Docker container can't reach another container using hostname

Question

I have 2 containers:

docker run -d -p 9000:9000 --name="my-php" php-fpm:5.4

docker run -d --name="nginx" -p 80:80 -link my-php:web nginx

both are running really fine. Inside the nginx container I can reach the app using

curl http://myapp.dev

and also from host machine as well.

What I'm trying to do is the same curl request but from the my-php container using the same "myapp.dev" hostname, howerver...

curl: (7) Failed to connect to myapp.dev port 80: Connection refused

I can use the container's ip instead, but it doesn't fit me.

Even though I can't reach using curl, I can still ping the other container with no problems.

on nginx container:

root@6252bfe9d545:/# env
WEB_PORT_9000_TCP_PROTO=tcp
HOSTNAME=6252bfe9d545
WEB_PORT_9000_TCP_ADDR=172.17.0.24
WEB_PORT_9000_TCP_PORT=9000
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
PWD=/
NGINX_VERSION=1.7.9-1~wheezy
SHLVL=1
HOME=/root
WEB_NAME=/nginx/web
WEB_PORT_9000_TCP=tcp://172.17.0.24:9000
WEB_PORT=tcp://172.17.0.24:9000
_=/usr/bin/env

root@6252bfe9d545:/# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         172.17.42.1     0.0.0.0         UG    0      0        0 eth0
172.17.0.0      0.0.0.0         255.255.0.0     U     0      0        0 eth0

on php container

root@c7c521c4a40c:/# env
MYSQLDB_PORT_3306_TCP=tcp://172.17.0.22:3306
HOSTNAME=c7c521c4a40c
MYSQLDB_NAME=/php/mysqldb
MEMCACHEDB_ENV_MEMCACHED_VERSION=1.4.22
MYSQLDB_PORT=tcp://172.17.0.22:3306
MEMCACHEDB_PORT=tcp://172.17.0.23:11211
MEMCACHEDB_NAME=/php/memcachedb
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
MYSQLDB_PORT_3306_TCP_PROTO=tcp
MEMCACHEDB_ENV_MEMCACHED_SHA1=5968d357d504a1f52622f9f8a3e85c29558acaa5
PWD=/
MEMCACHEDB_PORT_11211_TCP=tcp://172.17.0.23:11211
MEMCACHEDB_PORT_11211_TCP_PORT=11211
SHLVL=1
HOME=/root
MYSQLDB_PORT_3306_TCP_ADDR=172.17.0.22
MEMCACHEDB_PORT_11211_TCP_PROTO=tcp
MYSQLDB_PORT_3306_TCP_PORT=3306
MEMCACHEDB_PORT_11211_TCP_ADDR=172.17.0.23
_=/usr/bin/env

(here it's showing links to mysql and memchache which I hide on run command before paste on stackoverflow)

ping myapp.dev
PING myapp.dev (127.0.53.53) 56(84) bytes of data.
64 bytes from 127.0.53.53: icmp_seq=1 ttl=64 time=0.025 ms

root@c7c521c4a40c:/# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         172.17.42.1     0.0.0.0         UG    0      0        0 eth0
172.17.0.0      0.0.0.0         255.255.0.0     U     0      0        0 eth0

myapp.conf on nginx

server {
        listen          80;
        server_name     myapp.dev;
        root            /projects/MyApp/public;
        index           index.html index.htm index.php;

        fastcgi_connect_timeout 5000s;
        fastcgi_read_timeout 5000s;
        fastcgi_send_timeout 5000s;

        access_log /var/log/nginx-access.log;
        error_log /var/log/nginx-error.log;
        location / {
                try_files $uri $uri/ /index.php$is_args$args;
        }

        location ~ \.php$ {
                fastcgi_pass    web:9000;
                fastcgi_param   SCRIPT_FILENAME $document_root$fastcgi_script_name;
                include         fastcgi_params;
            fastcgi_param   APPLICATION_ENV dev;
        }
}

Does anybody have any clue?

get into both your containers with `docker exec -it` and debug with the usual netstat, ping, route, lsof -i:80 (you may need to install some of those), check also `docker logs` for your containers and have a look at `docker events` — user2915097, Mar 19 '15 at 11:36

score 0 · Answer 1 · answered Mar 19 '15 at 13:17

0

add the IP to your /etc/hosts file within your my-php container:

(ip of your nginx container) myapp.dev

Should get the result you need.

example:

111.111.111.111 foo.bar.com

answered Mar 19 '15 at 13:17

aholt

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13

Ok, that worked, but I have some problems with this solution, because I can't run my app automatically, i'll always have to update /etc/hosts with the nginx container's ip address. Even though it's possible to edit hosts on Docker using some tricks, I think maybe it's not the right solution – globo Mar 19 '15 at 14:59

Docker container can't reach another container using hostname

1 Answers1