My scenario is the following: I have a postgres 12 installed on ubuntu 20.04 server and a docker container running in another host with ipv6 enabled.
I can't reach postgres server from inside docker container using ipv6.
these commands works from within the container:
$ ping POSTGRES_SERVER_IPv4
$ ping POSTGRES_SERVER_IPv6
$ telnet POSTGRES_SERVER_IPv4 5432
but this does not work from inside the container (but it works from the docker host):
$ telnet POSTGRES_SERVER_IPv6 5432
i've already set listen_address = '*' and "host all all md5" in postgres pg_hba.conf.
EDIT:
i've realized that my network adapter is using two IPv6, the static one that I defined in netplan and another one that is within my network range, but I didn't assigned it.
In your netplan configuration, try to add:
accept-ra: no
example:
network:
version: 2
ethernets:
ens192:
accept-ra: no
addresses: ...
Related
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'm trying to run a docker image of rundeck, using PostGres for the database.
The issue I'm having is mapping my local postgres installation to the docker rundeck image. The postgres port runs on 5432, and have confirmed using netstat that the port is open and listening. The port for rundeck needs to run on 4440.
I have tried the following command:
docker run -p 127.0.0.1:4440:4440 -e RUNDECK_DATABASE_URL=jdbc:postgresql://localhost/rundeck -e RUNDECK_DATABASE_DRIVER=org.postgresql.Driver -e RUNDECK_DATABASE_USERNAME=xxx -e RUNDECK_DATABASE_PASSWORD=xxx --name test-rundeck -t rundeck/rundeck:3.0.19
But it fails with an error: Connection to 127.0.0.1:5432 refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP
I'm guessing it's because the internal 5432 port isnt mapped to the docker container port 5432?
I tried mapping the ports with -p 127.0.0.1:5432:5432 but that fails with the error:
Error starting userland proxy: listen tcp 127.0.0.1:5432: bind: address already in use
At this point I might just resort to running both PostGres and Rundeck as docker images, but I would rather like to resolve this problem.
Any ideas on how to map a local PostGres to a docker ran Rundeck?
Found the answer.
Had to edit the pg_hba.conf file to allow the docker0 ip address through.
host all all 172.23.0.0/16 md5
I am running Postgres on a Windows 10 computer, and I want to connect to it from a Docker container. I've followed instructions from many sources and things should be working, but they're not.
Command line used to create Docker container:
docker run --rm -d --network=host --name mycontainer myimage
In postgresql.conf:
listen_addresses = '*'
In pg_hba.conf:
host all all 172.17.0.0/16 trust
In the bash shell of my container, I run:
psql -h 127.0.0.1
and I get the error:
psql: could not connect to server: Connection refused
Is the server running on host "127.0.0.1" and accepting TCP/IP connections on port 5432?
Needless to say, Postgres is definitely running on my computer and I am able to query it from local applications. What am I missing?
THIS WON'T WORK FOR DOCKER v18.03 AND ONWARDS
The answer is already there - From inside of a Docker container, how do I connect to the localhost of the machine?
This question is related to a mysql setup, but it should work for your case too.
FOR DOCKER v18.03 ONWARDS
Use host.docker.internal to refer to the host machine.
https://docs.docker.com/docker-for-windows/networking/#i-cannot-ping-my-containers
As you've discovered, --network-host doesn't work with Docker for Windows or Docker for Mac. It only works on Linux hosts.
One option for this scenario might be to host PostgreSql in a container, also. If you deploy them with a docker-compose file, you should be able to have two separate Docker containers (one for the database and one for your service) that are networked together. By default, docker-compose will expose containers to others in the same compose file using the container name as its DNS name.
You could also consider including the database in the same container as your service, but I think the docker-compose solution is better for several reasons:
It adheres to the best practice of each container having only a single process and single responsibility.
It means that you can easily change and re-deploy your service without having to recreate the database container.
Configure the connection inside your docker container with the real ip-address of your host or as workaround with a dns name
I got postgres.app running locally on my Mac and would like my local docker container to be able to connect to it. How do I best do this?
I found this post that suggests to pass the Docker host’s IP address to a container using the --add-host flag (Host port with DB to Docker container). However, my laptop's IP address changes frequently. Isn't there an easier way of doing this? Isn't there an easy way to open a local port to a container?
Few things
Use docker.for.mac.localhost as your HOST (This assumes you have the latest Docker for Mac as #Pete mentioned)
Make sure there is such a record in ~/Library/Application Support/Postgres/var-9.6/pg_hba.conf
host all all 0.0.0.0/0 trust
Change this line listen_addresses = 'localhost' in ~/Library/Application Support/Postgres/var-9.6/postgresql.conf
to
listen_addresses = '*'
or
listen_addresses = 'localhost, docker.for.mac.localhost'
If we are talking about a developers workstations, you could start your Docker Container inside the Host Network.
docker run --net=host myContainer
So your container runs in the same stack as your Host, and should be able to access your postgres.app.
From your container, try connecting to hostname docker.for.mac.localhost. For example:
psql -U my_user docker.for.mac.localhost -U my_user my_database
From the docs:
The Mac has a changing IP address (or none if you have no network
access). From 17.06 onwards our recommendation is to connect to the
special Mac-only DNS name docker.for.mac.localhost which will resolve
to the internal IP address used by the host.
Note: this requires Docker for Mac >= 17.06.0-ce-mac18, 2017-06-28
I've got a docker container which is supposed to run a (HTTP) service.
This container should be able to connect to PostgresSQL running on the host machine (so it's not part of the container). The container uses the host's network settings:
docker run -e "DBHOST=localhost:5432" -e "DB=somedb" -e "AUTH=user:pw" -i -t --net="host" myservice
I'm using MacOSX, so Docker is running on a Virtualbox VM. I guess I need port forwarding to make this work. I've tried to configure that:
VBoxManage controlvm "default" natpf1 "rule1,tcp,,5432,,5432";
But this doesn't work. If I start up the service, all I get is a connection refused message and the service cannot connect to Postgres.
Postgres is running on port 5432, on the host machine. The "default" is the name of the VM created by Docker installer.
What am I doing wrong? Please help!
I've had success with this using the --add-host flag, which adds an entry into the /etc/hosts in your container. Boot2docker and docker-machine both assign an ip you can use to hit your localhost from inside a container, so you just want to add an entry that points back to this.
With boot2docker, where the default host ip is 192.168.59.3, you can just do docker run --add-host=my_localhost:192.168.59.3 ...
With docker-machine, I think you'll need to lookup your localhost's mapped ip in Virtualbox, and then you can do the same: docker run --add-host=my_localhost:[localhost_mapped_ip_from_docker] ...
Try setting that up and then trying to connect to your Postgres instance through my_localhost. Make sure you correctly set access and accepted inbound ip permissions in Postgres as well, as if it's not listening on the container's ip or 0.0.0.0, it won't work no matter what.