CODEWITHSUNDEEP
macosdockerssh
Jeremy McJunkin
Jeremy McJunkin

Reputation: 428

Setup ssh tunnel from docker container on macos Mojave 10.14

I am having trouble setting up an ssh tunnel on my mac machine. I have no problems setting up the tunnel on my ubuntu box. This is the command I run

ssh -nNT -L 172.18.0.1:4000:production-database-url:3306 jump-point

When I run this on my mac, I get the following error:

bind [172.18.0.1]:4000: Can't assign requested address
channel_setup_fwd_listener_tcpip: cannot listen to port: 4000 Could
not request local forwarding.

If I run without the bind_address (172.18.0.1), I am able to connect to the database via the tunnel.

If I bind to all interfaces (0.0.0.0), then tunnel is open, however, the connection to the database from inside the docker container does not work.

Upvotes: 1

Views: 1204

Answers (1)

Davos
Davos

Reputation: 5415

172.18.0.1 is the IP of docker's default bridge network gateway, not your host's IP.
You can run this command to check that.

$ docker network inspect bridge

Docker for Mac has limitations

  • There is no docker0 bridge on macOS (it's in the docker VM host on Mac and on Windows)
  • You cannot ping containers (without shaving a bunch of yaks)
  • Per-container IP addressing is not possible

Also note that this means the docker run option --net-host is not supported on Mac, but maybe that's a good thing

There is a workaround

  • These magic addresses resolve to the host's IP from within a container
    • docker.for.mac.localhost (deprecated)
    • docker.for.mac.host.internal (deprecated)
    • host.docker.internal
  • This resolves to the gateway of the host mac
    • gateway.docker.internal

Use the name host.docker.internal from within the container just like you would use localhost on the mac directly.

Don't worry about the bind address for the tunnel:

ssh -nNT -L 4000:production-database-url:3306 jump-point

You didn't mention which database but I take it from the port 3306 that it is MySQL.

To connect using the mysql cli from within a container, via an ssh tunnel on your host, to a remote mysql database server you can run:

mysql --host host.docker.internal [... other options go here]

Upvotes: 5

Related Questions