 5
delay: 10s
api:
container_name: nyl2pronos-api
build:
context: nyl2pronos_api
dockerfile: Dockerfile
image: nyl2pronos-api
restart: always
ports:
- 8001:80
expose:
- "80"
depends_on:
- db
- memcached
environment:
- DJANGO_PRODUCTION=1
volumes:
- ./data/api/uploads:/code/uploads
- ./data/api/static:/code/static
nginx-api:
image: nginx:latest
container_name: nyl2pronos-nginx-api
restart: always
expose:
- "80"
volumes:
- ./data/api/uploads:/uploads
- ./data/api/static:/static
- ./nyl2pronos_api/config:/etc/nginx/conf.d
- ./logs/nginx-api:/var/log/nginx
depends_on:
- api
nginx-proxy:
image: nginx:latest
container_name: nyl2pronos-proxy
restart: always
ports:
- 80:80
- 443:443
volumes:
- ./proxy:/etc/nginx/conf.d
- /etc/letsencrypt:/etc/letsencrypt
- ./logs/nginx-proxy:/var/log/nginx
deploy:
placement:
constraints: [node.role == manager]
depends_on:
- nginx-api
- website
When I use docker-compose up everything works fine.
But when I try to deploy with docker stack deploy --compose-file=docker-compose.yml prod. My nginx config files can't find the different upstreams.
This is the error provided by my service nginx-api:
2019/03/23 17:32:41 [emerg] 1#1: host not found in upstream "api" in /etc/nginx/conf.d/nginx.conf:2
See below my nginx.conf:
upstream docker-api {
server api;
}
server {
listen 80;
server_name xxxxxxxxxxxxxx;
location /static {
autoindex on;
alias /static/;
}
location /uploads {
autoindex on;
alias /uploads/;
}
location / {
proxy_pass http://docker-api;
proxy_redirect off;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Host $server_name;
}
}
If you see something wrong in my configuration or something I can do better, let me know!

Answer 1

this is happening because nginx-api service is up before the api service.
but i added the depends_on option?
you are right, and this option should work for a docker-compose up case.
but unfortunately not on docker stack deploy, or, as the docs put it:
The depends_on option is ignored when deploying a stack in swarm mode
with a version 3 Compose file.
ok, so what can i do now?
nothing. its actually not a bug-
docker swarm nodes (your stack services) are supposed to recover automatically on error. (thats why you define the restart: always option). so it should work for you anyway.
if you are using the compose file only for deploying the stack and not on a docker-compose up - you may remove the depends_on option completely, it means nothing to docker stack.