This community is my last resort for this problem, as I have been fighting with this for several hours now.
I have a go app running in one container, in the other container I am running a postgres db. I am able to connect to the postgres db from my go application as long as only my postgres is within a container, and my go app is running locally as usual. However, when my go app is trying to access the postgres from within a docker container i am getting the following error:
dial tcp 127.0.0.1:8080: connect: connection refused
Below I try to provide enough information, but will gladly add more if requested.
I have 2 docker containers running with the following ports:
go application, port info: 8081/tcp -> 0.0.0.0:8081
postgres db, port info: 5432/tcp -> 0.0.0.0:8080
I am running the go app with:
docker run -it --rm --name gographqlserver --link postgresdb:postgres -d -p 8081:8081 gogogopher;
and the postgres db with:
docker run -it --rm --name postgresdb -e POSTGRES_PASSWORD=hello123 -d -p 8080:5432 postgresimage;
both containers can be started without any problems.
I have also tried connecting both containers within a docker network, which did not help.
help would be immensely appreciated!
You are using localhost address within the container which is not the same as your host's address. You should do one of the following instead:
Use your actual host's IP from app's container
Use postgresdb container's IP with the native port (5432). You can discover this IP using docker inspect postgresdb.
Use postgresdb as host name and the native port (5432) when connecting both containers to the same network
Related
I'm new to Docker. I successfully created a PostgreSQL container my-database and I am able to access it from SQLTools on my local machine with server address localhost and the port.
I got the containerized database's IP address from the following command:
docker container inspect my-database
But when I go back to SQLTools or the PHP web application (not containerized) and try to connect to my-database with the IP address I got above, it couldn't connect successfully.
What am I missing here?
FYI, I also created another container and was able to connect to my-database with the following way: Use the same network for both my-database and the second container.
It all depends on how you enable access to the database.
If your php service runs in the same machine, then localhost could work
If its on a different machine in the same network, then use the network IP assigned to that machine. If you have your php server in a totally different location, then you may want to use something like an nginx reverse proxy to your docker container.
So in your case you should get the ip:port where your db container runs and use that. Docker inspect shows the internal network ip which only helps other containers in the same virtual network connect to a container.
You never need the docker inspect IP address. You can only connect to it in two specific circumstances: if you're in a different container on the same Docker network, or if you're (a) not in a container at all, (b) on the same host, and (c) that host is running native Linux and not a different OS.
You've already identified the right answers. Say you start the container as
docker network create any-network-name
docker run \
--name database \
--net any-network-name \
-p 5432:5432 \
postgres
From another Docker container on the any-network-name network, you can use the database container name as a DNS name, and avoid the manual IP lookup; ignore any -p options and use the "normal" port for the service. From outside a container, you can use the host's DNS name or IP address (or, if it's the same host, localhost) and the first -p port number.
If you're running this in Docker Compose, it automatically creates a network for you and registers containers under their Compose service name; you do not need networks:, container_name:, or other similar settings.
version: '3.8'
services:
database:
image: postgres
ports: ['5432:5432']
application:
build: .
environment:
- PGHOST=postgres
I'm initializing my studies with docker. When I creating the postgreSQL container with Docker, appear this error:
I've already reinstall docker and tried change the database port, but must be don't have success
The error indicates that the 5432 port is already in use, in the HOST. This means that this port is occupied by another application. This could be for example a Postgres instance that you have on your machine or maybe another container using up this port.
The port option is -p hostPort:ContainerPort, so to have access to the Postgres port of the container which is 5432 in the host at port 5000 try:
-p 5000:5432
All the questions on SO about this seem to refer to an opposite case of creating a postgres container and connecting it from Mac host. But I am trying to do the opposite, without success. I have localhost running on my Mac host machine, and despite setting port flags, I cannot get code inside my container to talk to my localhost postgres (talks to remote host postgres just fine).
docker run -it -p 5000:5000 -p 5432:5432 yard-stats
Then inside docker:
telnet 0.0.0.0 5432
Trying 0.0.0.0...
telnet: Unable to connect to remote host: Connection refused
or telnet 127.0.0.1 or localhost. Connection is refused.
Edit: I also tried with flag --network="host", which did not change anything except break inbound connections to the container on localhost:5000 as well.
If you are using docker for mac, you can use use host.docker.internal special DNS name which resolves to the internal IP address used by the host.
You can also use --network="host" with your docker run command to run the container in host network. Then the localhost interface inside the container will be same as localhost interface of the host machine when run in host network. So you should be able to use localhost:5432 to connect to postgresql. You can remove -p option as it has no effect when running with --network="host".
docker run -it --network=host yard-stats
I have a simple setup of 2 docker containers, one for the database and one for the web service.
I start the DB docker container like so:
docker run -d --name dbs.service -p 5434:5432 -e POSTGRES_DB=my_app -e POSTGRES_USER=my_user -e POSTGRES_PASSWORD=my_password postgres:9.6.2
This works fine. And from localhost, i can connect to it fine as well (using pgcli for connection)
pgcli postgres://my_user:my_password#dbs.service:5434/my_app
Now I start the web service container, which works fine
docker run -d --name web.service --link dbs.service:dbs.service web-service:latest
However here's the problem. From inside the container, I cannot connect to DB using port 5434 but I can connect to DB using port 5432.
So I login to container using
docker exec -it web.service bash
Now this works
pgcli postgres://my_user:my_password#dbs.service:5432/my_app
but this does not
pgcli postgres://my_user:my_password#dbs.service:5434/my_app
I can't understand why it can connect to 5432 but not 5434. Any suggestions?
-p 5434:5432
This option publishes the port for access from outside of the docker host to your container. The host will listen on 5434 and route the traffic through to the container's port 5432.
However, container-to-container traffic doesn't use that. Container to container traffic simply needs a common docker network. From there, any container can talk to any other container on the same network. The port used is the container listening port, not the published port on the host. You don't even need to publish the port for it to be accessible by other containers.
Following this example: https://docs.docker.com/engine/examples/mongodb/
When trying to connect to mongoDB with: mongo ip:27017
(where ip is the name from boot2docker ip) + the port number from docker ps:
27017/tcp
or with -P
0.0.0.0:49155->27017/tcp
Either way I get the following errors:
warning: Failed to connect to ip:27017, reason: errno:61 Connection
refused
Error: couldn't connect to server ip:27017 (ip), connection attempt
failed at src/mongo/shell/mongo.js:148 exception: connect failed
If you specified the correct port and still not able to connect to mongodb running in docker (like me), make sure you are using the service name (or container name) in your connection URL, e.g. mongodb://mongodb_service:27017/mydb, which is defined in your docker-compose.yml :
services:
mongodb_service:
image: mongo
I was using the hostname value and that's not the correct thing to do. You could verify this by looking at docker inspect mongodb_service in the Aliases section.
I was using port 27017 instead of 49155 (doh, port forwarding)
0.0.0.0:49155->27017/tcp
Thanks to ZeissS
If you are on a Mac and using Docker Machine, do the following:
1. Get the name of the VM running docker daemon
$ docker-machine ls
2. Get the VM's IP info
$ docker-machine env
3. Connect with the mongo client to the VM IP and the mongo mapped port
$ mongo VM-IP:port
Assuming your mongodb is within a container, for other containers to connect to it, they all need to be on the same network.
To have mongodb and other containers (that want to connect it), create a new network using below command
docker network create --driver bridge my_bridge
Then run mongodb and other containers using the --net flag
docker run --net=my_bridge --name mongodb -p 27017:27017 mongodb
docker run --net=my_bridge --name my-service -p 7002:7002 my-service
Now you should be able to connect mongodb with given alias name from those containers
mongo --host "mongodb:27017"
DATABASE_URI=mongodb://mongo:27017/db_name
Should be the Database URI for a service definition like below (and not mongodb://localhost
or mongodb://IP). Use service name or container name.
services
mongo:
container_name: mongo
image: mongo
ports:
- '27017:27017'