CODEWITHSUNDEEP
nginxdocker
Jordi
Jordi

Reputation: 23277

nginx docker container: 502 bad gateway response

I've a service listening to 8080 port. This one is not a container.

Then, I've created a nginx container using official image:

docker run --name nginx -d -v /root/nginx/conf:/etc/nginx/conf.d -p 443:443 -p 80:80 nginx

After all:

# netstat -tupln | grep 443
tcp6       0      0 :::443                  :::*                    LISTEN      3482/docker-proxy
# netstat -tupln | grep 80
tcp6       0      0 :::80                   :::*                    LISTEN      3489/docker-proxy
tcp6       0      0 :::8080                 :::*                    LISTEN      1009/java

Nginx configuration is:

upstream eighty {
    server 127.0.0.1:8080;
}

server {
    listen 80;
    server_name eighty.domain.com;

    location / {
      proxy_pass                        http://eighty;
    }
}

I've checked I'm able to connect with with this server with # curl http://127.0.0.1:8080

 <html><head><meta http-equiv='refresh'
 content='1;url=/login?from=%2F'/><script>window.location.replace('/login?from=%2F');</script></head><body
 style='background-color:white; color:white;'>
 ...

It seems running well, however, when I'm trying to access using my browser, nginx tells bt a 502 bad gateway response.

I'm figuring out it can be a problem related with the visibility between a open by a non-containerized process and a container. Can I container stablish connection to a port open by other non-container process?

EDIT

Logs where upstream { server 127.0.0.1:8080; }:

2016/07/13 09:06:53 [error] 5#5: *1 connect() failed (111: Connection refused) while connecting to upstream, client: 62.57.217.25, server: eighty.domain.com, request: "GET / HTTP/1.1", upstream: "http://127.0.0.1:8080/", host: "eighty.domain.com"
62.57.217.25 - - [13/Jul/2016:09:06:53 +0000] "GET / HTTP/1.1" 502 173 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64; rv:47.0) Gecko/20100101 Firefox/47.0" "-"

Logs where upstream { server 0.0.0.0:8080; }:

62.57.217.25 - - [13/Jul/2016:09:00:30 +0000] "GET / HTTP/1.1" 502 173 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64; rv:47.0) Gecko/20100101 Firefox/47.0" "-" 2016/07/13 09:00:30 [error] 5#5: *1 connect() failed (111: Connection refused) while connecting to upstream, client:
62.57.217.25, server: eighty.domain.com, request: "GET / HTTP/1.1", upstream: "http://0.0.0.0:8080/", host: "eighty.domain.com" 2016/07/13 09:00:32 [error] 5#5: *3 connect() failed (111: Connection refused) while connecting to upstream, client: 62.57.217.25, server: eighty.domain.com, request: "GET / HTTP/1.1", upstream: "http://0.0.0.0:8080/", host: "eighty.domain.com"
62.57.217.25 - - [13/Jul/2016:09:00:32 +0000] "GET / HTTP/1.1" 502 173 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64; rv:47.0) Gecko/20100101 Firefox/47.0" "-"

Any ideas?

Upvotes: 91

Views: 234316

Answers (9)

MaximilianKohler
MaximilianKohler

Reputation: 53

I've checked I'm able to connect with with this server with # curl http://127.0.0.1:8080

In my case I would get a curl: (56) Recv failure: Connection reset by peer error when doing that, and it turned out to be a firewall issue. I disabled the firewall and it worked.

I got a clue by curling the docker IP, which properly output the html homepage.

sudo ip addr show docker0
4: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default
    link/ether 02:42:a9:60:8e:f4 brd ff:ff:ff:ff:ff:ff
    inet 172.17.0.1/16 brd 172.17.255.255 scope global docker0
       valid_lft forever preferred_lft forever

curl 172.17.0.1:5870

Before disabling firewall:

curl 127.0.0.1:5870
curl: (56) Recv failure: Connection reset by peer

curl 0.0.0.0:5870
curl: (56) Recv failure: Connection reset by peer

After: I get the HTML page output.

Upvotes: 0

Azizou Ogbone
Azizou Ogbone

Reputation: 11

I was getting the same error, but in my case it is because I was directing https traffic (from the load balancer - ALB) to http. Changing the protocol of the target group to http resolved it.

Upvotes: 0

Moj
Moj

Reputation: 378

Just to complete other answers, I'm using mac for development and using host.docker.internal directly on upstream worked for me and no need to pass the host remote IP address. Here is config of the proxy nginx:

events { worker_connections 1024; }

http {
    upstream app1 {
        server host.docker.internal:81;
    }

    upstream app1 {
        server host.docker.internal:82;
    }
    
    server {
        listen 80;
        server_name app1.com;
    
        location / {
          proxy_pass    http://app1;
        }
    }

    server {
        listen 80;
        server_name app2.com;
    
        location / {
          proxy_pass    http://app2;
        }
    }
}

As you can see, I used different ports for different apps behind the nginx proxy. I used port 81 for the app1 and port 82 for the app2 and both app1 and app2 have their own nginx containers:

For app1:

docker run --name nginx -d -p 81:80 nginx

For app2:

docker run --name nginx -d -p 82:80 nginx

Also, please refer to this link for more details: docker doc for mac

Upvotes: 13

Aanish Amir Waseem
Aanish Amir Waseem

Reputation: 311

# the upstream component nginx needs to connect to
upstream django {

    # server unix:///path/to/your/mysite/mysite.sock; # for a file socket

    server 127.0.0.1:8001; # for a web port socket (we'll use this first)
}


location / {

        uwsgi_pass  django;
        include     /path/to/your/mysite/uwsgi_params; # the uwsgi_params file you installed
    }

complete reference: https://uwsgi-docs.readthedocs.io/en/latest/tutorials/Django_and_nginx.html

Upvotes: 1

ShrimpPhaser
ShrimpPhaser

Reputation: 3497

The Problem

Localhost is a bit tricky when it comes to containers. Within a docker container, localhost points to the container itself. This means, with an upstream like this:

upstream foo{
  server 127.0.0.1:8080;
}

or

upstream foo{
  server 0.0.0.0:8080;
}

you are telling nginx to pass your request to the local host. But in the context of a docker-container, localhost (and the corresponding ip addresses) are pointing to the container itself:

enter image description here

by addressing 127.0.0.1 you will never reach your host machine, if your container is not on the host network.

Solutions

Host Networking

You can choose to run nginx on the same network as your host:

docker run --name nginx -d -v /root/nginx/conf:/etc/nginx/conf.d --net=host nginx

Note that you do not need to expose any ports in this case.

This works though you lose the benefit of docker networking. If you have multiple containers that should communicate through the docker network, this approach can be a problem. If you just want to deploy nginx with docker and do not want to use any advanced docker network features, this approach is fine.

Access the hosts remote IP Address

Another approach is to reconfigure your nginx upstream directive to directly connect to your host machine by adding its remote IP address:

upstream foo{
  //insert your hosts ip here
  server 192.168.99.100:8080;
}

The container will now go through the network stack and resolve your host correctly:

enter image description here

You can also use your DNS name if you have one. Make sure docker knows about your DNS server.

Upvotes: 171

Daniel
Daniel

Reputation: 516

I had this issue and it turned out to be an issue with the docker container not starting up due to a permissions issue.

In my case running 

docker-compose ps

showed that the container had not started and exited with status 1. Turns out the permissions had been lost in migrating to a new machine. Adjusting the permissions to a know staff user on the parent directory fixed the problem for me and I was then able to start docker service where as previously I was getting 

nginx_1_c18a7f6f7d6d | chown: /var/www/html: Operation not permitted

Upvotes: -1

Kamil Witkowski
Kamil Witkowski

Reputation: 2083

What you can do is configure proxy_pass that from container perspective the adress will be pointing to your real host.

To get host address from container perspective you can do as following on Windows with docker 18.03 (or more recent):

Run bash on container from host where image name is nginx (works on Alpine Linux distribution):

 docker run -it nginx /bin/ash

Then run inside container

/ # nslookup host.docker.internal

Name:      host.docker.internal
Address 1: 192.168.65.2

192.168.65.2 is the host's IP - not the bridge IP like in spinus accepted answer.

I am using here host.docker.internal:

The host has a changing IP address (or none if you have no network access). From 18.03 onwards our recommendation is to connect to the special DNS name host.docker.internal, which resolves to the internal IP address used by the host. This is for development purpose and will not work in a production environment outside of Docker for Windows.

Then you can change nginx config to: proxy_pass http://192.168.65.2:{your_app_port};

and it should work fine.

Remember to provide the same port as your local application runs with.

Upvotes: 5

hehe Peng
hehe Peng

Reputation: 11

nginx.sh

ip=$(ifconfig | grep -Eo 'inet (addr:)?([0-9]*\.){3}[0-9]*' | grep -Eo '([0-9]*\.){3}[0-9]*' | grep -v '127.0.0.1' | head -n 1)

docker run --name nginx --add-host="host:${ip}" -p 80:80 -d nginx

nginx.conf

location / {
    ...
    proxy_pass http://host:8080/;
}

It‘s works for me

Upvotes: 1

Андрій Коваль
Андрій Коваль

Reputation: 167

For me helped this line of code proxy_set_header Host $http_host;

server {
   listen            80;
   server_name  localhost;
location / {
   proxy_set_header X-Real-IP $remote_addr;
   proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
   proxy_set_header X-Forwarded-Proto $scheme;
   proxy_set_header Host $http_host;
   proxy_set_header X-NginX-Proxy true;

   proxy_redirect off;
   proxy_pass http://myserver;
}

Upvotes: 12

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