Docker Access Localhost Service Mac Does Not

I can reach the running services from a browser with:port, but not the dynamo-local container.

Im trying to figure out if I have a dynamo issue, or a docker networking issue.

Docker Access Localhost Service Mac Does Not

Some platformssetups provide a bridge address that you can use to access the host system (frequently 172.17.0.116 on native Linux and 192.168.99.10024 on Docker ToolboxDocker Machine) but Docker for Mac does not have this.

The struggle Im having is that when I bring up a docker application such as a web server, it registers port 80:80 with the host and I can reach it by calling localhost:80 on my Mac.

Yes the services localhost is the docker container, but my host machine has 80 registered to it, left side right side of the 80:80 -p flag.

This works for most of my docker containers, but when I start dynamodb-local and register 8000:8000 I dont seem to be able to reach it as localhost:8000 as I do other containers with host mapped ports.

We just happen to use a custom one and I didnt bother trying with another image.

This is for development purpose and will not work in a production environment outside of Docker for Mac.

Although it IS possible to connect from a container to a host service with unused IP attach docs.docker.comdocker-for-macnetworking.

The MySql is running on localhost and not exposing a port to the outside world, so its bound on localhost, not bound on the ip address of the machine.

Even if you have the IP address of the docker host it does not mean you can connect to docker host from within the container given that IP address as your Docker network may be overlay, host, bridge, macvlan, none etc which restricts the reachability of that IP address.

A fix has been submitted on March the 8th, 2019 and will hopefully be merged to the code base.

Until then, a workaround is to use a container as described in qoomons answer.

Depending on the mode you choose you would connect to your MySQL database running on the docker host differently.

Both the docker host and the docker containers have an IP address on that bridge.

Such a container will share the network stack with the docker host and from the container point of view, localhost (or 127.0.0.1 ) will refer to the docker host.

That means your MySQL server could be reached from the Internet; make sure to setup firewall rules accordingly.

Oracle is a registered trademark of Oracle Corporation andor its affiliates.

I havent tried but I would assume you could create a separate network to connect containers over their own bridge offering them a common localhost.

You can bind whichever IP you want, just make sure youre not using it to anything else.

IN docker, one would expect that the hook docker.for.mac.localhost would be a generic docker internal name that would be valid for any operating system, not just for Mac.

With --nethost -e HOSTNAMElocalhost at least the container runs and complains that it cant find the service I need (MySQL db).

I did this script that works in both environments (even in Linux distribution with LANG en configured).

Thumbs up user833482 You should contribute more often to StackOverflow.

The mysql client library even uses unix sockets by default when connecting to localhost rather than actually making a connection to localhost.

A unix socket avoids the overhead of the TCP stack and routing, and should run faster.

So in you connection string, use your computer name as a server name.

I needed to do something similar, that is connect from my Docker container to my localhost, which was running the Azure Storage Emulator and CosmosDB Emulator.

When accessing your DB, remember to use the name you specified before, in this case dockerhost and the port of your host in which the DB is running.

Microsoft is completely silent on this when it talks about connecting to MSSQL from within a Docker container.

Docker For Mac Access Localhost Service