CODEWITHSUNDEEP
dockerclouddigital-oceangrpc
Peteris
Peteris

Reputation: 3756

Docker container doesn't connect to another docker container on server

I'm using a Digital Ocean docker droplet and have 3 docker containers: 1 for front-end, 1 for back-end and 1 for other tools with different dependencies, let's call it back-end 2.

The front-end calls the back-end 1, the back-end 1 in turn calls the back-end 2. The back-end 2 container exposes a gRPC service over port 50051. Locally, by running the following command, I was able to identify the docker service to be running with the IP 127.17.0.1:

docker network inspect bridge --format='{{json .IPAM.Config}}'

Therefore, I understand that my gRPC server is accessible from the following url 127.17.0.1:50051 within the server.

Unfortunately, the gRPC server refuses connections when running from the docker droplet while it works perfectly well when running locally.

Any idea what may be different?

Upvotes: 1

Views: 815

Answers (3)

Santhosh Sundarasamy
Santhosh Sundarasamy

Reputation: 1

You could run docker binding to ip and port as shown by Aakash. Please restrict access to this specific IP and port to be accessed only from the other docker IP and port - this will help to run docker private and doesn't allow other (even the other docker/instances within your network).

Upvotes: 0

David Maze
David Maze

Reputation: 159865

You should generally set up a Docker private network to communicate between containers using their container names; see e.g. How to communicate between Docker containers via "hostname". The Docker-internal IP addresses are subject to change if you delete and recreate a container and aren't reachable from off-host, and trying to find them generally isn't a best practice.

172.17.0.0/16 is a typical default for the Docker-internal IP network (127.0.0.0/8 is the reserved IPv4 loopback network) and it looks like you might have typoed the address you got from docker network inspect.

Upvotes: 1

Akash Sharma
Akash Sharma

Reputation: 757

Try docker run with following command:

docker run -d -p {server ip}:12345 {back-end 2 image}

It will expose IP port to docker container and will be accessible from other servers.
Note: also check firewall rules, if firewall is blocking access.

Upvotes: 0

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