starting nginx docker container with custom nginx config file - docker

Question

My Requirements
I am working on a Windows 10 machine
I have my test app running on http://localhost:3000/
I need to have a reverse proxy setup so http://localhost:80 redirects to http://localhost:3000/ ( i will be adding further rewrite rules when i get the basic setup up and running)
Steps
I am following instructions from
https://www.docker.com/blog/tips-for-deploying-nginx-official-image-with-docker/
I'm trying to create a container (name = mynginx1) specifying my own nginx conf file
$ docker run --name mynginx1 -v C:/zNGINX/testnginx/conf:/etc/nginx:ro -P -d nginx
where "C:/zNGINX/testnginx/conf" contains the file "default.conf" and its contents are
server {
listen 80;
server_name localhost;
location / {
proxy_pass http://localhost:3000;
}
}
A container ID is returned, but "docker ps" does not show it running.
Viewing the container logs using "docker logs mynginx1" shows the following error
2020/03/30 12:27:18 [emerg] 1#1: open() "/etc/nginx/nginx.conf" failed (2: No such file or directory)
nginx: [emerg] open() "/etc/nginx/nginx.conf" failed (2: No such file or directory)
What am I doing wrong?

Answer 1

There were 2 errors in what i was doing
(1) In the conf file, I was using "proxy_pass http://localhost:3000;"
"localhost" in the container is the CONTAINER host, not MY computer. Therefore this needed changing to
proxy_pass http://host.docker.internal:3000;
(2) the path to copy my config file to on the container was not right, i needed to add "conf.d"
docker run --name mynginx1 -v C:/zNGINX/testnginx/conf:/etc/nginx/conf.d:ro -P -d nginx
The documentation I was reading (multiple websites) did not mention adding the "conf.d" directory on the end of the path. However if you view the "/etc/nginx/nginx.conf" file there is a clue on the last line
user nginx;
worker_processes 1;
error_log /var/log/nginx/error.log warn;
pid /var/run/nginx.pid;
events {
worker_connections 1024;
}
http {
include /etc/nginx/mime.types;
default_type application/octet-stream;
log_format main '$remote_addr - $remote_user [$time_local] "$request" '
'$status $body_bytes_sent "$http_referer" '
'"$http_user_agent" "$http_x_forwarded_for"';
access_log /var/log/nginx/access.log main;
sendfile on;
#tcp_nopush on;
keepalive_timeout 65;
#gzip on;
include /etc/nginx/conf.d/*.conf;
}
The "include /etc/nginx/conf.d/*.conf;" indicates that it loads any file ended in ".conf" from the "/etc/nginx/conf.d/" directory.