Docker proxy for MySQL: "Lost connection" message from host machine - mysql

Question

What I want
There is the https://github.com/jwilder/nginx-proxy package. This is very useful for "HTTP", but I want to use it to TCP too. (MySQL)
Here are my changes: https://github.com/fchris82/nginx-proxy/commit/33d80ea4d4be5d511e4dab0413d516770aa15262
As you can see, I have added stream {} block to nginx.conf and the /etc/nginx/stream.conf.d directory. Here is the generated default.conf for stream block:
access_log off;
error_log /var/log/nginx/debug.log debug;
resolver 127.0.0.11;
# whoami.loc
upstream whoami.loc {
## Can be connect with "nginxproxy_default" network
# nginxproxy_mysql_1
server 192.168.32.2:3306;
}
server {
listen whoami.loc:81;
proxy_pass whoami.loc;
}
What I did, how can you reproduce the error
# Set host
> sudo echo "127.0.0.1 whoami.loc" >> /etc/hosts
# Start containers
> docker-compose up -d
# "Login" the proxy container
> docker-compose exec nginx-proxy /bin/bash
# Test connect to MySQL from proxy container
root> mysql -u root -proot -h whoami.loc -P 81
# --> OK, it works! Let's exit.
mariadb> \q
# Exit from container
root> exit
# Check host
> ping whoami.loc
# --> OK, 127.0.0.1
# Check docker ports
> docker-compose ps
Name Command State Ports
-----------------------------------------------------------------------------------------------------------
nginxproxy_mysql_1 docker-entrypoint.sh mysqld Up 3306/tcp
nginxproxy_nginx-proxy_1 /app/docker-entrypoint.sh ... Up 0.0.0.0:180->80/tcp, 0.0.0.0:81->81/tcp
nginxproxy_whoami_1 /app/http Up 8000/tcp
# --> OK
# Try to direct connection from host (You can read the IP from the /etc/nginx/stream.conf.d/default.conf file)
> mysql -u root -proot -h 192.168.32.2
# --> OK, exit
mysql> \q
# Try to connect from host with "domain" through docker proxy
> mysql -u root -proot -H whoami.loc -P 81 --protocol=tcp
# ERROR 2013 (HY000): Lost connection to MySQL server at 'reading initial communication packet', system error: 2
So, has anybody idea why works from container but why doesn't work from host?
The "solution"
There isn't solution for what I realy wanted. I wanted something like this: Nginx TCP forwarding based on hostname . Tarun's answer solved the error message, thank you.

Answer 1

You need to make sure that
server {
listen whoami.loc:81;
proxy_pass whoami.loc;
}
I getting generated as
server {
listen 81;
proxy_pass whoami.loc;
}
Because for your original config to work, it needs a host entry in /etc/hosts for whoami.loc. And if you make the host entry as 127.0.0.1 then it will only listen to localhost inside the container. And the connections from outside won't be answered.
That is the reason after making the host entry and restart nginx, it worked from inside the container but not from the host. Because it became a effect listen as 127.0.0.1:81