This question already has answers here:
From inside of a Docker container, how do I connect to the localhost of the machine?
(40 answers)
Closed 10 months ago.
I have a host that runs a native mysql installation (not a container).
From a docker container I now want to connect from a java spring-boot application to that port (3306 by default).
But it does not work:
docker-compose.yml:
version: '3.7'
services:
customer-app:
ports:
- "3306:3306"
environment:
SPRING_DATASOURCE_URL: jdbc:mysql://localhost:3306/db
Result from docker-compose up:
Cannot start service customer-app: driver failed programming external connectivity on endpoint:
Error starting userland proxy: listen tcp4 0.0.0.0:3306: bind: address already in use
This is probably not a question directly to a java application, but more general:
How can I access a port on the host system from inside a docker container?
I added the following to docker-compose.yml:
extra_hosts:
- "host.docker.internal:host-gateway"
environment:
SPRING_DATASOURCE_URL: jdbc:mysql://host.docker.internal:3306/db
Related
I have trouble understanding how docker port mapping works. I have a docker-compose file with a couple of containers, one of them is a rabbitmq service.
The docker-compose file is:
version: "3.9"
volumes:
test:
external: true
services:
rabbitmq3:
container_name: "rabbitmq"
image: rabbitmq:3.8-management-alpine
environment:
- RABBITMQ_DEFAULT_USER=myuser
- RABBITMQ_DEFAULT_PASS=mypassword
ports:
# AMQP protocol port
- '5671:5672'
# HTTP management UI
- '15671:15672'
So the container runs using docker compose up, no problem. But when I access the rabbitmq management plugin using container_ip:15671 or container_ip:15671, I don't get anything. But when I access it using 127.0.0.1:15672, I can access the management plugin.
It probably is a stupid question but how can I access the container service using localhost?
The port sematic is as such <HOST_PORT>:<CONTAINER_PORT>. So -p 15671:15672 implies that the container port 15672 is mapped to the port 15671 on your machine.
Based on your docker compose file, the ports 5671 and 15671 are exposed on your machine.
The management portal can be accessed using http://localhost:15671 and the rabbitmq service can be used using the http://localhost:5671.
The IP 127.0.0.1 is localhost.
This question already has answers here:
From inside of a Docker container, how do I connect to the localhost of the machine?
(40 answers)
Closed 1 year ago.
I have containerized a simple PHP app. It needs to connect to the host's database (localhost) and do some operations. However, while running the app, I have the following error:
Fatal error: Uncaught PDOException: SQLSTATE[HY000] [2002] No such file or directory ...
My docker-compose file looks like this:
version: "3.9"
services:
app:
build: .
stdin_open: true
tty: true
network_mode: "host"
restart: on-failure
Looks like dockerized app can't connect with localhost database. I added network_mode: "host", but it didn't help.
I use Docker Desktop and Mac OS.
Instead of localhost I had to use docker.for.mac.localhost in my PHP script.
This question already has answers here:
How to get Docker containers to talk to each other while running on my local host?
(4 answers)
Closed 2 years ago.
I want my Docker containers to work on the same IP. Is it possible? I want them to have the same IP address so that they can link to each other through it.
Have a look at https://docs.docker.com/compose/networking/ to learn how containers are made accessible with docker-compose.
The gist of it is that you access containers by the name you've given them in the compose-file. So in that example
version: "3.9"
services:
web:
build: .
ports:
- "8000:8000"
db:
image: postgres
ports:
- "8001:5432"
you can address the hosts as web and db.
I am attempting to connect to a rest end point of a JaxRS liferay portlet.
If I try and connect through postman using http://localhost:8078/engine-rest/process-definition
It works 200 okay.
I am attempting to connect to the same end point from within another docker container part of the same docker network, I have tried with localhost and I receive the error:
java.net.ConnectException: Connection refused (Connection refused)
I have also tried http://wasp-engine:8078, wasp-engine is the docker name of the container. Still receiving the same error.
Here are the two containers in my compose file:
wasp-engine:
image: in/digicor-engine:test
container_name: wasp-engine
ports:
- "8078:8080"
depends_on:
mysql:
condition: service_healthy
wasp:
image: in/wasp:local2
container_name: Wasp
volumes:
- liferay-document-library:/opt/liferay/data
environment:
- camundaEndPoint=http://wasp-engine:8078
ports:
- "8079:8080"
depends_on:
mysql:
condition: service_healthy
They are both connecting to the mysql fine which is part of the same docker network and referenced via:
jdbc.default.url=jdbc:mysql://mysql/liferay_test
tl;dr
Use http://wasp-engine:8080
The why
In your docker-compose the
ports: - "8078:8080"
field on wasp-engine will expose port 8080 of the docker container to your host computer on port 8078. This is what allows your postman to succeed in connecting to the container over localhost. However, once inside the docker container localhost refers to the docker container itself. This port forwarding no longer applies.
Using docker-compose you can use the name of the container to target the specific docker container. You mentioned you tried this with the URI http://wasp-engine:8078. When you access the container this way the original port is used not the forwarded port for the host machine. This means that the docker container should be targeting port 8080.
Putting it all together, the final URI should be http://wasp-engine:8080.
When all are run standalone outside of docker it works with no problem when core attempts to do a get from cerner. However, doing the same when all are dockerized as below I get:
Get http://cerner:8602/api/v1/patient/search: dial TCP 192.168.240.4:8602: connect: connection refused. The .4 is the IP of the cerner container and .2 is the IP of the core container
Cerner is the name of the container being called from core. If I change the name to the ip-address of the host server and use the ports, it works fine also. It just does not allow container to container using the containers DNS or IP. I have attempted with and without the private network and get the same thing.
The containers are all scratch go.
version: '3.7'
services: caConnector:
image: vertisoft/ca_connector:latest
ports:
- "8601:7001"
env_file:
- .env.ca_connector
networks:
- core-net
fhir:
image: vertisoft/fhir_connector:latest
container_name: cerner
ports:
- "8602:7002"
env_file:
- .env.fhir_connector
networks:
- core-net
core:
image: vertisoft/core:latest
ports:
- "8600:7000"
env_file:
- .env.core
networks:
- core-net
networks: core-net:
driver: bridge
You should call the container service with containerPort, not with hostPort in service to service communication. in your case, it should be 7000 to 7002 for any container to connect using container name.
Get http://cerner:8602/api/v1/patient/search: dial TCP
192.168.240.4:8602: connect: connection refused.
As in the error, it tries to attempt connection using publish port.
For example
version: "3"
services:
web:
build: .
ports:
- "8000:8000"
db:
image: postgres
ports:
- "8001:5432"
When you run docker-compose up, the following happens:
A network called myapp_default is created.
A container is created
using web’s configuration. It joins the network myapp_default under
the name web. A container is created using db’s configuration. It
joins the network myapp_default under the name db.
In v2.1+, overlay
networks are always attachable
Each container can now look up the hostname web or db and get back the
appropriate container’s IP address. For example, web’s application
code could connect to the URL postgres://db:5432 and start using the
Postgres database.
It is important to note the distinction between HOST_PORT and CONTAINER_PORT. In the above example, for db, the HOST_PORT is 8001 and the container port is 5432 (postgres default). Networked service-to-service communication use the CONTAINER_PORT. When HOST_PORT is defined, the service is accessible outside the swarm as well.
Within the web container, your connection string to db would look like postgres://db:5432, and from the host machine, the connection string would look like postgres://{DOCKER_IP}:8001.
compose-networking