I have two containers with different default networks and I want to communicate with each other. First I made a common network named "my_network" then enter into the container1's bash. I could ping the other container by name (container2) but when I tried to check the telnet with port 4000, I got the error:
telnet: Unable to connect to remote host: Connection refused
Curl request also didn't work. But, when I replaced the container name with the host's ip address (eg. 10.244.140.92), everything just worked fine. So what am I doing wrong?
My simplified compose:
version: "3.9"
networks:
my_network:
driver: bridge
external: true
default:
services:
container1:
image: ...
ports:
- 5000:80
- 5001:443
networks:
- default
- my_network
version: "3.9"
networks:
my_network:
services:
container2:
image: ...
ports:
- 4000:4000
networks:
- my_network
Related
I need to resolve a container name to the IP Address from the docker host.
The reason for this is, i need a container to run on the host network, but it must be also able to resolve the container "backend" which it connects also to. (The container must be send & receive multicast packets)
docker-compose.yml
version: "3"
services:
database:
image: mongo
container_name: database
hostname: database
ports:
- "27017:27017"
backend:
image: "project/backend:latest"
container_name: backend
hostname: backend
environment:
- NODE_ENV=production
- DATABASE_HOST=database
- UUID=5025f846-7587-11ed-9ca7-8b992b5e7dd3
ports:
- "8080:8080"
depends_on:
- database
tty: true
frontend:
image: "project/frontend:latest"
container_name: frontend
hostname: frontend
ports:
- "80:80"
- "443:443"
depends_on:
- backend
environment:
- BACKEND_HOST=backend
connector:
image: "project/connector:latest"
container_name: connector
hostname: connector
ports:
- "1900:1900/udp"
#expose:
# - "1900/udp"
environment:
- NODE_ENV=production
- BACKEND_HOST=backend
- STARTUP_DELAY=1500
depends_on:
- backend
network_mode: host
tty: true
How can i resolve the hostname "backend" via docker from the docker host?
dig backend #127.0.0.11 & dig backend #172.17.0.1 did not work.
A test with a docker ubuntu image & socat proves, that i can receive ssdp multicast packets:
docker run --net host -it --rm ubuntu
socat UDP4-RECVFROM:1900,ip-add-membership=239.255.255.250:0.0.0.0,fork -
The only problem i now have is the DNS/Container name resolution from the host (network).
TL;DR
The container "connector" must be on the host network,but also be able to resolve the container name "backend" to the docker internal IP Address.
NOTE: Perhaps this is better suited on superuser or similar?
I'm trying to run two Docker containers attached to a single Docker network using Docker Compose.
I'm running into the following error when I run the containers:
Error response from daemon: failed to add interface veth5b3bcc5 to sandbox:
error setting interface "veth5b3bcc5" IP to 172.19.0.2/16:
cannot program address 172.19.0.2/16 in sandbox
interface because it conflicts with existing
route {Ifindex: 10 Dst: 172.19.0.0/16 Src: 172.19.0.1 Gw: <nil> Flags: [] Table: 254}
My docker-compose.yml looks like this:
version: '3'
volumes:
dsn-redis-data:
driver: local
dsn-redis-conf:
driver: local
networks:
dsn-net:
driver: bridge
services:
duty-students-notifier:
image: duty-students-notifier:latest
network_mode: host
container_name: duty-students-notifier
build:
context: ../
dockerfile: ./docker/Dockerfile
env_file: ../.env
volumes:
- /etc/timezone:/etc/timezone:ro
- /etc/localtime:/etc/localtime:ro
networks:
- dsn-net
restart: always
dsn-redis:
image: redis:latest
expose:
- 5432
volumes:
- dsn-redis-data:/var/lib/redis
- dsn-redis-conf:/usr/local/etc/redis/redis.conf
networks:
- dsn-net
restart: always
Thanks!
The network_mode: host setting generally disables Docker networking, and can interfere with other options. In your case it looks like it might be trying to apply the networks: configuration to the host system network layer.
network_mode: host is almost never necessary, and deleting it may resolve this issue.
I have a problem about network in docker. In the docker-compose.yml includes 2 instance below
webserver (frontend + backend)
database
But i tried to bridge network and default but not working at all.The backend cannot connect to database show error "connection refuse". then i tried to docker exec -t .. into webserver and then ping to database it show "timeout".
I cannot connect database with ip address (i got a database ip address from docker exec and then hostname -i) but i connected success using "localhost"
this my docker-compose.yml
version: '3.8'
services:
postgres_server:
container_name: postgres14-4_container
image: postgres:14.4
command: postgres -c 'max_connections=200'
restart: always
environment:
- POSTGRES_USER=postgres
- POSTGRES_PASSWORD=postgres
ports:
- '5222:5432'
volumes:
- db:/var/lib/postgresql14/data
networks:
- web_network
webserver:
container_name: frontend_backend_container
image: webserver
ports:
- '9090:80'
- '8081:8081'
env_file:
- backend_env
depends_on:
- postgres_server
restart: always
networks:
- web_network
volumes:
db:
driver: local
networks:
web_network:
driver: bridge
To configure remote connections to postgres, you have to adjust pg_hba.conf. For example add:
# Remote access
host all all 0.0.0.0/0 trust
where is your backend_env file?
I guess you have there the host + port to connect to the db.
You don't need to define anything special (like the bridge).
The webserver container should be able to access the postgres_server via postgres_server:5432 (not localhost and not 5222).
I have a backuppc local service running e.g. 127.0.0.1:8081 .
I can also reach it directly on http://172.23.0.4 (container ip)
docker-compose.yml
version: '3.7'
services:
backuppc-app:
image: tiredofit/backuppc
container_name: backuppc-app
ports:
- "8081:80"
- "8082:10050"
environment:
- BACKUPPC_UUID=1000
- BACKUPPC_GUID=1000
restart: always
depends_on:
- backuppc-mysql
networks:
- nginx-proxy
I want to assign it a hostname, something like
hostname: backup.local
I tried to add it but doesn't work as expected
backuppc-app:
image: tiredofit/backuppc
container_name: backuppc-app
hostname: backup.local
Should I manually edit my local /ets/hosts ?
172.23.0.4 backup.local
You can add a hostname as a network alias:
version: '3.7'
services:
backuppc-app:
networks:
nginx-proxy:
aliases:
- backup.local
For containers in nginx-proxy network it will be available both as backuppc-app and as backup.local.
If you want that hostname to be visible to your host you need to modify hosts file. But don't put container IP there - it can change. Rather add it as another name for localhost:
127.0.0.1 localhost myhostname backup.local
Then you can access it both with localhost:8081 and backup.local:8081 (that works due to port forwarding you've declared with ports: key).
Current compose yaml:
version: '3.7'
networks:
app-tier:
driver: bridge
services:
php:
container_name: docker_php
build: .docker/php73
volumes:
- .:/srv/
networks:
- app-tier
rabbitmq:
container_name: docker_rabbitmq
image: "rabbitmq:3-management"
hostname: "rabbitmq-localhost"
environment:
RABBITMQ_DEFAULT_USER: guest
RABBITMQ_DEFAULT_PASS: guest
ports:
- "15672:15672"
- "5672:5672"
networks:
- app-tier
My target is to reach docker_rabbitmq container from docker_php within localhost:
#bash php_container
telnet loaclhost 15672
How can I configure a network that:
container A has port mapping on localhost to Container B?
you're limited by the inner port, which means if your two containers are in the same docker defined network, you can use the internally opened ports of the respective container. For the hostname to be defined for a container in a different one, you can use the links attribute in the service definition inside your docker-compose.yml.
Consider a micro service which you want to be only accessed by only the containers on that network therefore exposing the ports on the host wouldn't make sense. Now assuming rabbitmq is the service that you want to access from php service, you need to define a link to rabbitmq in your php service definition( please not the link/host-definition is not bi-directional, if you need php in your rabbitmq you need to define a link in rabbitmq for php)
version: '3.7'
networks:
app-tier:
driver: bridge
services:
php:
container_name: docker_php
build: .docker/php73
volumes:
- .:/srv/
networks:
- app-tier
links:
- rabbitmq
rabbitmq:
container_name: docker_rabbitmq
image: "rabbitmq:3-management"
hostname: "rabbitmq-localhost"
environment:
RABBITMQ_DEFAULT_USER: guest
RABBITMQ_DEFAULT_PASS: guest
networks:
- app-tier
Now you can access the internal ports of the rabbitmq from php but note the expternal ports are not accessible, those are for the host.
# inside your `php` container `bash`
telnet rabbitmq <internal_port>
Also not that I got rid of the ports in rabbitmq by removing
now these ports of rabbitmq are not accessible from the host.
Update
if you want to access the ports, such that the ports opened in rabbitmq are accessible in php on localhost. the easiest and the simplest way would be to configure rabbitmq to run in container network mode on the network of php to do this simple add
network_mode: "container:[container name/id]"
rabbitmq:
container_name: docker_rabbitmq
image: "rabbitmq:3-management"
hostname: "rabbitmq-localhost"
environment:
RABBITMQ_DEFAULT_USER: guest
RABBITMQ_DEFAULT_PASS: guest
network_mode: "container:php"
ports:
- "15672:15672"
- "5672:5672"